Hi Pilato,
This is my original data. How to push this one to elasticsearch.
{"id":"RE037490","d":"20020101","t":"Old
Xml","pd":{"PATDOC":{"SDOCL":{"H":{"LVL":"1","STEXT":{"PDAT":"What is
claimed
is:"}},"CL":{"CLM":[{"ID":"CLM-00001","CLMSTEP":[{"LVL":"2","PTEXT":{"PDAT":"a
slide;"}},{"LVL":"2","PTEXT":{"PDAT":"an elongated beam having a measuring
axis, the slide movable along the measuring
axis;"}},{"LVL":"2","PTEXT":{"PDAT":"at least one magnetic field generator,
each magnetic field generator responsive to a drive signal to generate a
first changing magnetic flux in a first flux
region;"}},{"LVL":"2","PTEXT":{"PDAT":"at least one flux coupling loop, a
first portion of the at least one flux coupling loop positionable within
the first flux region and responsive to the first changing magnetic flux
when positioned within the first flux region to produce a second changing
magnetic flux in a second portion of the flux coupling loop in a second
flux region that is separated from the first flux region;
and"}},{"LVL":"2","PTEXT":{"PDAT":"at least one magnetic flux
sensor;"}},{"LVL":"2","PTEXT":{"PDAT":"wherein:"}},{"LVL":"3","PTEXT":{"PDAT":"one
of a) the at least one magnetic flux sensor or b) the at least one magnetic
field generator includes an inductive area extending along the measuring
axis, and the inductive area is spatially modulated along the measuring
axis in a pattern including alternating increases and decreases in
width,"}},{"LVL":"3","PTEXT":{"PDAT":"each magnetic flux sensor is
positioned outside the first flux region to sense the second changing
magnetic flux in the second flux region portion of at least one flux
coupling loop, and"}},{"LVL":"3","PTEXT":{"PDAT":"each magnetic flux sensor
is responsive to the second changing magnetic flux to generate an output
signal which is a function of the relative position between the slide and
the elongated
beam."}}],"PARA":{"LVL":"0","ID":"P-00157","PTEXT":{"PDAT":"1. An
electronic caliper
comprising:"}}},{"ID":"CLM-00002","PARA":{"LVL":"0","ID":"P-00158","PTEXT":{"PDAT":["2.
The electronic caliper of",", wherein the inductive area comprises a
plurality of alternating polarity
regions."],"CLREF":{"ID":"CLM-00001","PDAT":"claim
1"}}}},{"ID":"CLM-00003","PARA":{"LVL":"0","ID":"P-00159","PTEXT":{"PDAT":["3.
The electronic caliper of",", wherein the pattern of alternating polarity
regions comprises regions along a surface, the regions bounded by at least
one conductor positioned on the surface in a prescribed
pattern."],"CLREF":{"ID":"CLM-00002","PDAT":"claim
2"}}}},{"ID":"CLM-00004","PARA":{"LVL":"0","ID":"P-00160","PTEXT":{"PDAT":["4.
The electronic caliper of",", wherein the one of a) the at least one
magnetic field generator or b) the at least one magnetic flux sensor which
has the inductive area spatially modulated along the measuring axis is
positioned on one of the slide and the elongated beam, and the at least one
flux coupling loop is positioned on the other one of the slide and the
elongated beam."],"CLREF":{"ID":"CLM-00001","PDAT":"claim
1"}}}},{"ID":"CLM-00005","PARA":{"LVL":"0","ID":"P-00161","PTEXT":{"PDAT":["5.
The electronic caliper of",", wherein the other of a) the at least one
magnetic field generator and b) the at least one magnetic flux sensor is
positioned on either the slide or the elongated
beam."],"CLREF":{"ID":"CLM-00004","PDAT":"claim
4"}}}},{"ID":"CLM-00006","PARA":{"LVL":"0","ID":"P-00162","PTEXT":{"PDAT":["6.
The electronic caliper of",", wherein in the absence of the at least one
flux coupling loop, the output signal generated by each magnetic flux
sensor is insensitive to the changing magnetic flux generated by each
magnetic field generator."],"CLREF":{"ID":"CLM-00001","PDAT":"claim
1"}}}},{"ID":"CLM-00007","PARA":{"LVL":"0","ID":"P-00163","PTEXT":{"PDAT":["7.
The electronic caliper of",", wherein the at least one magnetic field
generator, the at least one flux coupling loops and the at least one
magnetic flux sensor are fabricated by printed circuit board
processing."],"CLREF":{"ID":"CLM-00001","PDAT":"claim
1"}}}},{"ID":"CLM-00008","CLMSTEP":[{"LVL":"2","PTEXT":{"PDAT":"an energy
supply source that outputs a power supply;"}},{"LVL":"2","PTEXT":{"PDAT":"a
drive circuit that inputs the power supply and outputting a drive signal to
the at least one magnetic field generator during each measurement cycle;
and"}},{"LVL":"2","PTEXT":{"PDAT":"an analyzing circuit that inputs the
output signal from each at least one magnetic field sensor, determines the
position of the slide relative to the elongated beam, and outputs a
position signal indicative of the position of the slide relative to the
elongated beam at a first level of
resolution."}}],"PARA":{"LVL":"0","ID":"P-00164","PTEXT":{"PDAT":["8. The
electronic caliper of",", further
comprising:"],"CLREF":{"ID":"CLM-00001","PDAT":"claim
1"}}}},{"ID":"CLM-00009","PARA":{"LVL":"0","ID":"P-00165","PTEXT":{"PDAT":["9.
The electronic caliper of",", wherein the drive circuit comprises a
capacitor discharged through the at least one magnetic field
generator."],"CLREF":{"ID":"CLM-00008","PDAT":"claim
8"}}}},{"ID":"CLM-00010","PARA":{"LVL":"0","ID":"P-00166","PTEXT":{"PDAT":["10.
The electronic caliper of",", wherein the capacitor and the at least one
magnetic field generator form a resonant
circuit."],"CLREF":{"ID":"CLM-00009","PDAT":"claim
9"}}}},{"ID":"CLM-00011","PARA":{"LVL":"0","ID":"P-00167","PTEXT":{"PDAT":["11.
The electronic caliper of",", wherein the analyzing circuit comprises a
counter for counting fractions of cycles of the at least one output signal
output from the at least one magnetic field sensor at a second level of
resolution coarser than the first level of resolution in response to motion
of the slide along the measuring
axis."],"CLREF":{"ID":"CLM-00008","PDAT":"claim
8"}}}},{"ID":"CLM-00012","CLMSTEP":{"LVL":"2","PTEXT":{"PDAT":"the
analyzing circuit substantially eliminates the influence of signal
components which are third harmonics of the wavelength
W."}},"PARA":{"LVL":"0","ID":"P-00168","PTEXT":{"PDAT":["12. The electronic
caliper of",", wherein each of a plurality of 3N, where N is greater than
or equal to 1, of magnetic flux sensors comprise identical inductive areas
spatially modulated along the measuring axis with a periodic modulation
having a wavelength W, and such inductive areas are offset from each other
by a length O###equals;W/3N along the measuring axis;
and"],"CLREF":{"ID":"CLM-00008","PDAT":"claim
8"}}}},{"ID":"CLM-00013","PARA":{"LVL":"0","ID":"P-00169","PTEXT":{"PDAT":["13.
The electronic caliper of",", wherein the changing magnetic flux generated
by the at least one magnetic field generator changes at a rate equivalent
to an oscillation frequency of at least 1
MHz."],"CLREF":{"ID":"CLM-00001","PDAT":"claim
1"}}}},{"ID":"CLM-00014","PARA":{"LVL":"0","ID":"P-00170","PTEXT":{"PDAT":["14.
The electronic caliper of",", wherein the pattern including alternating
increases and decreases in width comprises a periodic pattern having a
selected wavelength."],"CLREF":{"ID":"CLM-00001","PDAT":"claim
1"}}}},{"ID":"CLM-00015","PARA":{"LVL":"0","ID":"P-00171","PTEXT":{"PDAT":["15.
The electronic caliper of",", wherein the portion of each coupling loop
adjacent the periodic pattern spans, at most, one-half wavelength along the
measuring axis."],"CLREF":{"ID":"CLM-00014","PDAT":"claim
14"}}}},{"ID":"CLM-00016","PARA":{"LVL":"0","ID":"P-00172","PTEXT":{"PDAT":["16.
The electronic caliper of",", wherein a first plurality of coupling loops
of a first type are arranged along the measuring axis at a pitch equal to
the wavelength."],"CLREF":{"ID":"CLM-00014","PDAT":"claim
14"}}}},{"ID":"CLM-00017","PARA":{"LVL":"0","ID":"P-00173","PTEXT":{"PDAT":["17.
The electronic caliper of",", wherein a second plurality of coupling loops
of a second type are arranged along the measuring axis offset by one-half
wavelength from the first plurality of coupling loops and at a pitch equal
to the wavelength, and the coupling loops of the first and second type
alternate along the measuring axis in at least the region adjacent to the
periodic pattern."],"CLREF":{"ID":"CLM-00016","PDAT":"claim
16"}}}},{"ID":"CLM-00018","PARA":{"LVL":"0","ID":"P-00174","PTEXT":{"PDAT":["18.
The electronic caliper of",", wherein, in one of the first or second
coupling loop types, the induced current produces the same polarity flux in
the first flux region portion and the second flux region portion, and, in
the other of the first or second coupling loop types, the induced current
produces flux in the second flux region portion which is opposite in
polarity to the flux induced in the first flux region
portion."],"CLREF":{"ID":"CLM-00017","PDAT":"claim
17"}}}},{"ID":"CLM-00019","PARA":{"LVL":"0","ID":"P-00175","PTEXT":{"PDAT":["19.
The electronic caliper of",", wherein the first and second coupling loop
types couple to the same magnetic flux generator region and are configured
so that coupling loops of the first type extend in a first direction
perpendicular to the measuring axis to couple to a first magnetic flux
sensor region and the coupling loops of the second type extend in an
opposite direction perpendicular to the measuring axis to couple to a
second magnetic flux sensor
region."],"CLREF":{"ID":"CLM-00017","PDAT":"claim
17"}}}},{"ID":"CLM-00020","PARA":{"LVL":"0","ID":"P-00176","PTEXT":{"PDAT":["20.
The electronic caliper of",", wherein the first and second coupling loop
types couple to the same magnetic flux sensor region, but are configured so
that coupling loops of the first type extend in a first direction
perpendicular to the measuring axis to couple to a first magnetic flux
generator region and the coupling loops of the second type extend in an
opposite direction perpendicular to the measuring axis to couple to a
second magnetic flux generator
region."],"CLREF":{"ID":"CLM-00017","PDAT":"claim
17"}}}},{"ID":"CLM-00021","PARA":{"LVL":"0","ID":"P-00177","PTEXT":{"PDAT":["21.
The electronic caliper of",", wherein a) the at least one magnetic flux
generator or b) the at least one magnetic flux sensor comprises two similar
portions arranged symmetrically on opposite sides of the other of the at
least one magnetic flux generator and the at least one magnetic flux
sensor, such that in absence of coupling loops, the net flux through the
magnetic flux sensor is substantially zero as a result of the symmetric
configuration."],"CLREF":{"ID":"CLM-00001","PDAT":"claim
1"}}}},{"ID":"CLM-00022","PARA":{"LVL":"0","ID":"P-00178","PTEXT":{"PDAT":["22.
The electronic caliper of",", wherein the at least one flux coupling loop
comprises a plurality of flux coupling loops arranged along the measuring
axis and the measuring range of the sensor is determined by the extent of
the plurality of coupling loops."],"CLREF":{"ID":"CLM-00001","PDAT":"claim
1"}}}},{"ID":"CLM-00023","PARA":{"LVL":"0","ID":"P-00179","PTEXT":{"PDAT":["23.
The electronic caliper of",", wherein each of a plurality of the inductive
areas which are spatially modulated along the measuring axis comprises an
area outlined by a patterned conductor insulated from other patterned
conductors, and a plurality of such inductive areas at least partially
overlap."],"CLREF":{"ID":"CLM-00001","PDAT":"claim
1"}}}},{"ID":"CLM-00024","PARA":{"LVL":"0","ID":"P-00180","PTEXT":{"PDAT":["24.
The electronic caliper of",", wherein each of a plurality of N inductive
areas which are spatially modulated along the measuring axis is identical
and is periodically modulated along the measuring axis with a selected
wavelength W, and such inductive areas are offset from each other by a
length O along the measuring axis, where O###equals;W/2N for N equal to 2,
and O###equals;W/N for N greater than
2."],"CLREF":{"ID":"CLM-00023","PDAT":"claim
23"}}}},{"ID":"CLM-00025","CLMSTEP":[{"LVL":"2","PTEXT":{"PDAT":"a
slide;"}},{"LVL":"2","PTEXT":{"PDAT":"an elongated beam having a measuring
axis, the slide movable along the measuring
axis;"}},{"LVL":"2","PTEXT":{"PDAT":"a low power energy supply source on
the slide capable of providing a power supply to a drive circuit on the
slide;"}},{"LVL":"2","PTEXT":{"PDAT":"the drive circuit connected to the
power supply and responsive to a control signal to output an intermittent
drive signal;"}},{"LVL":"2","PTEXT":{"PDAT":"at least one magnetic field
generator on the slide, each magnetic field generator responsive to the
drive signal to generate a first changing magnetic flux in a first flux
region;"}},{"LVL":"2","PTEXT":{"PDAT":"at least one flux coupling loop on
the elongated beam, a first portion of the at least one flux coupling loop
positionable within the first flux region and responsive to the first
changing magnetic flux when positioned within the first flux region to
produce a second changing magnetic flux in a second flux region proximate
to a second portion of the flux coupling loop outside the first flux
region;"}},{"LVL":"2","PTEXT":{"PDAT":"at least one magnetic flux sensor on
the slide, each magnetic flux sensor positioned outside the first flux
region for sensing the second changing magnetic flux in the second flux
region portion of the at least one flux coupling loop, and each magnetic
flux sensor responsive to the second changing magnetic flux to generate an
output signal which is a function of the relative position between the
magnetic flux sensor and the at least one flux coupling loop;
and"}},{"LVL":"2","PTEXT":{"PDAT":"an analyzing circuit on the slide
responsive to the output signal from at least one magnetic flux sensor to
output an output signal indicative of the position of the slide relative to
the elongated beam at a first level of
resolution."}}],"PARA":{"LVL":"0","ID":"P-00181","PTEXT":{"PDAT":"25. An
electronic caliper
comprising:"}}},{"ID":"CLM-00026","PARA":{"LVL":"0","ID":"P-00182","PTEXT":{"PDAT":["26.
The electronic caliper of",", wherein the drive circuit comprises a
capacitor that discharges through the magnetic field
generator."],"CLREF":{"ID":"CLM-00025","PDAT":"claim
25"}}}},{"ID":"CLM-00027","PARA":{"LVL":"0","ID":"P-00183","PTEXT":{"PDAT":["27.
The electronic caliper of",", wherein the capacitor and the magnetic field
generator operate as a resonant
circuit."],"CLREF":{"ID":"CLM-00026","PDAT":"claim
26"}}}},{"ID":"CLM-00028","PARA":{"LVL":"0","ID":"P-00184","PTEXT":{"PDAT":["28.
The electronic caliper of",", wherein the first changing magnetic flux
changes at a rate equivalent to an oscillation frequency of at least 1 MHz
in response to the intermittent drive
signal."],"CLREF":{"ID":"CLM-00026","PDAT":"claim
26"}}}},{"ID":"CLM-00029","PARA":{"LVL":"0","ID":"P-00185","PTEXT":{"PDAT":["29.
The electronic caliper of",", wherein the intermittent drive signal
comprises at least one pulse
signal."],"CLREF":{"ID":"CLM-00026","PDAT":"claim
26"}}}},{"ID":"CLM-00030","PARA":{"LVL":"0","ID":"P-00186","PTEXT":{"PDAT":["30.
The electronic caliper of",", wherein the analyzing circuit determines
changes in the relative position at a coarse level of resolution during
each pulse interval, and determines the relative position at a finer level
of resolution once during a plurality of pulse
intervals."],"CLREF":{"ID":"CLM-00029","PDAT":"claim
29"}}}},{"ID":"CLM-00031","PARA":{"LVL":"0","ID":"P-00187","PTEXT":{"PDAT":["31.
The electronic caliper of",", wherein the analyzing circuit includes
synchronous sampling means for sampling the output signal from at least one
magnetic flux sensor synchronously with the pulse
signal."],"CLREF":{"ID":"CLM-00029","PDAT":"claim
29"}}}},{"ID":"CLM-00032","PARA":{"LVL":"0","ID":"P-00188","PTEXT":{"PDAT":["32.
The electronic caliper of",", wherein the synchronous sampling uses sample
timing based on an expected time delay between the pulsed signal and a peak
in a response to a resonant circuit formed by the pulse generator
components and the magnetic field generator
components."],"CLREF":{"ID":"CLM-00031","PDAT":"claim
31"}}}},{"ID":"CLM-00033","CLMSTEP":[{"LVL":"2","PTEXT":{"PDAT":"at least
one of a) the at least one magnetic flux sensor, and b) the at least one
magnetic field generator includes an inductive area extending along the
measuring axis, and the inductive area is spatially modulated along the
measuring axis in a pattern including alternating increases and decreases
in width;"}},{"LVL":"2","PTEXT":{"PDAT":"the output signal from each
magnetic flux sensor exhibits spatial cycles which are a function of a
relative position between the magnetic flux sensor and the at least one
flux coupling loop; and"}},{"LVL":"2","PTEXT":{"PDAT":"the analyzing
circuit comprises a counter for counting fractions of cycles of the output
signal from the at least one magnetic flux sensor in response to motion of
the slide along the elongated beam, at a second level of resolution coarser
than the first level of resolution, the counter providing an approximate
position of the slider assembly relative to the elongate
beam."}}],"PARA":{"LVL":"0","ID":"P-00189","PTEXT":{"PDAT":["33. The
electronic caliper of",",
wherein:"],"CLREF":{"ID":"CLM-00026","PDAT":"claim
26"}}}},{"ID":"CLM-00034","PARA":{"LVL":"0","ID":"P-00190","PTEXT":{"PDAT":["34.
The electronic caliper of",", wherein the counter is responsive at spatial
intervals of at most ###frac14;
cycle."],"CLREF":{"ID":"CLM-00033","PDAT":"claim
33"}}}},{"ID":"CLM-00035","PARA":{"LVL":"0","ID":"P-00191","PTEXT":{"PDAT":["35.
The electronic caliper of",", wherein the inductive area comprises a
plurality of alternating polarity
regions."],"CLREF":{"ID":"CLM-00033","PDAT":"claim
33"}}}},{"ID":"CLM-00036","PARA":{"LVL":"0","ID":"P-00192","PTEXT":{"PDAT":["36.
The electronic caliper of",", wherein the plurality of alternating polarity
regions comprises regions of a surface bounded by at least one conductor
positioned on the surface in a prescribed
pattern."],"CLREF":{"ID":"CLM-00035","PDAT":"claim
35"}}}},{"ID":"CLM-00037","CLMSTEP":[{"LVL":"2","PTEXT":{"PDAT":"supplying
power from a self-contained energy supply source to a drive circuit of the
electronic caliper;"}},{"LVL":"2","PTEXT":{"PDAT":"outputting a drive
signal from the drive circuit in response to a control
signal;"}},{"LVL":"2","PTEXT":{"PDAT":"inducing a current in at least one
flux coupling loop in response to the drive signal, wherein the at least
one flux coupling loop is positioned on one of a slide and an elongated
beam of the electronic caliper, the elongated beam having a measuring axis,
the slide being moveable along the measuring axis, and the at least one
flux coupling loop being arranged along the measuring
axis;"}},{"LVL":"2","PTEXT":{"PDAT":"producing a spatially modulated
time-varying magnetic field with the at least one flux coupling loop in
response to the current, the spatially modulated time-varying magnetic
field extending along the measuring
axis;"}},{"LVL":"2","PTEXT":{"PDAT":"sensing the spatially modulated
time-varying magnetic field using at least one magnetic flux sensor on the
other of the slide and the elongated
beam;"}},{"LVL":"2","PTEXT":{"PDAT":"generating a position signal based on
the sensed field; and"}},{"LVL":"2","PTEXT":{"PDAT":"analyzing the position
signal to generate an output indicative of a relative position of the slide
and the elongated
beam."}}],"PARA":{"LVL":"0","ID":"P-00193","PTEXT":{"PDAT":"37. A method
for operating an electronic caliper,
comprising:"}}},{"ID":"CLM-00038","CLMSTEP":[{"LVL":"2","PTEXT":{"PDAT":"the
spatially modulated time-varying magnetic field is generated and sensed in
a sensing track positioned parallel to the measuring axis;
and"}},{"LVL":"2","PTEXT":{"PDAT":"the spatially modulated time-varying
magnetic field predominates the total magnetic field within the sensing
track."}}],"PARA":{"LVL":"0","ID":"P-00194","PTEXT":{"PDAT":["38. The
method of",", wherein:"],"CLREF":{"ID":"CLM-00037","PDAT":"claim
37"}}}},{"ID":"CLM-00039","CLMSTEP":[{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"a
slide;"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"an elongated beam
having a measuring axis, the slide movable along the measuring
axis:"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"at least one
magnetic field generator, each magnetic field generator responsive to a
drive signal to generate a primary changing magnetic flux in a
corresponding primary flux
region;"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"at least one
operably positionable flux coupling loop associated with at least one of
the at least one magnetic field generator, wherein, for each operably
positionable flux coupling loop, a portion of that flux coupling loop is
positionable within the corresponding primary flux region of the associated
at least one magnetic field generator and, for each operably positionable
flux coupling loop, that portion of that flux coupling loop is responsive
to the primary changing magnetic flux when that portion of that flux
coupling loop is positioned within the corresponding primary flux region to
produce a secondary changing magnetic flux in a portion of that flux
coupling loop that is separated from the corresponding primary flux region;
and"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"at least one magnetic
flux
sensor:"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"wherein:"}}}},{"LVL":"3","PTEXT":{"HIL":[{"ITALIC":{"PDAT":"one
of a"}},{"ITALIC":{"PDAT":"the at least one magnetic flux sensor or
b"}},{"ITALIC":{"PDAT":"the at least one magnetic field generator includes
at least one inductive area extending along the measuring axis, and the
inductive area is spatially modulated along the measuring axis in a pattern
including alternating increases and decreases in width,
and"}}],"PDAT":[")",")"]}},{"LVL":"3","PTEXT":{"HIL":{"ITALIC":{"PDAT":"for
each magnetic flux
sensor:"}}}},{"LVL":"4","PTEXT":{"HIL":{"ITALIC":{"PDAT":"that magnetic
flux sensor is positioned outside the corresponding primary flux region of
at least one magnetic field generator to sense, in at least one associated
operably positionable flux coupling loop, the secondary changing magnetic
flux in the portion of that flux coupling loop that is separated from the
corresponding primary flux region,
and"}}}},{"LVL":"4","PTEXT":{"HIL":{"ITALIC":{"PDAT":{"content":"that
magnetic flux sensor is responsive to the sensed secondary changing
magnetic flux to generate an output signal which is a function of the
relative position between the slide and the elongated
beam.","INS-E":{"ID":"INS-S-00001"}}}}}}],"PARA":{"LVL":"0","ID":"P-00195","PTEXT":{"PDAT":{"content":"39.
An electronic caliper
comprising:","INS-S":{"ID":"INS-S-00001","DATE":"20020101"}}}}},{"ID":"CLM-00040","PARA":{"LVL":"0","ID":"P-00196","PTEXT":{"PDAT":[{"content":"40.
The electronic caliper
of","INS-S":{"ID":"INS-S-00002","DATE":"20020101"}},{"content":", wherein
each inductive area comprises a plurality of alternating polarity
regions.","INS-E":{"ID":"INS-S-00002"}}],"CLREF":{"ID":"CLM-00039","PDAT":"claim
39"}}}},{"ID":"CLM-00041","PARA":{"LVL":"0","ID":"P-00197","PTEXT":{"PDAT":[{"content":"41.
The electronic caliper
of","INS-S":{"ID":"INS-S-00003","DATE":"20020101"}},{"content":", wherein
each pattern of alternating polarity regions comprises regions along a
surface, the regions bounded by at least one conductor positioned on the
surface in a prescribed
pattern.","INS-E":{"ID":"INS-S-00003"}}],"CLREF":{"ID":"CLM-00040","PDAT":"claim
40"}}}},{"ID":"CLM-00042","PARA":{"LVL":"0","ID":"P-00198","PTEXT":{"HIL":[{"ITALIC":{"PDAT":"the
at least one magnetic field generator or
b"}},{"ITALIC":{"PDAT":{"content":"the at least one magnetic flux sensor
which has the at least one inductive area spatially modulated along the
measuring axis is positioned on one of the slide and the elongated beam,
and the at least one operably positionable flux coupling loop is positioned
on the other one of the slide and the elongated
beam.","INS-E":{"ID":"INS-S-00004"}}}}],"PDAT":[{"content":"42. The
electronic caliper of","INS-S":{"ID":"INS-S-00004","DATE":"20020101"}},",
wherein the one of a)",")"],"CLREF":{"ID":"CLM-00039","PDAT":"claim
39"}}}},{"ID":"CLM-00043","PARA":{"LVL":"0","ID":"P-00199","PTEXT":{"HIL":[{"ITALIC":{"PDAT":"the
at least one magnetic field generator and
b"}},{"ITALIC":{"PDAT":{"content":"the at least one magnetic flux sensor is
positioned on either the slide or the elongated
beam.","INS-E":{"ID":"INS-S-00005"}}}}],"PDAT":[{"content":"43. The
electronic caliper of","INS-S":{"ID":"INS-S-00005","DATE":"20020101"}},",
wherein the other of a)",")"],"CLREF":{"ID":"CLM-00042","PDAT":"claim
42"}}}},{"ID":"CLM-00044","PARA":{"LVL":"0","ID":"P-00200","PTEXT":{"PDAT":[{"content":"44.
The electronic caliper
of","INS-S":{"ID":"INS-S-00006","DATE":"20020101"}},{"content":", wherein
in the absence of the at least one associated operably positionable flux
coupling loop, the output signal generated by that associated magnetic flux
sensor is relatively insensitive to the changing magnetic flux in the
corresponding primary flux
region.","INS-E":{"ID":"INS-S-00006"}}],"CLREF":{"ID":"CLM-00039","PDAT":"claim
39"}}}},{"ID":"CLM-00045","PARA":{"LVL":"0","ID":"P-00201","PTEXT":{"PDAT":[{"content":"45.
The electronic caliper
of","INS-S":{"ID":"INS-S-00007","DATE":"20020101"}},{"content":", wherein
the at least one magnetic field generator, the at least one operably
positionable flux coupling loop and the at least one magnetic flux sensor
are fabricated by printed circuit board
processing.","INS-E":{"ID":"INS-S-00007"}}],"CLREF":{"ID":"CLM-00039","PDAT":"claim
39"}}}},{"ID":"CLM-00046","CLMSTEP":[{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"an
energy supply source that outputs a power
supply;"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"a drive circuit
that inputs the power supply and that outputs a drive signal to at least
one of the at least one magnetic field generator during each measurement
cycle; and"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":{"content":"an
analyzing circuit that inputs the output signal from at least one of the at
least one magnetic field sensor, determines the position of the slide
relative to the elongated beam, and outputs a position signal indicative of
the position of the slide relative to the elongated beam at a first level
of
resolution.","INS-E":{"ID":"INS-S-00008"}}}}}}],"PARA":{"LVL":"0","ID":"P-00202","PTEXT":{"PDAT":[{"content":"46.
The electronic caliper
of","INS-S":{"ID":"INS-S-00008","DATE":"20020101"}},", further
comprising:"],"CLREF":{"ID":"CLM-00039","PDAT":"claim
39"}}}},{"ID":"CLM-00047","PARA":{"LVL":"0","ID":"P-00203","PTEXT":{"PDAT":[{"content":"47.
The electronic caliper
of","INS-S":{"ID":"INS-S-00009","DATE":"20020101"}},{"content":", wherein
the drive circuit comprises a capacitor discharged through the at least one
magnetic field
generator.","INS-E":{"ID":"INS-S-00009"}}],"CLREF":{"ID":"CLM-00046","PDAT":"claim
46"}}}},{"ID":"CLM-00048","PARA":{"LVL":"0","ID":"P-00204","PTEXT":{"PDAT":[{"content":"48.
The electronic caliper
of","INS-S":{"ID":"INS-S-00010","DATE":"20020101"}},{"content":", wherein
the capacitor and each of the at least one magnetic field generator form a
resonant
circuit.","INS-E":{"ID":"INS-S-00010"}}],"CLREF":{"ID":"CLM-00047","PDAT":"claim
47"}}}},{"ID":"CLM-00049","PARA":{"LVL":"0","ID":"P-00205","PTEXT":{"PDAT":[{"content":"49.
The electronic caliper
of","INS-S":{"ID":"INS-S-00011","DATE":"20020101"}},{"content":", wherein
the analyzing circuit comprises a counter for counting fractions of cycles
of the at least one output signal output from the at least one magnetic
field sensor at a second level of resolution coarser than the first level
of resolution in response to motion of the slide along the measuring
axis.","INS-E":{"ID":"INS-S-00011"}}],"CLREF":{"ID":"CLM-00046","PDAT":"claim
46"}}}},{"ID":"CLM-00050","CLMSTEP":{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":{"content":"the
analyzing circuit substantially eliminates the influence of signal
components which are third harmonics of the wavelength
W.","INS-E":{"ID":"INS-S-00012"}}}}}},"PARA":{"LVL":"0","ID":"P-00206","PTEXT":{"HIL":{"BOLD":{"PDAT":"3"}},"PDAT":[{"content":"50.
The electronic caliper
of","INS-S":{"ID":"INS-S-00012","DATE":"20020101"}},", wherein each of a
plurality of N magnetic flux sensors, where N is greater than or equal
to",", comprise identical inductive areas spatially modulated along the
measuring axis with a periodic modulation having a wavelength W, and such
inductive areas are offset from each other by a length O###equals;W/N along
the measuring axis; and"],"CLREF":{"ID":"CLM-00046","PDAT":"claim
46"}}}},{"ID":"CLM-00051","PARA":{"LVL":"0","ID":"P-00207","PTEXT":{"HIL":{"BOLD":{"PDAT":"1"}},"PDAT":[{"content":"51.
The electronic caliper
of","INS-S":{"ID":"INS-S-00013","DATE":"20020101"}},", wherein the changing
magnetic flux generated by the at least one magnetic field generator
changes at a rate equivalent to an oscillation frequency of at
least",{"content":"MHz.","INS-E":{"ID":"INS-S-00013"}}],"CLREF":{"ID":"CLM-00039","PDAT":"claim
39"}}}},{"ID":"CLM-00052","PARA":{"LVL":"0","ID":"P-00208","PTEXT":{"PDAT":[{"content":"52.
The electronic caliper
of","INS-S":{"ID":"INS-S-00014","DATE":"20020101"}},{"content":", wherein
the pattern including alternating increases and decreases in width
comprises a periodic pattern having a selected
wavelength.","INS-E":{"ID":"INS-S-00014"}}],"CLREF":{"ID":"CLM-00039","PDAT":"claim
39"}}}},{"ID":"CLM-00053","PARA":{"LVL":"0","ID":"P-00209","PTEXT":{"HIL":{"ITALIC":{"PDAT":{"content":"half
wavelength along the measuring
axis.","INS-E":{"ID":"INS-S-00015"}}}},"PDAT":[{"content":"53. The
electronic caliper of","INS-S":{"ID":"INS-S-00015","DATE":"20020101"}},",
wherein the portion of each operably positionable flux coupling loop
adjacent the periodic pattern spans, at most,
one-"],"CLREF":{"ID":"CLM-00052","PDAT":"claim
52"}}}},{"ID":"CLM-00054","PARA":{"LVL":"0","ID":"P-00210","PTEXT":{"PDAT":[{"content":"54.
The electronic caliper
of","INS-S":{"ID":"INS-S-00016","DATE":"20020101"}},{"content":", wherein a
first plurality of operably positionable flux coupling loops of a first
type are arranged along the measuring axis at a pitch equal to the
wavelength.","INS-E":{"ID":"INS-S-00016"}}],"CLREF":{"ID":"CLM-00052","PDAT":"claim
52"}}}},{"ID":"CLM-00055","PARA":{"LVL":"0","ID":"P-00211","PTEXT":{"HIL":{"ITALIC":{"PDAT":{"content":"half
wavelength from the first plurality of operably positionable flux coupling
loops and at a pitch equal to the wavelength, and the operably positionable
flux coupling loops of the first and second type alternate along the
measuring axis in at least the region adjacent to the periodic
pattern.","INS-E":{"ID":"INS-S-00017"}}}},"PDAT":[{"content":"55. The
electronic caliper of","INS-S":{"ID":"INS-S-00017","DATE":"20020101"}},",
wherein a second plurality of operably positionable flux coupling loops of
a second type are arranged along the measuring axis offset by
one-"],"CLREF":{"ID":"CLM-00054","PDAT":"claim
54"}}}},{"ID":"CLM-00056","PARA":{"LVL":"0","ID":"P-00212","PTEXT":{"PDAT":[{"content":"56.
The electronic caliper
of","INS-S":{"ID":"INS-S-00018","DATE":"20020101"}},{"content":", wherein,
in one of the first or second flux coupling loop types, the induced current
produces the same polarity flux in the portion of an operably positionable
flux coupling loop positionable within the corresponding primary flux
region and in the portion of that flux coupling loop that is separated from
the corresponding primary flux region, and, in the other of the first or
second flux coupling loop types, the induced current produces flux in the
portion of an operably positionable flux coupling loop that is separated
from the corresponding primary flux region which is opposite in polarity to
the flux induced in the portion of that flux coupling loop positionable
within the corresponding primary flux
region.","INS-E":{"ID":"INS-S-00018"}}],"CLREF":{"ID":"CLM-00055","PDAT":"claim
55"}}}},{"ID":"CLM-00057","PARA":{"LVL":"0","ID":"P-00213","PTEXT":{"PDAT":[{"content":"57.
The electronic caliper
of","INS-S":{"ID":"INS-S-00019","DATE":"20020101"}},{"content":", wherein
the first and second flux coupling loop types couple to the same magnetic
field generator region and are configured so that the operable positionable
flux coupling loops of the first type extend in a first direction
perpendicular to the measuring axis to couple to a first magnetic flux
sensor region and the operably positionable flux coupling loops of the
second type extend in an opposite direction perpendicular to the measuring
axis to couple to a second magnetic flux sensor
region.","INS-E":{"ID":"INS-S-00019"}}],"CLREF":{"ID":"CLM-00055","PDAT":"claim
55"}}}},{"ID":"CLM-00058","PARA":{"LVL":"0","ID":"P-00214","PTEXT":{"PDAT":[{"content":"58.
The electronic caliper
of","INS-S":{"ID":"INS-S-00020","DATE":"20020101"}},{"content":", wherein
the first and second flux coupling loop types couple to the same magnetic
flux sensor region, but are configured so that the operably positionable
flux coupling loops of the first type extend in a first direction
perpendicular to the measuring axis to couple to a first magnetic flux
generator region and the operably positionable flux coupling loops of the
second type extend in an opposite direction perpendicular to the measuring
axis to couple to a second magnetic flux generator
region.","INS-E":{"ID":"INS-S-00020"}}],"CLREF":{"ID":"CLM-00055","PDAT":"claim
55"}}}},{"ID":"CLM-00059","PARA":{"LVL":"0","ID":"P-00215","PTEXT":{"HIL":[{"ITALIC":{"PDAT":"the
at least one magnetic flux generator or
b"}},{"ITALIC":{"PDAT":{"content":"the at least one magnetic flux sensor
comprises two similar portions arranged symmetrically on opposite sides of
the other of the at least one magnetic flux generator and the at least one
magnetic flux sensor, such that in absence of the at least one operably
positionable flux coupling loop, the net flux through the magnetic flux
sensor is substantially zero as a result of the symmetric
configuration.","INS-E":{"ID":"INS-S-00021"}}}}],"PDAT":[{"content":"59.
The electronic caliper
of","INS-S":{"ID":"INS-S-00021","DATE":"20020101"}},", wherein
a)",")"],"CLREF":{"ID":"CLM-00039","PDAT":"claim
39"}}}},{"ID":"CLM-00060","PARA":{"LVL":"0","ID":"P-00216","PTEXT":{"PDAT":[{"content":"60.
The electronic caliper
of","INS-S":{"ID":"INS-S-00022","DATE":"20020101"}},{"content":", wherein
the at least one operably positionable flux coupling loop comprises a
plurality of flux coupling loops arranged along the measuring axis and the
measuring range of the sensor is determined by the extent of the plurality
of flux coupling
loops.","INS-E":{"ID":"INS-S-00022"}}],"CLREF":{"ID":"CLM-00039","PDAT":"claim
39"}}}},{"ID":"CLM-00061","PARA":{"LVL":"0","ID":"P-00217","PTEXT":{"PDAT":[{"content":"61.
The electronic caliper
of","INS-S":{"ID":"INS-S-00023","DATE":"20020101"}},{"content":", wherein
each of a plurality of the inductive areas which are spatially modulated
along the measuring axis comprises an area outlined by a patterned
conductor insulated from other patterned conductors, and a plurality of
such inductive areas at least partially
overlap.","INS-E":{"ID":"INS-S-00023"}}],"CLREF":{"ID":"CLM-00039","PDAT":"claim
39"}}}},{"ID":"CLM-00062","PARA":{"LVL":"0","ID":"P-00218","PTEXT":{"HIL":[{"BOLD":{"PDAT":"2"}},{"BOLD":{"PDAT":"2"}},{"BOLD":{"PDAT":"2"}}],"PDAT":[{"content":"62.
The electronic caliper
of","INS-S":{"ID":"INS-S-00024","DATE":"20020101"}},", wherein each of a
plurality of N inductive areas which are spatially modulated along the
measuring axis is identical and is periodically modulated along the
measuring axis with a selected wavelength W, and such inductive areas are
offset from each other by a length O along the measuring axis, where
O###equals;W/","N for N equal to",", and O###equals;W/N for N greater
than",{"content":".","INS-E":{"ID":"INS-S-00024"}}],"CLREF":{"ID":"CLM-00061","PDAT":"claim
61"}}}},{"ID":"CLM-00063","CLMSTEP":[{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"a
slide;"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"an elongated beam
having a measuring axis, the slide movable along the measuring
axis;"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"a low power energy
supply source on the slide capable of providing a power supply to a drive
circuit on the slide;"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"the
drive circuit connected to the power supply and responsive to a control
signal to output an intermittent drive
signal;"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"at least one
magnetic field generator on the slide, each magnetic field generator
responsive to the drive signal to generate a primary changing magnetic flux
in a corresponding primary flux
region;"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"at least one
operable positionable flux coupling loop on the elongated beam associated
with at least one of the at least one magnetic field generator, wherein,
for each operably positionable flux coupling loop, a portion of that flux
coupling loop is positionable within the corresponding primary flux region
of the associated at least one magnetic field generator and, that portion
of that flux coupling loop is responsive to the primary changing magnetic
flux when that portion of that flux coupling loop is positioned within the
corresponding primary flux region to produce a secondary changing magnetic
flux in a portion of that flux coupling loop that is outside the
corresponding primary flux region;
and"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"at least one magnetic
flux sensor on the slide, wherein, for each magnetic flux
sensor:"}}}},{"LVL":"3","PTEXT":{"HIL":{"ITALIC":{"PDAT":"that magnetic
flux sensor is positioned outside the corresponding primary flux region of
at least one magnetic field generator for sensing, in at least one
associated flux coupling loop, the secondary changing magnetic flux in the
portion that is outside the corresponding primary flux region of each at
least one associated flux coupling loop,
and"}}}},{"LVL":"3","PTEXT":{"HIL":{"ITALIC":{"PDAT":"that magnetic flux
sensor is responsive to the sensed secondary changing magnetic flux to
generate an output signal which is a function of the relative position
between the magnetic flux sensor and the at least one associated flux
coupling loop;
and"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":{"content":"an
analyzing circuit on the slide responsive to the output signal from at
least one magnetic flux sensor to output an output signal indicative of the
position of the slide relative to the elongated beam at a first level of
resolution.","INS-E":{"ID":"INS-S-00025"}}}}}}],"PARA":{"LVL":"0","ID":"P-00219","PTEXT":{"PDAT":{"content":"63.
An electronic caliper
comprising:","INS-S":{"ID":"INS-S-00025","DATE":"20020101"}}}}},{"ID":"CLM-00064","PARA":{"LVL":"0","ID":"P-00220","PTEXT":{"PDAT":[{"content":"64.
The electronic caliper
of","INS-S":{"ID":"INS-S-00026","DATE":"20020101"}},{"content":", wherein
the drive circuit comprises a capacitor that discharges through the
magnetic field
generator.","INS-E":{"ID":"INS-S-00026"}}],"CLREF":{"ID":"CLM-00063","PDAT":"claim
63"}}}},{"ID":"CLM-00065","PARA":{"LVL":"0","ID":"P-00221","PTEXT":{"PDAT":[{"content":"65.
The electronic caliper
of","INS-S":{"ID":"INS-S-00027","DATE":"20020101"}},{"content":", wherein
the capacitor and each of the at least one magnetic field generator operate
as a resonant
circuit.","INS-E":{"ID":"INS-S-00027"}}],"CLREF":{"ID":"CLM-00064","PDAT":"claim
64"}}}},{"ID":"CLM-00066","PARA":{"LVL":"0","ID":"P-00222","PTEXT":{"HIL":{"BOLD":{"PDAT":"1"}},"PDAT":[{"content":"66.
The electronic caliper
of","INS-S":{"ID":"INS-S-00028","DATE":"20020101"}},", wherein the primary
changing magnetic flux changes at a rate equivalent to an oscillation
frequency of at least",{"content":"MHz in response to the intermittent
drive
signal.","INS-E":{"ID":"INS-S-00028"}}],"CLREF":{"ID":"CLM-00064","PDAT":"claim
64"}}}},{"ID":"CLM-00067","PARA":{"LVL":"0","ID":"P-00223","PTEXT":{"PDAT":[{"content":"67.
The electronic caliper
of","INS-S":{"ID":"INS-S-00029","DATE":"20020101"}},{"content":", wherein
the intermittent drive signal comprises at least one pulse
signal.","INS-E":{"ID":"INS-S-00029"}}],"CLREF":{"ID":"CLM-00064","PDAT":"claim
64"}}}},{"ID":"CLM-00068","PARA":{"LVL":"0","ID":"P-00224","PTEXT":{"PDAT":[{"content":"68.
The electronic caliper
of","INS-S":{"ID":"INS-S-00030","DATE":"20020101"}},{"content":", wherein
the analyzing circuit determines changes in the relative position at a
coarse level of resolution during each pulse interval, and determines the
relative position at a finer level of resolution once during a plurality of
pulse
intervals.","INS-E":{"ID":"INS-S-00030"}}],"CLREF":{"ID":"CLM-00067","PDAT":"claim
67"}}}},{"ID":"CLM-00069","PARA":{"LVL":"0","ID":"P-00225","PTEXT":{"PDAT":[{"content":"69.
The electronic caliper
of","INS-S":{"ID":"INS-S-00031","DATE":"20020101"}},{"content":", wherein
the analyzing circuit includes synchronous sampling means for sampling the
output signal from at least one magnetic flux sensor synchronously with the
pulse
signal.","INS-E":{"ID":"INS-S-00031"}}],"CLREF":{"ID":"CLM-00067","PDAT":"claim
67"}}}},{"ID":"CLM-00070","PARA":{"LVL":"0","ID":"P-00226","PTEXT":{"PDAT":[{"content":"70.
The electronic caliper
of","INS-S":{"ID":"INS-S-00032","DATE":"20020101"}},{"content":", wherein
the synchronous sampling uses sample timing based on an expected time delay
between the pulsed signal and a peak in a response to a resonant circuit
formed by the pulse generator components and the magnetic field generator
components.","INS-E":{"ID":"INS-S-00032"}}],"CLREF":{"ID":"CLM-00069","PDAT":"claim
69"}}}},{"ID":"CLM-00071","CLMSTEP":[{"LVL":"2","PTEXT":{"HIL":[{"ITALIC":{"PDAT":"at
least one of a"}},{"ITALIC":{"PDAT":"each of the at least one magnetic flux
sensor, and b"}},{"ITALIC":{"PDAT":"each of the at least one magnetic field
generator includes at least one inductive area extending along the
measuring axis, and the at least one inductive area is spatially modulated
along the measuring axis in a pattern including alternating increases and
decreases in
width;"}}],"PDAT":[")",")"]}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":"the
output signal from each of the at least one magnetic flux sensor exhibits
spatial cycles which are a function of a relative position between that
magnetic flux sensor and the at least one associated flux coupling loop;
and"}}}},{"LVL":"2","PTEXT":{"HIL":{"ITALIC":{"PDAT":{"content":"the
analyzing circuit comprises a counter for counting fractions of cycles of
the output signal from the at least one magnetic flux sensor in response to
motion of the slide along the elongated beam, at a second level of
resolution coarser than the first level of resolution, the counter
providing an approximate position of the slider assembly relative to the
elongate
beam.","INS-E":{"ID":"INS-S-00033"}}}}}}],"PARA":{"LVL":"0","ID":"P-00227","PTEXT":{"PDAT":[{"content":"71.
The electronic caliper
of","INS-S":{"ID":"INS-S-00033","DATE":"20020101"}},",
wherein"],"CLREF":{"ID":"CLM-00063","PDAT":"claim
63"}}}},{"ID":"CLM-00072","PARA":{"LVL":"0","ID":"P-00228","PTEXT":{"HIL":[{"BOLD":{"PDAT":"1"}},{"BOLD":{"PDAT":"4"}}],"PDAT":[{"content":"72.
The electronic caliper
of","INS-S":{"ID":"INS-S-00034","DATE":"20020101"}},", wherein the counter
is responsive at spatial intervals of at most {fraction
(","/",{"content":")}
cycle.","INS-E":{"ID":"INS-S-00034"}}],"CLREF":{"ID":"CLM-00071","PDAT":"claim
71"}}}},{"ID":"CLM-00073","PARA":{"LVL":"0","ID":"P-00229","PTEXT":{"PDAT":[{"content":"73.
The electronic caliper
of","INS-S":{"ID":"INS-S-00035","DATE":"20020101"}},{"content":", wherein
the inductive area comprises a plurality of alternating polarity
regions.","INS-E":{"ID":"INS-S-00035"}}],"CLREF":{"ID":"CLM-00071","PDAT":"claim
71"}}}},{"ID":"CLM-00074","PARA":{"LVL":"0","ID":"P-00230","PTEXT":{"PDAT":[{"content":"74.
The electronic caliper
of","INS-S":{"ID":"INS-S-00036","DATE":"20020101"}},{"content":", wherein
the plurality of alternating polarity regions comprises regions of a
surface bounded by at least one conductor positioned on the surface in a
prescribed
pattern.","INS-E":{"ID":"INS-S-00036"}}],"CLREF":{"ID":"CLM-00073","PDAT":"claim
73"}}}}]}},"SDOAB":{"BTEXT":{"PARA":{"LVL":"0","ID":"P-00001","PTEXT":{"PDAT":"An
electronic caliper having a reduced offset position transducer that uses
two sets of coupling loops on a scale to inductively couple a transmitter
winding on a read head on a slide to one or more receiver windings on the
read head. The transmitter winding generates a primary magnetic field. The
transmitter winding is inductively coupled to first loop portions of first
and second sets of coupling loops by a magnetic field. Second loop portions
of the first and second sets of coupling loops are interleaved and generate
secondary magnetic fields. A receiver winding is formed in a periodic
pattern of alternating polarity loops and is inductively coupled to the
second loop portions of the first and second sets of coupling loops by the
secondary magnetic fields. Depending on the relative position between the
read head and the scale, each polarity loop of the receiver winding is
inductively coupled to a second loop portion of either the first or second
set of coupling loops. The relative positions of the first and second loop
portions of the first and second sets of coupling loops are periodic and
dependent on the relative position of the coupling loops on the
scale."}}}},"SDOBI":{"B700":{"B745":{"B748US":{"PDAT":"2859"},"B746":{"PARTY-US":{"NAM":{"SNM":{"STEXT":{"PDAT":"Bennett"}},"FNM":{"PDAT":"G.
Bradley"}}}}},"B720":{"B721":[{"PARTY-US":{"ADR":{"STATE":{"PDAT":"WA"},"CITY":{"PDAT":"Kirkland"}},"NAM":{"SNM":{"STEXT":{"PDAT":"Andermo"}},"FNM":{"PDAT":"Nils
I."}}}},{"PARTY-US":{"ADR":{"STATE":{"PDAT":"WA"},"CITY":{"PDAT":"Bellevue"}},"NAM":{"SNM":{"STEXT":{"PDAT":"Masreliez"}},"FNM":{"PDAT":"Karl
G."}}}}]},"B730":{"B732US":{"PDAT":"03"},"B731":{"PARTY-US":{"ADR":{"CITY":{"PDAT":"Kawasaki"},"CTRY":{"PDAT":"JP"}},"NAM":{"ONM":{"STEXT":{"PDAT":"Mitutoyo
Corporation"}}}}}},"B740":{"B741":{"PARTY-US":{"NAM":{"ONM":{"STEXT":{"PDAT":"Oliff
###amp; Berridge,
PLC"}}}}}}},"B100":{"B190":{"PDAT":"US"},"B130":{"PDAT":"E1"},"B110":{"DNUM":{"PDAT":"RE037490"}},"B140":{"DATE":{"PDAT":"20020101"}}},"B600":{"B640":{"PARENT-US":{"PPUB":{"DOC":{"DATE":{"PDAT":"19990511"},"KIND":{"PDAT":"00"},"CTRY":{"PDAT":"US"},"DNUM":{"PDAT":"05901458"}}},"CDOC":{"DOC":{"DNUM":{"PDAT":"09/527518"}}},"PDOC":{"DOC":{"DATE":{"PDAT":"19971121"},"KIND":{"PDAT":"00"},"CTRY":{"PDAT":"US"},"DNUM":{"PDAT":"08/975651"}}},"PSTA":{"PDAT":"00"}}}},"B200":{"B211US":{"PDAT":"09"},"B220":{"DATE":{"PDAT":"20000316"}},"B210":{"DNUM":{"PDAT":"09527518"}}},"B500":{"B510":{"B511":{"PDAT":"G01B
702"},"B516":{"PDAT":"7"}},"B580":{"B582":[{"PDAT":"33706"},{"PDAT":"33708"},{"PDAT":"33783"},{"PDAT":"33784"},{"PDAT":"33810"},{"PDAT":"33811"},{"PDAT":"33812"},{"PDAT":"32420715"},{"PDAT":"32420717"},{"PDAT":"32420724"},{"PDAT":"324244"},{"PDAT":"324249"},{"PDAT":"324259"},{"PDAT":"324664"}]},"B520":{"B521":{"PDAT":"33810"},"B522":[{"PDAT":"33784"},{"PDAT":"33708"},{"PDAT":"32420724"}]},"B560":{"B561":[{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19740500"},"KIND":{"PDAT":"A"},"DNUM":{"PDAT":"3812481"}},"PARTY-US":{"NAM":{"SNM":{"STEXT":{"PDAT":"Stedtnitz"}}}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19841100"},"KIND":{"PDAT":"A"},"DNUM":{"PDAT":"4483077"}},"PARTY-US":{"NAM":{"SNM":{"STEXT":{"PDAT":"Matsumoto
et
al."}}}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19930700"},"KIND":{"PDAT":"A"},"DNUM":{"PDAT":"5225830"}},"PARTY-US":{"NAM":{"SNM":{"STEXT":{"PDAT":"Andermo
et
al."}}}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19931000"},"KIND":{"PDAT":"A"},"DNUM":{"PDAT":"5253431"}},"PARTY-US":{"NAM":{"SNM":{"STEXT":{"PDAT":"Smith"}}}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19941100"},"KIND":{"PDAT":"A"},"DNUM":{"PDAT":"5363034"}},"PARTY-US":{"NAM":{"SNM":{"STEXT":{"PDAT":"Tada
et
al."}}}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19950800"},"KIND":{"PDAT":"A"},"DNUM":{"PDAT":"5442865"}},"PARTY-US":{"NAM":{"SNM":{"STEXT":{"PDAT":"Wallrafen"}}}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19970400"},"KIND":{"PDAT":"A"},"DNUM":{"PDAT":"5625239"}},"PARTY-US":{"NAM":{"SNM":{"STEXT":{"PDAT":"Persson
et
al."}}}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19980800"},"KIND":{"PDAT":"A"},"DNUM":{"PDAT":"5798640"}},"PARTY-US":{"NAM":{"SNM":{"STEXT":{"PDAT":"Gier
et
al."}}}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19980900"},"KIND":{"PDAT":"A"},"DNUM":{"PDAT":"5804963"}},"PARTY-US":{"NAM":{"SNM":{"STEXT":{"PDAT":"Meyer"}}}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19981100"},"KIND":{"PDAT":"A"},"DNUM":{"PDAT":"5841274"}},"PARTY-US":{"NAM":{"SNM":{"STEXT":{"PDAT":"Masreliez
et
al."}}}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19981100"},"KIND":{"PDAT":"A"},"DNUM":{"PDAT":"5841275"}},"PARTY-US":{"NAM":{"SNM":{"STEXT":{"PDAT":"Spies"}}}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19910300"},"CTRY":{"PDAT":"DE"},"DNUM":{"PDAT":"4009977"}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19910800"},"CTRY":{"PDAT":"EP"},"DNUM":{"PDAT":"0443148"}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19920900"},"CTRY":{"PDAT":"EP"},"DNUM":{"PDAT":"0501453"}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19960500"},"CTRY":{"PDAT":"EP"},"DNUM":{"PDAT":"0709648"}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19951100"},"CTRY":{"PDAT":"WO"},"DNUM":{"PDAT":"WO
95/31696"}}}},{"CITED-BY-OTHER":"","PCIT":{"DOC":{"DATE":{"PDAT":"19970500"},"CTRY":{"PDAT":"WO"},"DNUM":{"PDAT":"WO
97/19323"}}}}]},"B570":{"B578US":{"PDAT":"39"},"B577":{"PDAT":"74"}},"B540":{"STEXT":{"PDAT":"Electronic
caliper using a reduced offset induced current position
transducer"}},"B590":{"B597US":"","B596":{"PDAT":"20"},"B595":{"PDAT":"13"}}}},"STATUS":"Build
20020101","DTD":"2.5","SDODR":{"EMI":[{"ALT":"embedded
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image","ID":"EMI-D00013","FILE":"USRE037490-20020101-D00013.TIF"}],"ID":"DRAWINGS"},"SDODE":{"DRWDESC":{"BTEXT":{"H":{"LVL":"1","STEXT":{"PDAT":"BRIEF
DESCRIPTION OF THE
DRAWINGS"}},"PARA":[{"LVL":"0","ID":"P-00057","PTEXT":{"PDAT":"The
preferred embodiments of this invention will be described in detail, with
reference to the following figures,
wherein:"}},{"LVL":"0","ID":"P-00058","PTEXT":{"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
1"},"PDAT":"shows an electronic caliper using an induced current position
transducer having undesirable extraneous signal offset
components;"}},{"LVL":"0","ID":"P-00059","PTEXT":{"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
2"},{"ID":"DRAWINGS","PDAT":"FIG. 1"}],"PDAT":["is a cross-sectional view
of the caliper
of",";"]}},{"LVL":"0","ID":"P-00060","PTEXT":{"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
3"},{"ID":"DRAWINGS","PDAT":"FIG. 1"}],"PDAT":["shows the induced current
position transducer of the electronic caliper
of",";"]}},{"LVL":"0","ID":"P-00061","PTEXT":{"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
4A"},{"ID":"DRAWINGS","PDAT":"FIG. 3"}],"PDAT":["shows the
position-dependent output of the positive polarity loops
of",";"]}},{"LVL":"0","ID":"P-00062","PTEXT":{"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
4B"},{"ID":"DRAWINGS","PDAT":"FIG. 3"}],"PDAT":["shows the
position-dependent output of the negative polarity loops
of",";"]}},{"LVL":"0","ID":"P-00063","PTEXT":{"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
4C"},{"ID":"DRAWINGS","PDAT":"FIG. 3"}],"PDAT":["shows the net
position-dependent output of the positive and negative polarity loops
of",";"]}},{"LVL":"0","ID":"P-00064","PTEXT":{"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
5"},"PDAT":"shows an electronic caliper of this invention using a reduced
offset high accuracy induced current position
transducer;"}},{"LVL":"0","ID":"P-00065","PTEXT":{"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
6"},"PDAT":"shows a first embodiment of the scale for the reduced offset
induced current position transducer of the electronic caliper of this
invention;"}},{"LVL":"0","ID":"P-00066","PTEXT":{"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
7"},"PDAT":"shows a first embodiment of the read head for the reduced
offset induced current position transducer of the electronic caliper of
this
invention;"}},{"LVL":"0","ID":"P-00067","PTEXT":{"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
8"},"PDAT":"shows a second embodiment of the read-head for the reduced
offset induced current position transducer of this
invention."}},{"LVL":"0","ID":"P-00068","PTEXT":{"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
9"},{"ID":"DRAWINGS","PDAT":"FIG. 8"}],"PDAT":["shows the signal amplitudes
as a function of the relative position of the scale and read-head
of",";"]}},{"LVL":"0","ID":"P-00069","PTEXT":{"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
10"},{"ID":"DRAWINGS","PDAT":"FIG. 8"}],"PDAT":["shows a schematic vector
phase diagram for the three phase windings
of",";"]}},{"LVL":"0","ID":"P-00070","PTEXT":{"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
11A"},"PDAT":"shows a third embodiment of the scale for the reduced offset
induced current position transducer of this
invention;"}},{"LVL":"0","ID":"P-00071","PTEXT":{"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
11B"},{"ID":"DRAWINGS","PDAT":"FIG. 11A"}],"PDAT":["shows a first portion
of the scale of","in greater
detail;"]}},{"LVL":"0","ID":"P-00072","PTEXT":{"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
11C"},{"ID":"DRAWINGS","PDAT":"FIG. 11A"}],"PDAT":["shows a second portion
of the scale of","in greater
detail;"]}},{"LVL":"0","ID":"P-00073","PTEXT":{"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
11D"},{"ID":"DRAWINGS","PDAT":"FIG. 11A"}],"PDAT":["shows a third
embodiment of the read head usable with the scale
of",";"]}},{"LVL":"0","ID":"P-00074","PTEXT":{"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
12A"},"PDAT":"shows a cross-sectional view of the first embodiment of the
reduced offset induced current position transducer of this
invention;"}},{"LVL":"0","ID":"P-00075","PTEXT":{"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
12B"},"PDAT":"shows a cross-sectional view of the second embodiment of the
reduced offset induced current position transducer of this
invention;"}},{"LVL":"0","ID":"P-00076","PTEXT":{"HIL":{"BOLD":{"PDAT":"8"}},"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
13"},"PDAT":["is a block diagram of the read head shown in FIG.","and its
associated signal processing circuits;
and"]}},{"LVL":"0","ID":"P-00077","PTEXT":{"HIL":{"BOLD":{"PDAT":"13"}},"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
14"},"PDAT":["is a timing diagram for one of the three channels of the
electronic unit shown in
FIG.","."]}}]}},"DETDESC":{"BTEXT":{"H":{"LVL":"1","STEXT":{"PDAT":"DETAILED
DESCRIPTION OF PREFERRED
EMBODIMENTS"}},"PARA":[{"LVL":"0","ID":"P-00078","PTEXT":{"HIL":[{"BOLD":{"PDAT":"200"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"206"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"206"}},{"BOLD":{"PDAT":"206"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"202"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
5"},"PDAT":["As shown in",", an inductive caliper","includes an elongated
beam",". The elongated beam","is a rigid or semi-rigid bar having a
generally rectangular cross section. A groove","is formed in an upper
surface of the elongated beam",". An elongated measuring scale","is rigidly
bonded to the elongated beam","in the groove",". The groove","is formed in
the beam","at a depth about equal to the thickness of the scale",". Thus,
the top surface of the scale","is very nearly coplanar with the top edges
of
beam","."]}},{"LVL":"0","ID":"P-00079","PTEXT":{"HIL":[{"BOLD":{"PDAT":"208"}},{"BOLD":{"PDAT":"210"}},{"BOLD":{"PDAT":"212"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"216"}},{"BOLD":{"PDAT":"218"}},{"BOLD":{"PDAT":"220"}},{"BOLD":{"PDAT":"214"}},{"BOLD":{"PDAT":"208"}},{"BOLD":{"PDAT":"216"}},{"BOLD":{"PDAT":"210"}},{"BOLD":{"PDAT":"218"}},{"BOLD":{"PDAT":"222"}},{"BOLD":{"PDAT":"210"}},{"BOLD":{"PDAT":"218"}}],"PDAT":["A
pair of laterally projecting, fixed jaws","and","are integrally formed near
a first end","of the beam",". A corresponding pair of laterally projecting
movable jaws","and","are formed on a slider assembly",". The outside
dimensions of an object are measured by placing the object between a pair
of engagement surfaces","on the jaws","and",". Similarly, the inside
dimensions of an object are measured by placing the jaws","and","within an
object. The engagement surfaces","of the jaws","and","are positioned to
contact the surfaces on the object to be
measured."]}},{"LVL":"0","ID":"P-00080","PTEXT":{"HIL":[{"BOLD":{"PDAT":"222"}},{"BOLD":{"PDAT":"214"}},{"BOLD":{"PDAT":"214"}},{"BOLD":{"PDAT":"208"}},{"BOLD":{"PDAT":"216"}},{"BOLD":{"PDAT":"222"}},{"BOLD":{"PDAT":"210"}},{"BOLD":{"PDAT":"218"}},{"BOLD":{"PDAT":"200"}}],"PDAT":["The
engagement surfaces","and","are positioned so that when the engagement
surfaces","of the jaws","and","are contacting each other, the engagement
surfaces","of the jaws","and","are aligned with each other. In this
position, the zero position, both the outside and inside dimensions
measured by the caliper","should be
zero."]}},{"LVL":"0","ID":"P-00081","PTEXT":{"HIL":[{"BOLD":{"PDAT":"200"}},{"BOLD":{"PDAT":"224"}},{"BOLD":{"PDAT":"220"}},{"BOLD":{"PDAT":"224"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"226"}},{"BOLD":{"PDAT":"224"}},{"BOLD":{"PDAT":"226"}},{"BOLD":{"PDAT":"228"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"200"}},{"BOLD":{"PDAT":"228"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"224"}},{"BOLD":{"PDAT":"226"}},{"BOLD":{"PDAT":"200"}}],"PDAT":["The
caliper","also includes a depth bar","which is attached to the slider
assembly",". The depth bar","projects longitudinally from the beam","and
terminates at an engagement end",". The length of the depth bar","is such
that the engagement end","is flush with a second end","of the beam","when
the caliper","is at the zero position. By resting the second end","of the
beam","on a surface in which a hole is formed and extending the depth
bar","into the hole until the end","touches the bottom of the hole, the
caliper","is able to measure the depth of the
hole."]}},{"LVL":"0","ID":"P-00082","PTEXT":{"HIL":[{"BOLD":{"PDAT":"208"}},{"BOLD":{"PDAT":"216"}},{"BOLD":{"PDAT":"210"}},{"BOLD":{"PDAT":"218"}},{"BOLD":{"PDAT":"224"}},{"BOLD":{"PDAT":"234"}},{"BOLD":{"PDAT":"236"}},{"BOLD":{"PDAT":"200"}},{"BOLD":{"PDAT":"230"}},{"BOLD":{"PDAT":"232"}},{"BOLD":{"PDAT":"236"}},{"BOLD":{"PDAT":"230"}},{"BOLD":{"PDAT":"260"}},{"BOLD":{"PDAT":"220"}},{"BOLD":{"PDAT":"232"}},{"BOLD":{"PDAT":"234"}}],"PDAT":["Whether
a measurement is made using the outside measuring jaws","and",", the inside
measuring jaws","and",", or the depth bar",", the measured dimension is
displayed on a conventional digital display",", which is mounted in a
cover","of the caliper",". A pair of push button switches","and","are also
mounted in the cover",". The switch","turns on and off a signal processing
and display electronic circuit","of the slider assembly",". The switch","is
used to reset the display","to
zero."]}},{"LVL":"0","ID":"P-00083","PTEXT":{"HIL":[{"BOLD":{"PDAT":"220"}},{"BOLD":{"PDAT":"238"}},{"BOLD":{"PDAT":"240"}},{"BOLD":{"PDAT":"240"}},{"BOLD":{"PDAT":"242"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"220"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"200"}},{"BOLD":{"PDAT":"244"}},{"BOLD":{"PDAT":"246"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"220"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"224"}},{"BOLD":{"PDAT":"248"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"248"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"224"}},{"BOLD":{"PDAT":"224"}},{"BOLD":{"PDAT":"248"}},{"BOLD":{"PDAT":"250"}},{"BOLD":{"PDAT":"250"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"228"}},{"BOLD":{"PDAT":"250"}},{"BOLD":{"PDAT":"220"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"228"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
5"},"PDAT":["As shown in",", the slider assembly","includes a base","with a
guiding edge",". The guiding edge","contacts a side edge","of the elongated
beam","when the slider assembly","straddles the elongated beam",". This
ensures accurate operation of the caliper",". A pair of screws","bias a
resilient pressure bar","against a mating edge of the beam","to eliminate
free play between the slider assembly","and the elongated beam",". The
depth bar","is inserted into a depth bar groove","formed on an underside of
the elongated beam",". The depth bar groove","extends along the underside
of the elongated beam","to provide clearance for the depth bar",". The
depth bar","is held in the depth bar groove","by an end stop",". The end
stop","is attached to the underside of the beam","at the second end",". The
end stop","also prevents the slider assembly","from inadvertently
disengaging from the elongated beam","at the second end","during
operation."]}},{"LVL":"0","ID":"P-00084","PTEXT":{"HIL":[{"BOLD":{"PDAT":"220"}},{"BOLD":{"PDAT":"252"}},{"BOLD":{"PDAT":"238"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"238"}},{"BOLD":{"PDAT":"252"}},{"BOLD":{"PDAT":"252"}},{"BOLD":{"PDAT":"254"}},{"BOLD":{"PDAT":"254"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"260"}},{"BOLD":{"PDAT":"254"}},{"BOLD":{"PDAT":"256"}},{"BOLD":{"PDAT":"236"}},{"BOLD":{"PDAT":"254"}},{"BOLD":{"PDAT":"260"}}],"PDAT":["The
slider assembly","also includes a read head assembly","mounted on the
base","above the elongated beam",". Thus, the base","and read head
assembly","move as a unit. The read head assembly","includes a
substrate",", such as a conventional printed circuit board. The
substrate","bears an inductive read head","on its lower surface. A signal
processing and display electronic circuit","is mounted on an upper surface
of the substrate",". A resilient seal","is compressed between the
cover","and the substrate","to prevent contamination of the signal
processing and display electronic
circuit","."]}},{"LVL":"0","ID":"P-00085","PTEXT":{"HIL":[{"BOLD":{"PDAT":"220"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"202"}},{"BOLD":{"PDAT":"270"}},{"BOLD":{"PDAT":"262"}},{"BOLD":{"PDAT":"268"}},{"BOLD":{"PDAT":"270"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"266"}}],"PDAT":["The
slider assembly","carries the read head","so that it is slightly separated
from the beam","by an air gap","formed between the insulative
coatings","and",". The air gap","is preferably on the order of 0.5 mm.
Together, the read head","and the flux couplers","form an inductive
transducer."]}},{"LVL":"0","ID":"P-00086","PTEXT":{"HIL":{"BOLD":{"PDAT":"200"}},"FGREF":{"ID":"DRAWINGS","PDAT":"FIGS.
6 and 7"},"PDAT":["show a first embodiment of the reduced-offset
incremental induced current position transducer","used in the electronic
caliper of this invention, which produces an output type usually referred
to as ###ldquo;incremental###rdquo;. ###ldquo;Incremental###rdquo; output
is defined as a cyclic output which is repeated according to a
design-related increment of transducer
displacement."]}},{"LVL":"0","ID":"P-00087","PTEXT":{"HIL":[{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"200"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"276"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
6"},"PDAT":["In particular,","shows a first embodiment of the reduced
offset scale","of the transducer",". The reduced-offset scale","includes a
first plurality of coupling loops","interleaved with a second plurality of
coupling loops",". Each of the coupling loops","and","is electrically
isolated from the others of the first and second plurality of coupling
loops","and","."]}},{"LVL":"0","ID":"P-00088","PTEXT":{"HIL":[{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"278"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"282"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"284"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"288"}}],"PDAT":["Each
of the first plurality of coupling loops","includes a first loop
portion","and a second loop portion","connected by a pair of connecting
conductors",". Similarly, each of the second plurality of coupling
loops","includes a first loop portion","and a second loop
portion","connected by a pair of connecting
conductors","."]}},{"LVL":"0","ID":"P-00089","PTEXT":{"HIL":[{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"278"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"272"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"272"}},{"BOLD":{"PDAT":"282"}},{"BOLD":{"PDAT":"272"}},{"BOLD":{"PDAT":"278"}},{"BOLD":{"PDAT":"280"}}],"PDAT":["In
the first plurality of coupling loops",", the first loop portions","are
arranged along one lateral edge of the scale","and are arrayed along a
measuring axis",". The second loop portions","are arranged along the center
of the scale","and are arrayed along the measuring axis",". The connecting
conductors","extend perpendicularly to the measuring axis","to connect the
first loop portions","to the second loop
portions","."]}},{"LVL":"0","ID":"P-00090","PTEXT":{"HIL":[{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"284"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"272"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"272"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"288"}},{"BOLD":{"PDAT":"272"}},{"BOLD":{"PDAT":"284"}},{"BOLD":{"PDAT":"286"}}],"PDAT":["Similarly,
in the second plurality of coupling loops",", the first loop portions","are
arranged along a second lateral edge of the scale","and arrayed along the
measuring axis",". The second loop portions","are arranged along the center
of the scale","along the measuring axis",", interleaved with the second
loop portions","of the second coupling loops",". The connecting
conductors","extend generally perpendicularly to the measuring axis","to
connect the first loop portions","to the second loop
portions","."]}},{"LVL":"0","ID":"P-00091","PTEXT":{"HIL":[{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"200"}},{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"272"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"SB":{"PDAT":"1"}},{"BOLD":{"PDAT":"272"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
7"},"PDAT":["As shown in",", the read head","of the transducer","includes a
transmitter winding","having a first transmitter winding portion","A and a
second transmitter winding portion","B. The first transmitter winding
portion","A is provided at a first lateral edge of the read head","while
the second transmitter winding portion","B is provided at the other lateral
edge of the read head",". Each of the first and second transmitter winding
portions","A and","B have the same long dimension extending along the
measuring axis",". Furthermore, each of the first and second transmitter
winding portions","A and","B have a short dimension that extends a distance
d","in a direction perpendicular to the measuring
axis","."]}},{"LVL":"0","ID":"P-00092","PTEXT":{"HIL":[{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"294"}},{"BOLD":{"PDAT":"294"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}}],"PDAT":["The
terminals","A and","B of the transmitter winding","are connected to the
transmitter drive signal generator",". The transmitter drive signal
generator","outputs a time-varying drive signal to the transmitter winding
terminal","A. Thus a time-varying current flows through the transmitter
winding","from the transmitter winding terminal","A to the transmitter
winding
terminal","B."]}},{"LVL":"0","ID":"P-00093","PTEXT":{"HIL":[{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}}],"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
7"},{"ID":"DRAWINGS","PDAT":"FIG. 7"},{"ID":"DRAWINGS","PDAT":"FIG.
7"},{"ID":"DRAWINGS","PDAT":"FIG. 7"}],"PDAT":["In response, the first
transmitter winding portion","A generates a magnetic field that rises up
out of the plane of","inside the first transmitter winding portion","A and
descends into the plane of","outside the loop formed by the first
transmitter winding portion","A. In contrast, the second transmitter
winding portion","B generates a primary magnetic field that rises up out of
the plane of","outside the loop formed by the second transmitter winding
portion","B and descends into the plane of","inside the loop formed by the
second transmitter winding
portion","B."]}},{"LVL":"0","ID":"P-00094","PTEXT":{"HIL":[{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"278"}},{"BOLD":{"PDAT":"284"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
7"},"PDAT":["A current is then induced in the coupling loops","and","that
counteracts the change of magnetic field. Thus, the induced current in each
of the coupling loop sections","and","flows in a direction opposite to the
current flowing in the respective adjacent portions of the transmitter
loops","A and","B. As shown in","adjacent ones of the second loop
portions","and","in the center section of the scale have loop currents
having opposite polarities. Thus, a secondary magnetic field is created
having field portions of opposite polarity periodically distributed along
the center section of the scale. The wavelength ###lgr; of the periodic
secondary magnetic field is equal to the distance between successive second
loop
portions","(or",")."]}},{"LVL":"0","ID":"P-00095","PTEXT":{"HIL":[{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"3"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"300"}},{"BOLD":{"PDAT":"302"}},{"BOLD":{"PDAT":"258"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
3"},"PDAT":["The read head","also includes first and second receiver
windings","and","that are generally identical to the first and second
receiver windings","and","shown in FIG.",". In particular, similarly to the
first and second receiver windings","and","shown in",", the first and
second receiver windings","and","are each formed by a plurality of
sinusoidally-shaped loop segments","and","formed on opposite sides of an
insulating layer of the printed circuit board forming the read
head","."]}},{"LVL":"0","ID":"P-00096","PTEXT":{"HIL":[{"BOLD":{"PDAT":"300"}},{"BOLD":{"PDAT":"302"}},{"BOLD":{"PDAT":"304"}},{"BOLD":{"PDAT":"306"}},{"BOLD":{"PDAT":"308"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"SB":{"PDAT":"2"}}],"PDAT":["The
loop segments","and","are linked through feed-throughs","to form
alternating positive polarity loops","and negative polarity loops","in each
of the first and second receiver windings","and",". The receiver
windings","and","are positioned in the center of the read head","between
the first and second transmitter portions","A and","B. Each of the first
and second receiver windings","and","extends a distance d","in the
direction perpendicular to the measuring
axis."]}},{"LVL":"0","ID":"P-00097","PTEXT":{"HIL":[{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"SB":{"PDAT":"3"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}}],"PDAT":["Extraneous
(position independent and scale independent) coupling from the transmitter
loops to the receiver loops is generally avoided in this configuration.
That is, the primary magnetic fields generated by the first and second
transmitter portions","A and","B point in opposite directions in the
vicinity of the first and second receiver windings","and",". Thus, the
primary magnetic fields counteract each other in the area occupied by the
first and second receiver windings","and",". Ideally, the primary magnetic
fields completely counteract each in this area. The first and second
receiver windings","and","are spaced equal distances d","from the inner
portions of the first and second transmitter winding portions","A and","B.
Thus, the magnetic fields generated by each of the first and second
transmitter winding portions","A and","B in the portion of the read
head","occupied by the first and second receiver windings","and","are in
symmetric opposition and the associated inductive effects effectively
cancel each other out. The net voltage induced in the first and second
receiver windings","and","by extraneous direct coupling to the first and
second transmitter winding portions","A and","B is reduced to a first
extent by positioning the transmitter windings away from the receiver
windings. Secondly, the symmetric design effectively reduces the net
extraneous coupling to
zero."]}},{"LVL":"0","ID":"P-00098","PTEXT":{"HIL":[{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"278"}},{"BOLD":{"PDAT":"272"}},{"BOLD":{"PDAT":"310"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"278"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"278"}},{"SB":{"PDAT":"1"}},{"BOLD":{"PDAT":"272"}}],"PDAT":["Each
of the first plurality of coupling loops","is arranged at a pitch equal to
a wavelength ###lgr; of the first and second receiver windings","and",".
Furthermore, the first loop portions","each extends a distance along the
measuring axis","which is as close as possible to the wavelength ###lgr;
while still providing an insulating space","between adjacent ones of the
first loop portions","and",". In addition, the first loop
portions","and","extend the distance d","in the direction perpendicular to
the measuring
axis","."]}},{"LVL":"0","ID":"P-00099","PTEXT":{"HIL":[{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"284"}},{"BOLD":{"PDAT":"310"}},{"BOLD":{"PDAT":"284"}},{"BOLD":{"PDAT":"284"}},{"SB":{"PDAT":"1"}},{"BOLD":{"PDAT":"272"}}],"PDAT":["Similarly,
the second plurality of coupling loops","are also arranged at a pitch equal
to the wavelength ###lgr;. The first loop portions","also extend as close
as possible to each other along the measuring axis to the wavelength
###lgr; while providing the space","between adjacent ones of the first loop
portions",". The first loop portions","also extend the distance d","in the
direction perpendicular to the measuring
axis","."]}},{"LVL":"0","ID":"P-00100","PTEXT":{"HIL":[{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"312"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"7"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"SB":{"PDAT":"2"}},{"BOLD":{"PDAT":"272"}}],"PDAT":["The
second loop portions","and","of the first and second pluralities of
coupling loops","and","are also arranged at a pitch equal to the wavelength
###lgr;. However, each of the second loop portions","and","extends along
the measuring axis as close as possible to only one-half the wavelength
###lgr;. An insulating space","is provided between each adjacent pair of
second loop portions","and","of the first and second pluralities of
coupling loops","and",", as shown in FIG.",". Thus, the second loop
portions","and","of the first and second pluralities of coupling
loops","and","are interleaved along the length of the scale",". Finally,
each of the second loop portions","and","extends the distance d","in the
direction perpendicular to the measuring
axis","."]}},{"LVL":"0","ID":"P-00101","PTEXT":{"HIL":[{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"SB":{"PDAT":"3"}},{"BOLD":{"PDAT":"278"}},{"BOLD":{"PDAT":"284"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"278"}},{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"284"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}}],"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
7"},{"ID":"DRAWINGS","PDAT":"FIG. 7"}],"PDAT":["As shown in",", the second
loop portions","and","are spaced the distance d","from the corresponding
first loop portions","and",". Accordingly, when the read head","is placed
in proximity to the scale",", as shown in",", the first transmitter winding
portion","A aligns with the first loop portions","of the first plurality of
coupling loops",". Similarly, the second transmitter winding portion","B
aligns with the first loop portions","of the second plurality of coupling
loops",". Finally, the first and second receiver windings","and","align
with the second loop portions","and","of the first and second coupling
loops","and",". As will be apparent from the preceding and the following
discussions, the area enclosed by the second loop portions","and","define a
sensing track extending parallel to the measuring axis, and that
substantially all of the effective magnetic field passing through the
sensing track is due solely to the current flow in the second loop
portions."]}},{"LVL":"0","ID":"P-00102","PTEXT":{"HIL":[{"BOLD":{"PDAT":"294"}},{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}}],"PDAT":["In
operation, a time-varying drive signal is output by the transmitter drive
signal generator","to the transmitter winding terminal","A. Thus, the first
transmitter winding portion","A generates a first changing magnetic field
having a first direction while the second transmitter winding portion","B
generates a second magnetic field in a second direction that is opposite to
the first direction. This second magnetic field has a field strength that
is equal to a field strength of the first magnetic field generated by the
first transmitter winding
portion","A."]}},{"LVL":"0","ID":"P-00103","PTEXT":{"HIL":[{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"276"}}],"PDAT":["Each
of the first plurality of coupling loops","is inductively coupled to the
first transmitter winding portion","A by the first magnetic field generated
by the first transmitter winding portion","A. Thus, an induced current
flows clockwise through each of the first plurality of coupling loops",".
At the same time the second plurality of coupling loops","is inductively
coupled to the second transmitter winding portion","B by the second
magnetic field generated by the second transmitter winding portion","B.
This induces a counterclockwise current to flow in each of the second
plurality of coupling loops",". That is, the currents through the second
portions","and","of the coupling loops","and","flow in opposite
directions."]}},{"LVL":"0","ID":"P-00104","PTEXT":{"HIL":[{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"272"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}}],"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
7"},{"ID":"DRAWINGS","PDAT":"FIG. 7"}],"PDAT":["The clockwise flowing
current in each of the second portions","of the first coupling
loops","generates a third magnetic field that depends into the plane
of","within the second portions",". In contrast, the counterclockwise
flowing currents in the second loop portions","of the second coupling
loops","generate a fourth magnetic field that rises out of the plane
of","within the second loop portions","of the second coupling loops",".
Thus, a net alternating magnetic field is formed along the measuring
axis",". This net alternating magnetic field has a wavelength which is
equal to the wavelength ###lgr; of the first and second receiver
windings","and","."]}},{"LVL":"0","ID":"P-00105","PTEXT":{"HIL":[{"BOLD":{"PDAT":"306"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"308"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"306"}},{"BOLD":{"PDAT":"308"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"306"}},{"BOLD":{"PDAT":"308"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}}],"PDAT":["Accordingly,
when the positive polarity loops","of the first receiver winding","are
aligned with either the second loop portions","or",", the negative polarity
loops","of the first receiver winding","are aligned with the other of the
second loop portions","or",". This is also true when the positive polarity
loops","and the negative polarity loops","of the second receiver
winding","are aligned with the second loop portions","and",". Because the
alternating magnetic field generated by the second loop portions","and","is
spatially modulated at the same wavelength as the spatial modulation of the
first and second receiver windings","and",", the EMF generated in each of
the positive and negative polarity loops","and","when aligned with the
second loop portions","is equal and opposite to the EMF generated when they
are aligned with the second loop
portions","."]}},{"LVL":"0","ID":"P-00106","PTEXT":{"HIL":[{"BOLD":{"PDAT":"306"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"308"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"306"}},{"BOLD":{"PDAT":"308"}},{"SB":{"PDAT":"o"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
4C"},"PDAT":["Thus, the net output of the positive polarity loops",", as
the read head","moves relative to the scale","is a sinusoidal function of
the relative position of the read head along the scale and the offset
component of the output signal due to extraneous coupling is nominally
zero. Similarly, the net output from the negative polarity loops",", as the
read head","moves relative to the scale",", is also sinusoidal and centered
on the position axis. The EMF output from the positive polarity loops","and
the negative polarity loops","are in phase. They thus generate a net
position-dependent output signal corresponding to",", but without the DC
offset
V","."]}},{"LVL":"0","ID":"P-00107","PTEXT":{"HIL":[{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"138"}},{"BOLD":{"PDAT":"140"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"314"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"314"}}],"PDAT":["Finally,
the first and second receiver windings","and",", like the first and second
receiver windings","and",", are in quadrature. Thus, the output signal
generated by the first receiver winding","and output to the receiver signal
processing circuit","is 90 degrees out of phase with the signal output by
the second receiver winding","to the receiver signal processing
circuit","."]}},{"LVL":"0","ID":"P-00108","PTEXT":{"HIL":[{"BOLD":{"PDAT":"314"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"316"}},{"BOLD":{"PDAT":"316"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"204"}}],"PDAT":["The
receiver signal processing circuit","inputs and samples the output signals
from the first and second receiver windings","and",", converts the signals
to digital values and outputs them to the control unit",". The control
unit","processes these digitized output signals to determine the relative
position between the read head","and the scale","within a wavelength
###lgr;."]}},{"LVL":"0","ID":"P-00109","PTEXT":{"HIL":[{"BOLD":{"PDAT":"306"}},{"BOLD":{"PDAT":"308"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}}],"PDAT":["It
should be appreciated that, with a suitable feed-through arrangement,
either the positive polarity loops","or the negative polarity loops","could
be reduced to zero width perpendicular to the measuring axis (becoming
effectively simple conducting elements between the adjacent loops). In this
case, the first and second receiver windings","and","become unipolar flux
receivers, introducing an increased sensitivity to external fields, and
reducing their output signal amplitude to half that of the previously
described embodiment (due to the eliminated loop
area)."]}},{"LVL":"0","ID":"P-00110","PTEXT":{"HIL":[{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}}],"PDAT":["However,
the modified design retains many inventive benefits. The net extraneous
flux through the loops is still nominally zero due to the symmetric
transmitter winding configuration. The output signal from each receiver
winding","and","still swings from a maximum positive value to a maximum
negative value with nominally zero offset. The degree of output signal
change per unit of displacement, for a given measuring range, is still very
high, due to the complementary periodic structure of the scale elements and
receiver
windings."]}},{"LVL":"0","ID":"P-00111","PTEXT":{"HIL":[{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"316"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"316"}},{"BOLD":{"PDAT":"316"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"204"}}],"PDAT":["Based
on the nature of the quadrature output from the first and second receiver
windings","and",", the control unit","is able to determine the direction of
relative motion between the read head","and the scale",". The control
unit","counts the number of partial or full ###ldquo;incremental###rdquo;
wavelengths ###lgr; traversed, by signal processing methods well-known to
those skilled in the art and disclosed herein and in the incorporated
references. The control unit","uses that number and the relative position
within a wavelength ###lgr; to output the relative position between the
read head","and the scale","from a set
origin."]}},{"LVL":"0","ID":"P-00112","PTEXT":{"HIL":[{"BOLD":{"PDAT":"316"}},{"BOLD":{"PDAT":"294"}},{"BOLD":{"PDAT":"314"}},{"BOLD":{"PDAT":"294"}},{"BOLD":{"PDAT":"316"}}],"PDAT":["The
control unit","also outputs control signals to the transmitter drive signal
generator","to generate the time-varying transmitter drive signal. It
should be appreciated that any of the signal generating and processing
circuits shown in U.S. patent application Ser. No. 08/441,769, filed May
16, 1995, U.S. patent application Ser. No. 08/645,483, filed May 13, 1996
and U.S. patent application Ser. No. 08/788,469, filed Jan. 29, 1997 hereby
incorporated by reference, can be used to implement the receiver signal
processing circuit",", the transmitter drive signal generator","and the
control unit",". Thus, these circuits will not be described in further
detail
herein."]}},{"LVL":"0","ID":"P-00113","PTEXT":{"HIL":[{"BOLD":{"PDAT":"6"}},{"BOLD":{"PDAT":"318"}},{"BOLD":{"PDAT":"320"}},{"BOLD":{"PDAT":"322"}}],"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
8"},{"ID":"DRAWINGS","PDAT":"FIG. 9"}],"PDAT":["shows a second embodiment
of a read head that can be used with a scale according to FIG.",". The
receiver in this version of the read head has three receiver
windings",",","and",". The receiver windings are offset from each other
along the measurement axis by ###frac13; of the wavelength ###lgr;.","shows
the signal functions from the three receivers as a function of the position
along the measurement
axis."]}},{"LVL":"0","ID":"P-00114","PTEXT":{"PDAT":"It should be
appreciated that perfectly sinusoidal output functions are difficult to
achieve in practice, and that deviations from a perfect sinusoidal output
contain spatial harmonics of the fundamental wavelength of the transducer.
Therefore, the three phase configuration of this second embodiment of the
reduced-offset induced current position transducer has a significant
advantage over the first embodiment of the reduced offset induced current
position transducer, in that the third harmonic content in the separate
receiver windings###apos; signal can be largely eliminated as a source of
position measurement
error."}},{"LVL":"0","ID":"P-00115","PTEXT":{"HIL":[{"BOLD":{"PDAT":"318"}},{"BOLD":{"PDAT":"320"}},{"BOLD":{"PDAT":"322"}},{"SB":{"PDAT":"R"}},{"SB":{"PDAT":"S"}},{"SB":{"PDAT":"T"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
10"},"PDAT":["Eliminating the third harmonic is accomplished by combining
the outputs of the receiver windings as shown in",", where the three
windings are connected in a star configuration and the signals used for
determining position are taken between the corners of the star. This can
also be accomplished by measuring each of the output signals independently
from the receiver windings",",","and",", and then combining them
computationally in a corresponding way in a digital signal processing
circuit. The following equations outline how the third harmonic component
is eliminated by suitably combining the original three phase signals,
designated as U",", U",", and
U","."]}},{"LVL":"0","ID":"P-00116","PTEXT":{"CWU":{"MATH-US":{"EMI":{"ALT":"embedded
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msp;"}}}}}],"mstyle":{"mtext":"###emsp;"}},{"mo":["###it;","###it;","###it;"],"mrow":{"mo":["(",")"],"mrow":{"mn":"2","mo":["###it;","###it;"],"mfrac":{"mrow":{"mn":"3","mo":"###it;","mi":"x"},"mi":"##lambda;"},"mi":"###pi;"}},"mi":"sin","mstyle":{"mtext":"###emsp;"},"msub":{"mn":"3","mi":"A"}}]},"mstyle":{"mtext":"###emsp;"}}}}]}}},"MATHEMATICA":{"ALT":"mathematica
file","ID":"MATHEMATICA-00001","FILE":"USRE037490-20020101-M00001.NB"},"ID":"MATH-US-00001"}},"PDAT":"Assume
each of the unprocessed phase signals contains the fundamental sinusoidal
signal plus the third harmonic signal, with equal amplitude in the three
phases,
then:"}},{"LVL":"0","ID":"P-00117","PTEXT":{"CWU":{"MATH-US":{"EMI":{"ALT":"embedded
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new signals by pair-wise subtracting the above-outlined signals from each
other eliminates the third harmonic to
provide:"}},{"LVL":"0","ID":"P-00118","PTEXT":{"HIL":[{"SB":{"PDAT":"S"}},{"SB":{"PDAT":"T"}}],"CWU":{"MATH-US":{"EMI":{"ALT":"embedded
image","ID":"EMI-M00003","FILE":"USRE037490-20020101-M00003.TIF"},"MATHML":{"math":{"mtable":{"mtr":[{"mtd":{"mrow":{"mo":"\u003d","mrow":{"mo":["\u003d","###it;"],"mrow":[{"mo":"-","msub":[{"mi":["V","S"]},{"mi":["V","T"]}]},{"mo":["###it;","###it;","###it;"],"mrow":{"mo":["(",")"],"mrow":{"mo":"-","mrow":[{"mo":["###it;","###it;"],"mrow":{"mo":["(",")"],"mrow":{"mo":"-","mrow":{"mn":"2","mo":["###it;","###it;","###it;"],"mfrac":{"mi":["x","##lambda;"]},"mi":"###pi;","mstyle":{"mtext":"###emsp;"}},"mfrac":{"mn":"6","mrow":{"mn":"2","mo":"###it;","mi":"###pi;"}}}},"mi":"cos","mstyle":{"mtext":"###emsp;"}},{"mo":["###it;","###it;"],"mrow":{"mo":["(",")"],"mrow":{"mo":"+","mrow":{"mn":"2","mo":["###it;","###it;","###it;"],"mfrac":{"mi":["x","##lambda;"]},"mi":"###pi;","mstyle":{"mtext":"###emsp;"}},"mfrac":{"mn":"6","mrow":{"mn":"2","mo":"###it;","mi":"###pi;"}}}},"mi":"cos","mstyle":{"mtext":"###emsp;"}}]}},"msqrt":{"mn":"3"},"mstyle":{"mtext":"###emsp;"},"msub":{"mn":"0","mi":"A"}}],"mstyle":{"mtext":"###emsp;"}},"msub":{"mi":["V","Q"]}}}},{"mtd":{"mrow":{"mo":["\u003d","###it;"],"mrow":{"mo":"\u003d","mrow":[{"mn":["2","2"],"mo":["###it;","","###it;","###it;","###it;","###it;","###it;","###it;","###it;","###it;","###it;"],"mrow":{"mo":["(",")"],"mrow":{"mo":"-","mfrac":{"mn":"6","mrow":{"mn":"2","mo":"###it;","mi":"###pi;"}}}},"msqrt":{"mn":"3"},"mfrac":{"mi":["x","##lambda;"]},"mi":["sin","###pi;","sin"],"mstyle":[{"mtext":"###emsp;"},{"mtext":"###emsp;"},{"mtext":"###emsp;"}],"msub":{"mn":"0","mi":"A"}},{"mn":["3","2"],"mo":["###it;","###it;","###it;","###it;","###it;","###it;","###it;","###it;"],"mfrac":{"mi":["x","##lambda;"]},"mi":["sin","###pi;"],"mstyle":[{"mtext":"###emsp;"},{"mtext":"###emsp;"},{"mtext":"###emsp;"}],"msub":{"mn":"0","mi":"A"}}]},"mstyle":{"mtext":"###emsp;"}}}}]}}},"MATHEMATICA":{"ALT":"mathematica
file","ID":"MATHEMATICA-00003","FILE":"USRE037490-20020101-M00003.NB"},"ID":"MATH-US-00003"}},"PDAT":["To
get quadrature signals for position calculation in the same way, V","and
V","are
combined:"]}},{"LVL":"0","ID":"P-00119","PTEXT":{"CWU":{"MATH-US":{"EMI":{"ALT":"embedded
image","ID":"EMI-M00004","FILE":"USRE037490-20020101-M00004.TIF"},"MATHML":{"math":{"mrow":{"mo":"\u003d","mrow":{"mo":["","###it;","###it;"],"mrow":{"mo":["(",")"],"mrow":{"mn":"2","mo":["###it;","###it;","###it;"],"mfrac":{"mi":["x","##lambda;"]},"mi":"###pi;","mstyle":{"mtext":"###emsp;"}}},"msqrt":{"mn":"3"},"mi":"tan","mstyle":{"mtext":"###emsp;"}},"mfrac":{"mrow":{"mo":"-","msub":{"mi":["V","R"]}},"msub":{"mi":["V","Q"]}}}}},"MATHEMATICA":{"ALT":"mathematica
file","ID":"MATHEMATICA-00004","FILE":"USRE037490-20020101-M00004.NB"},"ID":"MATH-US-00004"}},"PDAT":"After
identifying the applicable quarter-wavelength position quadrant within the
incremental wavelength, the interpolated position within the quarter
wavelength is then calculated
by:"}},{"LVL":"0","ID":"P-00120","PTEXT":{"CWU":{"MATH-US":{"EMI":{"ALT":"embedded
image","ID":"EMI-M00005","FILE":"USRE037490-20020101-M00005.TIF"},"MATHML":{"math":{"mrow":{"mo":"\u003d","mrow":{"mo":["","###it;","###it;"],"mrow":{"mo":["(",")"],"mfrac":{"mrow":{"mo":"*","mrow":{"mo":"-","msub":{"mi":["V","R"]}},"msqrt":{"mn":"3"}},"msub":{"mi":["V","Q"]}}},"msup":{"mn":"1","mi":"tan"},"mfrac":{"mrow":{"mn":"2","mo":"###it;","mi":"###pi;"},"mi":"##lambda;"},"mstyle":{"mtext":"###emsp;"}},"mi":"x"}}},"MATHEMATICA":{"ALT":"mathematica
file","ID":"MATHEMATICA-00005","FILE":"USRE037490-20020101-M00005.NB"},"ID":"MATH-US-00005"}},"PDAT":"Solving
for x:"}},{"LVL":"0","ID":"P-00121","PTEXT":{"PDAT":"The position
calculated this way using the output from three phase receiver windings
will not contain any error from third harmonic components in the receiver
output signal functions, to the extent that the outputs from all three
receiver windings have the same third harmonic characteristics, which is
generally the case for practical devices. Also, if the receiver signals are
amplified in preamplifiers in the electronic unit, the measurement error
caused by certain distortion errors in those electronic preamplifiers will
be canceled by the above described signal processing in the three phase
configuration."}},{"LVL":"0","ID":"P-00122","PTEXT":{"HIL":[{"BOLD":{"PDAT":"490"}},{"BOLD":{"PDAT":"496"}},{"BOLD":{"PDAT":"498"}},{"BOLD":{"PDAT":"458"}},{"BOLD":{"PDAT":"404"}},{"BOLD":{"PDAT":"474"}},{"BOLD":{"PDAT":"476"}},{"BOLD":{"PDAT":"404"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIGS.
11A-11D"},"PDAT":["show a third embodiment of the read head and scale for
the reduced offset induced current position transducer of the linear scale
of this invention. This embodiment contains only one transmitter winding
loop",", which is placed on one side of the receiver windings","and","on
the read head",". The scale","is a two layer printed circuit board (PCB).
Pattern forming coupling loops","and","are arrayed on the scale","along the
measurement
axis."]}},{"LVL":"0","ID":"P-00123","PTEXT":{"HIL":[{"BOLD":{"PDAT":"474"}},{"BOLD":{"PDAT":"478"}},{"BOLD":{"PDAT":"482"}},{"BOLD":{"PDAT":"480"}},{"BOLD":{"PDAT":"478"}},{"BOLD":{"PDAT":"480"}},{"BOLD":{"PDAT":"478"}},{"BOLD":{"PDAT":"480"}},{"BOLD":{"PDAT":"476"}},{"BOLD":{"PDAT":"484"}},{"BOLD":{"PDAT":"488"}},{"BOLD":{"PDAT":"486"}},{"BOLD":{"PDAT":"484"}},{"BOLD":{"PDAT":"486"}},{"BOLD":{"PDAT":"484"}},{"BOLD":{"PDAT":"486"}}],"PDAT":["Each
coupling loop","includes a first loop portion","which is connected by
connection lines","to a second loop portion",". The first and second loop
portions","and","are connected so that an induced current produces the same
polarity field in the first loop portion","and the second loop portion",".
Each coupling loop","includes a first loop portion","which is connected by
connection lines","to a second loop portion",". The first and second loop
portions","and","are connected so that an induced current produces fields
having opposite polarities in the first and second loop
portions","and","."]}},{"LVL":"0","ID":"P-00124","PTEXT":{"HIL":[{"BOLD":{"PDAT":"474"}},{"BOLD":{"PDAT":"476"}},{"BOLD":{"PDAT":"404"}},{"BOLD":{"PDAT":"404"}},{"BOLD":{"PDAT":"504"}},{"BOLD":{"PDAT":"474"}},{"BOLD":{"PDAT":"476"}}],"FGREF":[{"ID":"DRAWINGS","PDAT":"FIGS.
11B and 11C"},{"ID":"DRAWINGS","PDAT":"FIG.
11B"},{"ID":"DRAWINGS","PDAT":"FIG. 11C"}],"PDAT":["The detailed
construction of the coupling loops","and","is shown in",".","shows a first
conductor pattern provided on a first one of the layers of the PCB forming
the scale",".","shows a second construction pattern provided on a second
one of the layers of the PCB forming the scale",". The individual portions
of the first and second patterns formed on the first and second layers are
connected via the feed-throughs","of the PCB to form the coupling
loops","and","."]}},{"LVL":"0","ID":"P-00125","PTEXT":{"HIL":[{"BOLD":{"PDAT":"458"}},{"BOLD":{"PDAT":"490"}},{"BOLD":{"PDAT":"496"}},{"BOLD":{"PDAT":"498"}},{"BOLD":{"PDAT":"496"}},{"BOLD":{"PDAT":"498"}},{"BOLD":{"PDAT":"490"}},{"BOLD":{"PDAT":"478"}},{"BOLD":{"PDAT":"484"}},{"BOLD":{"PDAT":"490"}},{"BOLD":{"PDAT":"7"}}],"PDAT":["The
read head","is formed by a second PCB and includes a transmitter loop","and
first and second receiver windings","and",". The first and second receiver
windings","and","are in this embodiment in a two-phase configuration. This
embodiment could also use the three-phase configuration previously
disclosed. The transmitter loop","encloses an area that covers the first
loop portions","and","over the length of the read head. The transmitter
loop","is excited in the same way as described previously in conjunction
with
FIG.","."]}},{"LVL":"0","ID":"P-00126","PTEXT":{"HIL":[{"BOLD":{"PDAT":"478"}},{"BOLD":{"PDAT":"484"}},{"BOLD":{"PDAT":"474"}},{"BOLD":{"PDAT":"476"}},{"BOLD":{"PDAT":"490"}},{"BOLD":{"PDAT":"490"}},{"BOLD":{"PDAT":"490"}},{"BOLD":{"PDAT":"478"}},{"BOLD":{"PDAT":"484"}},{"BOLD":{"PDAT":"474"}},{"BOLD":{"PDAT":"476"}},{"BOLD":{"PDAT":"480"}},{"BOLD":{"PDAT":"474"}},{"BOLD":{"PDAT":"486"}},{"BOLD":{"PDAT":"476"}},{"BOLD":{"PDAT":"488"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
11D"},"PDAT":["The first loop portions","and","of the coupling
loops","and","under the transmitter loop","respond to the primary magnetic
field generated by the transmitter","with an induced EMF that causes a
current and magnetic field that counteracts the primary magnetic field
produced in the transmitter winding",". When the transmitter winding
current flows counter-clockwise, as shown in",", the induced current in the
first loop portions","and","of the coupling loops","and","flows
counterclockwise. The current in the second loop portions","of the coupling
loops","also flows clockwise. However, the current in the second loop
portions","of the coupling loops","flow counter-clockwise because of the
crossed connections","described
above."]}},{"LVL":"0","ID":"P-00127","PTEXT":{"HIL":[{"BOLD":{"PDAT":"480"}},{"BOLD":{"PDAT":"486"}},{"BOLD":{"PDAT":"496"}},{"BOLD":{"PDAT":"498"}},{"BOLD":{"PDAT":"458"}},{"BOLD":{"PDAT":"480"}},{"BOLD":{"PDAT":"486"}},{"BOLD":{"PDAT":"496"}},{"BOLD":{"PDAT":"498"}}],"PDAT":["Therefore,
the array of second loop portions","and","produces a secondary magnetic
field with regions of opposite polarity periodically repeating along the
scale under the receiver windings","and","of the read head unit",". The
secondary magnetic field has a wavelength ###lgr; equal to the period
length for successive ones of the second loop portions",", which is also
equal to the period length for successive ones of the second loop
portions",". The receiver loops of the first and second
windings","and","are designed to have the same wavelength ###lgr; as the
scale
pattern."]}},{"LVL":"0","ID":"P-00128","PTEXT":{"HIL":[{"BOLD":{"PDAT":"496"}},{"BOLD":{"PDAT":"498"}},{"BOLD":{"PDAT":"458"}},{"BOLD":{"PDAT":"404"}},{"BOLD":{"PDAT":"490"}},{"BOLD":{"PDAT":"280"}},{"BOLD":{"PDAT":"286"}},{"BOLD":{"PDAT":"480"}},{"BOLD":{"PDAT":"486"}},{"BOLD":{"PDAT":"490"}}],"FGREF":[{"ID":"DRAWINGS","PDAT":"FIGS.
6 and 7"},{"ID":"DRAWINGS","PDAT":"FIG. 7"}],"PDAT":["Hence, the receiver
loops of the first and second receiver windings","and","will exhibit an
induced EMF which produces a signal voltage whose amplitude will follow a
periodic function with wavelength ###lgr; when the read head","is moved
along the scale",". Thus, except for the distinction of the single
transmitter loop",", this embodiment functions in the manner previously
described for the embodiment shown in",". Similar to the previous
discussion of second loop portions","and","of",", the total area enclosed
by the second loop portions","and","define a sensing track extending
parallel to the measuring axis. In this case, the effective magnetic field
within the sensing track includes some effect due to coupling to the fringe
of the field produced by the transmitter winding",". However, the current
flow in the second loop portions produces a field in the sensing track that
predominates over any other
field."]}},{"LVL":"0","ID":"P-00129","PTEXT":{"HIL":[{"BOLD":{"PDAT":"7"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"292"}}],"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
12A"},{"ID":"DRAWINGS","PDAT":"FIG. 12A"},{"ID":"DRAWINGS","PDAT":"FIG.
12A"}],"PDAT":["shows a cross-section of an inductive read head according
to the first embodiment of this invention shown in FIG.",".","illustrates
how the primary magnetic field caused by the current in the transmitter
loop","A encircles the conductors and partly crosses through the receiver
loops","and",".","also shows how the primary magnetic field caused by the
current in the transmitter loop","B passes through the receiver
loops","and","in the opposite direction from the primary magnetic field
caused by the transmitter
loop","A."]}},{"LVL":"0","ID":"P-00130","PTEXT":{"HIL":[{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"292"}},{"BOLD":{"PDAT":"296"}},{"BOLD":{"PDAT":"298"}},{"BOLD":{"PDAT":"3"}}],"PDAT":["Thus,
the resulting net magnetic field through the first and second receiver
windings","and","will be very close to zero and the extraneous direct
coupling from the transmitter loops","A and","B to the first and second
receiver windings","and","will be nullified. Experience and theoretical
calculations show an improvement in the ratio of useful to extraneous
signal components by a factor of more than 100 relative to the embodiment
shown in
FIG.","."]}},{"LVL":"0","ID":"P-00131","PTEXT":{"HIL":[{"BOLD":{"PDAT":"11"}},{"BOLD":{"PDAT":"490"}},{"BOLD":{"PDAT":"496"}},{"BOLD":{"PDAT":"498"}},{"BOLD":{"PDAT":"490"}},{"BOLD":{"PDAT":"496"}},{"BOLD":{"PDAT":"498"}}],"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
12B"},{"ID":"DRAWINGS","PDAT":"FIG. 12B"}],"PDAT":["shows a cross-section
of an inductive read head according to the third embodiment of this
invention shown in FIG.","D.","illustrates how the primary magnetic field
caused by the current in the transmitter loop","encircles the conductors
and partly crosses through the first and second receiver loops","and",".
Although this case fails to nullify the extraneous direct coupling, as
provided in the first preferred embodiment, it still reduces the extraneous
direct coupling by virtue of the separation of the transmitter loop","and
the first and second receiver
windings","and","."]}},{"LVL":"0","ID":"P-00132","PTEXT":{"HIL":[{"BOLD":{"PDAT":"496"}},{"BOLD":{"PDAT":"498"}},{"BOLD":{"PDAT":"3"}}],"PDAT":["Furthermore,
the secondary magnetic field having alternating polarities is provided in
the vicinity of the first and second receiver windings","and",". This
eliminates other sources of offset. According to experience and theoretical
calculations, the third embodiment shows an improvement in the ratio of
useful to extraneous signal components by a factor of about 10 relative to
the embodiment shown in
FIG.","."]}},{"LVL":"0","ID":"P-00133","PTEXT":{"HIL":[{"BOLD":{"PDAT":"474"}},{"BOLD":{"PDAT":"476"}},{"BOLD":{"PDAT":"496"}},{"BOLD":{"PDAT":"498"}},{"BOLD":{"PDAT":"490"}},{"BOLD":{"PDAT":"496"}},{"BOLD":{"PDAT":"498"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
11A"},"PDAT":["It should be appreciated that the previous embodiments may
be modified in certain aspects, while retaining many of their inventive
benefits. For example, the coupling loops","(or",") of","may be eliminated,
while other aspects of this configuration remain the same. In this case,
the secondary magnetic field provided in the vicinity of the first and
second receiver windings","and","does not have a pattern of alternating
polarities, as in the third embodiment. However, this design still reduces
the extraneous direct coupling between transmitter and receiver windings by
virtue of the separation of the transmitter loop","and the first and second
receiver
windings","and","."]}},{"LVL":"0","ID":"P-00134","PTEXT":{"HIL":[{"BOLD":{"PDAT":"474"}},{"BOLD":{"PDAT":"476"}},{"BOLD":{"PDAT":"474"}},{"BOLD":{"PDAT":"476"}},{"BOLD":{"PDAT":"496"}},{"BOLD":{"PDAT":"498"}},{"BOLD":{"PDAT":"478"}},{"BOLD":{"PDAT":"484"}},{"BOLD":{"PDAT":"490"}},{"BOLD":{"PDAT":"480"}},{"BOLD":{"PDAT":"486"}},{"BOLD":{"PDAT":"496"}},{"BOLD":{"PDAT":"498"}},{"BOLD":{"PDAT":"478"}},{"BOLD":{"PDAT":"484"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
11D"},"PDAT":["Furthermore, the use of multiple coupling loops provides the
benefit of averaging out the error contributions of small, but significant,
random deviations in segments of the winding configurations due to
imperfect fabrication processes. Also, even if the coupling loops","(or",")
are eliminated, the fundamental operation of the transducer is still based
on a moving structured field, defined by the coupling loops","(or",")
providing the primary excitation for the first and second receiver
windings","and",". It should also be noted that the vertical sections of
the first loop portions","and","shown in","could be bridged by horizontal
conductors at the top and bottom (not shown). In this case, the multiple
coupling loops form a single coupling loop with a single elongated portion
under the transmitter winding",", and multiple serially connected loop
portions","and","under the windings","and",". Thus, the moving structured
field is still maintained, although the function of the first coupling loop
portions","and","is now provided by a single continuous
winding."]}},{"LVL":"0","ID":"P-00135","PTEXT":{"HIL":[{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"474"}},{"BOLD":{"PDAT":"476"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
3"},"PDAT":["In contrast, in the embodiment shown in",", a spatially static
uniform field provided the primary excitation for the first and second
receiver windings","and",". The receiver winding output signals are based
on how this uniform field is affected by moving elements which disturb the
uniform excitation field in the vicinity of the first and second receiver
windings","and",". The moving structured field excitation approach of this
invention provides an inherently superior signal, even if the coupling
loops","(or",") are
eliminated."]}},{"LVL":"0","ID":"P-00136","PTEXT":{"HIL":[{"BOLD":{"PDAT":"200"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"8"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"13"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
13"},"PDAT":["shows a block diagram of the second embodiment of the reduced
offset induced current position transducer","using the three phase read
head","shown in FIG.",". Only the essential portions of the signal
processing circuit needed to determine the position of the read
head","relative to the scale","are shown in
FIG.","."]}},{"LVL":"0","ID":"P-00137","PTEXT":{"HIL":[{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"295"}},{"BOLD":{"PDAT":"294"}},{"BOLD":{"PDAT":"295"}},{"BOLD":{"PDAT":"324"}},{"BOLD":{"PDAT":"326"}},{"SB":{"PDAT":"DD"}},{"BOLD":{"PDAT":"328"}},{"BOLD":{"PDAT":"330"}},{"SB":{"PDAT":"1"}},{"BOLD":{"PDAT":"324"}},{"BOLD":{"PDAT":"326"}},{"BOLD":{"PDAT":"330"}},{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"330"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
13"},"PDAT":["As shown in",", the transmitter winding","is connected to a
signal generator circuit","of the transmitter drive signal generator",".
The signal generator circuit","includes a first switch","serially connected
to a second switch","between ground and a power supply voltage V","from an
energy source",". One terminal of a capacitor","is connected to a node
N","between the first and second switches","and",". A second plate of the
capacitor","is connected to the terminal","A of the transmitter winding",".
The second terminal","B of the transmitter winding","is connected to
ground. This, the transmitter winding","forms the inductor in a LC resonant
circuit with the
capacitor","."]}},{"LVL":"0","ID":"P-00138","PTEXT":{"HIL":[{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"318"}},{"BOLD":{"PDAT":"320"}},{"BOLD":{"PDAT":"322"}},{"BOLD":{"PDAT":"318"}},{"BOLD":{"PDAT":"320"}},{"BOLD":{"PDAT":"322"}},{"BOLD":{"PDAT":"332"}},{"BOLD":{"PDAT":"318"}},{"BOLD":{"PDAT":"334"}},{"BOLD":{"PDAT":"320"}},{"BOLD":{"PDAT":"336"}},{"BOLD":{"PDAT":"322"}},{"BOLD":{"PDAT":"338"}}],"PDAT":["The
transmitter winding","is indirectly inductively coupled via the coupling
loops","and","formed on the scale","to the first-third receiver
windings",",","and",". The receiver windings",",","and","are connected to a
sample and hold circuit",". In particular, the output of the first
receiver","is connected to a first sample and hold subcircuit",". The
output of the second receiver","is connected to a second sample and hold
subcircuit",", while the output of the third receiver","is connected to a
third sample and hold
subcircuit","."]}},{"LVL":"0","ID":"P-00139","PTEXT":{"HIL":[{"BOLD":{"PDAT":"334"}},{"BOLD":{"PDAT":"336"}},{"BOLD":{"PDAT":"338"}},{"BOLD":{"PDAT":"340"}},{"BOLD":{"PDAT":"318"}},{"BOLD":{"PDAT":"320"}},{"BOLD":{"PDAT":"322"}},{"BOLD":{"PDAT":"340"}},{"BOLD":{"PDAT":"342"}},{"BOLD":{"PDAT":"344"}},{"SB":{"PDAT":"3"}},{"BOLD":{"PDAT":"340"}},{"BOLD":{"PDAT":"342"}},{"BOLD":{"PDAT":"344"}},{"BOLD":{"PDAT":"342"}},{"BOLD":{"PDAT":"346"}},{"BOLD":{"PDAT":"342"}},{"SB":{"PDAT":"4"}}],"PDAT":["Each
of the three sample and hold subcircuits",",","and","includes a
switch","receiving an output from the corresponding receiver loop",",",",
or",". The output of the switch","is connected to the positive input
terminal of a buffer amplifier",". One plate of a sample and hold
capacitor","is connected to a node N","between the switch","and the buffer
amplifier",". The other plate of the sample and hold capacitor","is
connected to ground. An output of the buffer amplifier","is connected to a
switch",". The negative input terminal of the buffer amplifier","is
connected to the output of the buffer amplifier at a node
N","."]}},{"LVL":"0","ID":"P-00140","PTEXT":{"HIL":[{"BOLD":{"PDAT":"346"}},{"BOLD":{"PDAT":"334"}},{"BOLD":{"PDAT":"336"}},{"BOLD":{"PDAT":"338"}},{"BOLD":{"PDAT":"348"}},{"BOLD":{"PDAT":"350"}},{"BOLD":{"PDAT":"350"}},{"BOLD":{"PDAT":"332"}},{"BOLD":{"PDAT":"352"}},{"BOLD":{"PDAT":"258"}},{"BOLD":{"PDAT":"204"}}],"PDAT":["The
outputs of the switches","of the three sample and hold
subcircuits",",","and","are connected to a single output line","that is
connected to an input of analog-to-digital (A/D) converter",". The A/D
converter","converts the output of the sample and hold circuit","from an
analog value to a digital value. The digital value is output to a
microprocessor","which processes the digital values from the A/D converter
to determine the relative position between the read head","and the
scale","."]}},{"LVL":"0","ID":"P-00141","PTEXT":{"HIL":[{"BOLD":{"PDAT":"352"}},{"BOLD":{"PDAT":"352"}}],"PDAT":["Each
position within a wavelength can be uniquely identified by the
microprocessor",", according to known techniques and the equations
previously disclosed herein. The microprocessor","also uses known
techniques to keep track of the direction of motion and the number of
wavelengths that are traversed to determine the position for the transducer
relative to an initial reference
position."]}},{"LVL":"0","ID":"P-00142","PTEXT":{"HIL":[{"BOLD":{"PDAT":"352"}},{"BOLD":{"PDAT":"354"}},{"BOLD":{"PDAT":"356"}},{"BOLD":{"PDAT":"356"}},{"BOLD":{"PDAT":"358"}},{"BOLD":{"PDAT":"360"}},{"BOLD":{"PDAT":"362"}},{"BOLD":{"PDAT":"364"}},{"BOLD":{"PDAT":"366"}},{"BOLD":{"PDAT":"368"}},{"BOLD":{"PDAT":"294"}},{"BOLD":{"PDAT":"332"}},{"BOLD":{"PDAT":"356"}},{"BOLD":{"PDAT":"358"}},{"BOLD":{"PDAT":"360"}},{"BOLD":{"PDAT":"324"}},{"BOLD":{"PDAT":"326"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
13"},"PDAT":["The microprocessor","also controls the sequence of signal
sampling by outputting a control signal over a signal line","to a digital
control unit",". The digital control unit","controls the sequence of
transmission, signal sampling and A/D conversion by outputting control
signals on the signal lines",",",",",",",",","and","to the transmitter
drive signal generator","and the sample and hold circuit",". In particular,
as shown in",", the digital control unit","outputs switch control signals
over the signal lines","and","to the first and second switches","and",",
respectively, for controlling the transmitter
excitation."]}},{"LVL":"0","ID":"P-00143","PTEXT":{"HIL":[{"BOLD":{"PDAT":"356"}},{"BOLD":{"PDAT":"362"}},{"BOLD":{"PDAT":"364"}},{"BOLD":{"PDAT":"366"}},{"BOLD":{"PDAT":"368"}},{"BOLD":{"PDAT":"332"}},{"BOLD":{"PDAT":"362"}},{"BOLD":{"PDAT":"340"}},{"BOLD":{"PDAT":"334"}},{"BOLD":{"PDAT":"336"}},{"BOLD":{"PDAT":"338"}},{"BOLD":{"PDAT":"318"}},{"BOLD":{"PDAT":"320"}},{"BOLD":{"PDAT":"322"}},{"BOLD":{"PDAT":"344"}},{"BOLD":{"PDAT":"362"}},{"BOLD":{"PDAT":"340"}},{"BOLD":{"PDAT":"318"}},{"BOLD":{"PDAT":"320"}},{"BOLD":{"PDAT":"322"}},{"BOLD":{"PDAT":"344"}},{"BOLD":{"PDAT":"364"}},{"BOLD":{"PDAT":"366"}},{"BOLD":{"PDAT":"368"}},{"BOLD":{"PDAT":"342"}},{"BOLD":{"PDAT":"334"}},{"BOLD":{"PDAT":"336"}},{"BOLD":{"PDAT":"338"}},{"BOLD":{"PDAT":"350"}},{"BOLD":{"PDAT":"348"}}],"PDAT":["The
digital control unit","outputs switch control signals on the signal
lines",",",",","and","to the sample and hold circuit",". In particular, the
control signal","controllably opens and closes the switches","of the
first-third sample and hold subcircuits",",","and","to connect the receiver
windings",",","and","to the sample and hold capacitors",". When the control
signal","controllably opens the switches",", the signals received from the
receiver windings",",","and","are stored in the sample and hold
capacitors",". The switch control signals on the signal
lines",",","and","are used to controllably connect the outputs of the
buffer amplifiers","of one of the first-third sample and hold
subcircuits",",",", and",", respectively, to the A/D converter","over the
signal
line","."]}},{"LVL":"0","ID":"P-00144","PTEXT":{"HIL":[{"BOLD":{"PDAT":"358"}},{"BOLD":{"PDAT":"360"}},{"BOLD":{"PDAT":"362"}},{"BOLD":{"PDAT":"364"}},{"BOLD":{"PDAT":"366"}},{"BOLD":{"PDAT":"368"}},{"BOLD":{"PDAT":"358"}},{"BOLD":{"PDAT":"324"}},{"BOLD":{"PDAT":"330"}},{"SB":{"PDAT":"DD"}},{"BOLD":{"PDAT":"358"}},{"BOLD":{"PDAT":"324"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
14"},"PDAT":["shows a timing diagram for generating the switch control
signals",",",",",",",",","and","to obtain a position measurement. First,
the switch control signal output on the signal lines","is set to a high
state to close the switch",". This charges up the capacitor","to the supply
voltage V",". The switch control signal on the signal line","is then set to
a low state to open the
switch","."]}},{"LVL":"0","ID":"P-00145","PTEXT":{"HIL":[{"BOLD":{"PDAT":"360"}},{"BOLD":{"PDAT":"326"}},{"BOLD":{"PDAT":"330"}},{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"330"}},{"BOLD":{"PDAT":"290"}},{"SB":{"PDAT":"X"}},{"BOLD":{"PDAT":"14"}}],"PDAT":["Next,
the switch control signal output on the signal line","is changed from a low
state to a high state to close the switch",". This allows the
capacitor","to discharge through the corresponding transmitter winding",".
In particular, the capacitor","forms a resonant circuit with the
transmitter windings","with a chosen resonant frequency on the order of
several MHz. The resonance is a damped oscillation with a waveform
corresponding essentially to the signal S","shown in
FIG.","."]}},{"LVL":"0","ID":"P-00146","PTEXT":{"HIL":[{"SB":{"PDAT":"X"}},{"BOLD":{"PDAT":"318"}},{"BOLD":{"PDAT":"320"}},{"BOLD":{"PDAT":"322"}},{"SB":{"PDAT":"X"}},{"BOLD":{"PDAT":"318"}},{"BOLD":{"PDAT":"320"}},{"BOLD":{"PDAT":"322"}},{"BOLD":{"PDAT":"250"}},{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"9"}}],"PDAT":["The
signal S","appears with the same time function on each of the receiver
windings",",","and",". However, the amplitude and polarity of the signal
S","appearing on each of the receiver windings",",","and","depends on the
position of the read head","relative to the scale",", as shown in
FIG.","."]}},{"LVL":"0","ID":"P-00147","PTEXT":{"HIL":[{"SB":{"PDAT":"X"}},{"BOLD":{"PDAT":"362"}},{"BOLD":{"PDAT":"344"}},{"BOLD":{"PDAT":"332"}},{"SB":{"PDAT":"X"}},{"BOLD":{"PDAT":"362"}},{"BOLD":{"PDAT":"340"}},{"SB":{"PDAT":"X"}},{"BOLD":{"PDAT":"344"}},{"BOLD":{"PDAT":"334"}},{"BOLD":{"PDAT":"336"}},{"BOLD":{"PDAT":"338"}},{"BOLD":{"PDAT":"360"}},{"BOLD":{"PDAT":"326"}}],"PDAT":["Before
the signal S","on the receiver windings reaches a peak, the switch control
signal on the signal line","changes from a low state to a high state to
begin charging each of the sample and hold capacitors","of the sample and
hold circuit",". At a point just after, but approximately at, the peak of
the signal S",", the switch control signal on the signal line","returns to
the low state to open the switches",". This holds the amplitude of the
signals S","for each of the three receiver windings on the corresponding
one of the sample and hold capacitors","of the first-third sample and hold
subcircuits",",","and",". At some point thereafter, the switch control
signal on the signal line","is returned to the low state to open the
switch","."]}},{"LVL":"0","ID":"P-00148","PTEXT":{"HIL":[{"BOLD":{"PDAT":"362"}},{"BOLD":{"PDAT":"364"}},{"BOLD":{"PDAT":"346"}},{"BOLD":{"PDAT":"334"}},{"BOLD":{"PDAT":"344"}},{"BOLD":{"PDAT":"348"}},{"BOLD":{"PDAT":"350"}},{"BOLD":{"PDAT":"350"}},{"BOLD":{"PDAT":"348"}},{"BOLD":{"PDAT":"352"}},{"BOLD":{"PDAT":"364"}},{"BOLD":{"PDAT":"346"}},{"BOLD":{"PDAT":"366"}},{"BOLD":{"PDAT":"368"}},{"BOLD":{"PDAT":"336"}},{"BOLD":{"PDAT":"338"}},{"BOLD":{"PDAT":"350"}},{"BOLD":{"PDAT":"348"}}],"PDAT":["Next,
at some time after the control signal","has returned to the low state, the
switch control signal on the signal line","changes from the low state to
the high state to close the switch","of the sample and hold subcircuit",".
This connects the sampled value held on the corresponding sample and hold
capacitor","over the signal line","to the A/D converter",". The A/D
converter","converts the analog value on the signal line","to a digital
value and outputs the digital value to the microprocessor",". The switch
control signal on the signal line","returns to the low state to open the
corresponding switch",". This sequence is then repeated for the switch
control signals output on the signal lines","and","to connect the signals
sampled by the sample and hold subcircuits","and","to the A/D
converter","over the signal
line","."]}},{"LVL":"0","ID":"P-00149","PTEXT":{"PDAT":"This process is
repeated according to the program in the microprocessor. A program can
easily be made that adapts the sampling rate of the system to the speed of
movement of the transducer, thereby minimizing the current consumption.
This operation is well known to those skilled in the art and thus will not
be described in further detail
herein."}},{"LVL":"0","ID":"P-00150","PTEXT":{"HIL":{"BOLD":{"PDAT":"295"}},"PDAT":["The
previously described signal processing system can be operated on very low
power with the disclosed inductive position transducers, and other related
inductive position transducers, if desired. For example, intermittently
activating the drive signal generator","to support a signal processing
system sampling frequency of about 1 kHz provides sufficient accuracy and
motion tracking capability for most applications. To reduce power
consumption, the drive signal generator duty cycle can be kept low by
making the pulses relatively short. For example, for the 1 kHz sampling
frequency described above, a suitable pulse width is about 0.1-1.0
###mgr;s. That is, the duty cycle of the pulses having sampling period of 1
ms is
0.01%-0.1%."]}},{"LVL":"0","ID":"P-00151","PTEXT":{"HIL":[{"BOLD":{"PDAT":"330"}},{"BOLD":{"PDAT":"290"}},{"BOLD":{"PDAT":"330"}}],"PDAT":["The
resonant frequency of the capacitor","and the winding","is then preferably
selected such that the peak of the voltage across the capacitor","occurs
before the end of the 1.0 ###mgr;s or less pulse. Thus, the resonant
frequency is on the order of several megahertz, as previously disclosed.
The corresponding magnetic flux will therefore be modulated at a frequency
above 1 MHz, and typically of several megahertz. This is considerably
higher than the frequencies of conventional inductive position
transducers."]}},{"LVL":"0","ID":"P-00152","PTEXT":{"HIL":[{"BOLD":{"PDAT":"204"}},{"BOLD":{"PDAT":"274"}},{"BOLD":{"PDAT":"276"}},{"BOLD":{"PDAT":"318"}},{"BOLD":{"PDAT":"320"}},{"BOLD":{"PDAT":"322"}},{"BOLD":{"PDAT":"318"}},{"BOLD":{"PDAT":"320"}},{"BOLD":{"PDAT":"322"}}],"PDAT":["The
inventors have determined that, at these frequencies, the currents
generated in the scale","with the coupling loops","and","produce strong
inductive coupling to the first-third receiver windings",",","and",". The
EMFs generated in the first-third receiver windings",",","and",", and the
resulting output signal, therefore respond strongly to variations in
coupling loop position. This occurs despite the low duty cycle and low
power used by the pulsed drive
signal."]}},{"LVL":"0","ID":"P-00153","PTEXT":{"HIL":{"BOLD":{"PDAT":"294"}},"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
13"},"PDAT":["The strength of the response, combined with the low duty
cycle and low power consumption, allows the inductive position transducer
to make measurements while the drive signal generator","and the remainder
of the signal processing electronic circuit shown in","draw an average
current preferably below 200 ###mgr;A, and more preferably below 75
###mgr;A, for lower power applications. It should be understood that
###ldquo;average current###rdquo; as used herein means the total charge
consumed over one or more measurement cycles, divided by the duration of
the one or more measurement cycles, while the inductive position transducer
is in normal use."]}},{"LVL":"0","ID":"P-00154","PTEXT":{"PDAT":"The
inductive position transducers similar to the type disclosed herein can
therefore be operated with an adequate battery lifetime using three or
fewer commercially available miniature batteries or with a photo-electric
cell. Further details regarding low power signal processing are disclosed
in the incorporated
references."}},{"LVL":"0","ID":"P-00155","PTEXT":{"PDAT":"It should be
appreciated that although the foregoing embodiments are shown with
spatially uniform windings designated as the transmitter windings, and
spatially modulated windings designated as the receiver windings, it will
be apparent to one skilled in the art that the disclosed transducer winding
configurations will retain all of their inventive benefits if the roles of
the transmitter and receiver windings are ###ldquo;reversed###rdquo; in
conjunction with appropriate signal processing. One such appropriate signal
processing technique is disclosed in reference to FIG. 21 of incorporated
U.S. patent application Ser. No. 08/441,769. Other applicable signal
processing techniques will be apparent to those skilled in the
art."}},{"LVL":"0","ID":"P-00156","PTEXT":{"PDAT":"Thus, while this
invention has been described in conjunction with the specific embodiments
outlined above, it is evident that many alternatives, modifications and
variations will be apparent to those skilled in the art. Accordingly, the
preferred embodiments of the invention as set forth above are intended to
be illustrative, not limiting. Various changes may be made without
departing from the spirit and scope of the invention as defined in the
following
claims."}}]}},"BRFSUM":{"BTEXT":{"H":[{"LVL":"1","STEXT":{"PDAT":"BACKGROUND
OF THE INVENTION"}},{"LVL":"1","STEXT":{"PDAT":"SUMMARY OF THE
INVENTION"}}],"PARA":[{"LVL":"0","ID":"P-00002","PTEXT":{"PDAT":"1. Field
of Invention"}},{"LVL":"0","ID":"P-00003","PTEXT":{"PDAT":"This invention
relates to an electronic caliper. More particularly this invention is
directed to electronic calipers using a reduced offset induced current
position transducer."}},{"LVL":"0","ID":"P-00004","PTEXT":{"PDAT":"2.
Description of Related
Art"}},{"LVL":"0","ID":"P-00005","PTEXT":{"PDAT":"U.S. patent application
Ser. No. 08/645,483 filed May 13, 1996, and incorporated herein in its
entirety, discloses an electronic caliper using an inductive position
transducer."}},{"LVL":"0","ID":"P-00006","PTEXT":{"HIL":[{"BOLD":{"PDAT":"2"}},{"BOLD":{"PDAT":"3"}},{"BOLD":{"PDAT":"100"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"106"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"104"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"106"}},{"BOLD":{"PDAT":"106"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"104"}},{"BOLD":{"PDAT":"104"}},{"BOLD":{"PDAT":"102"}}],"FGREF":[{"ID":"DRAWINGS","PDAT":"FIGS.
1"},{"ID":"DRAWINGS","PDAT":"FIG. 1"}],"PDAT":["The operation of the
electronic caliper using the inductive position transducer described in the
application Ser. No. ###apos;483 is generally shown in",",",", and",". As
shown in",", an inductive caliper","includes an elongated beam",". The
elongated beam","is a rigid or semi-rigid bar having a generally
rectangular cross section. A groove","is formed in an upper surface of the
elongated beam",". An elongated measuring scale","is rigidly bonded to the
elongated beam","in the groove",". The groove","is formed in the beam","at
a depth about equal to the thickness of the scale",". Thus, the top surface
of the scale","is very nearly coplanar with the top edges of
beam","."]}},{"LVL":"0","ID":"P-00007","PTEXT":{"HIL":[{"BOLD":{"PDAT":"108"}},{"BOLD":{"PDAT":"110"}},{"BOLD":{"PDAT":"112"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"116"}},{"BOLD":{"PDAT":"118"}},{"BOLD":{"PDAT":"120"}},{"BOLD":{"PDAT":"114"}},{"BOLD":{"PDAT":"108"}},{"BOLD":{"PDAT":"116"}},{"BOLD":{"PDAT":"110"}},{"BOLD":{"PDAT":"118"}},{"BOLD":{"PDAT":"122"}},{"BOLD":{"PDAT":"110"}},{"BOLD":{"PDAT":"118"}}],"PDAT":["A
pair of laterally projecting, fixed jaws","and","are integrally formed near
a first end","of the beam",". A corresponding pair of laterally projecting
movable jaws","and","are formed on a slider assembly",". The outside
dimensions of an object are measured by placing the object between a pair
of engagement surfaces","on the jaws","and",". Similarly, the inside
dimensions of an object are measured by placing the jaws","and","within an
object. The engagement surfaces","of the jaws","and","are positioned to
contact the surfaces on the object to be
measured."]}},{"LVL":"0","ID":"P-00008","PTEXT":{"HIL":[{"BOLD":{"PDAT":"122"}},{"BOLD":{"PDAT":"114"}},{"BOLD":{"PDAT":"114"}},{"BOLD":{"PDAT":"108"}},{"BOLD":{"PDAT":"116"}},{"BOLD":{"PDAT":"122"}},{"BOLD":{"PDAT":"110"}},{"BOLD":{"PDAT":"118"}},{"BOLD":{"PDAT":"100"}}],"PDAT":["The
engagement surfaces","and","are positioned so that when the engagement
surfaces","of the jaws","and","are contacting each other, the engagement
surfaces","of the jaws","and","are aligned with each other. In this
position, the zero position (not shown), both the outside and inside
dimensions measured by the caliper","should be
zero."]}},{"LVL":"0","ID":"P-00009","PTEXT":{"HIL":[{"BOLD":{"PDAT":"100"}},{"BOLD":{"PDAT":"124"}},{"BOLD":{"PDAT":"120"}},{"BOLD":{"PDAT":"124"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"126"}},{"BOLD":{"PDAT":"124"}},{"BOLD":{"PDAT":"126"}},{"BOLD":{"PDAT":"128"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"100"}},{"BOLD":{"PDAT":"128"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"124"}},{"BOLD":{"PDAT":"126"}},{"BOLD":{"PDAT":"100"}}],"PDAT":["The
caliper","also includes a depth bar","which is attached to the slider
assembly",". The depth bar","projects longitudinally from the beam","and
terminates at an engagement end",". The length of the depth bar","is such
that the engagement end","is flush with a second end","of the beam","when
the caliper","is at the zero position. By resting the second end","of the
beam","on a surface in which a hole is formed and extending the depth
bar","into the hole until the end","touches the bottom of the hole, the
caliper","is able to measure the depth of the
hole."]}},{"LVL":"0","ID":"P-00010","PTEXT":{"HIL":[{"BOLD":{"PDAT":"108"}},{"BOLD":{"PDAT":"116"}},{"BOLD":{"PDAT":"110"}},{"BOLD":{"PDAT":"118"}},{"BOLD":{"PDAT":"124"}},{"BOLD":{"PDAT":"134"}},{"BOLD":{"PDAT":"136"}},{"BOLD":{"PDAT":"100"}},{"BOLD":{"PDAT":"130"}},{"BOLD":{"PDAT":"132"}},{"BOLD":{"PDAT":"136"}},{"BOLD":{"PDAT":"130"}},{"BOLD":{"PDAT":"160"}},{"BOLD":{"PDAT":"120"}},{"BOLD":{"PDAT":"132"}},{"BOLD":{"PDAT":"134"}}],"PDAT":["Whether
a measurement is made using the outside measuring jaws","and",", the inside
measuring jaws","and",", or the depth bar",", the measured dimension is
displayed on a conventional digital display",", which is mounted in a
cover","of the caliper",". A pair of push button switches","and","are also
mounted in the cover",". The switch","turns on and off a signal processing
and display electronic circuit","of the slider assembly",". The switch","is
used to reset the display","to
zero."]}},{"LVL":"0","ID":"P-00011","PTEXT":{"HIL":[{"BOLD":{"PDAT":"120"}},{"BOLD":{"PDAT":"138"}},{"BOLD":{"PDAT":"140"}},{"BOLD":{"PDAT":"140"}},{"BOLD":{"PDAT":"146"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"120"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"100"}},{"BOLD":{"PDAT":"144"}},{"BOLD":{"PDAT":"146"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"120"}},{"BOLD":{"PDAT":"102"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
1"},"PDAT":["As shown in",", the slider assembly","includes a base","with a
guiding edge",". The guiding edge","contacts a side edge","of the elongated
beam","when the slider assembly","straddles the elongated beam",". This
ensures accurate operation of the caliper",". A pair of screws","bias a
resilient pressure bar","against a mating edge of the beam","to eliminate
free play between the slider assembly","and the elongated
beam","."]}},{"LVL":"0","ID":"P-00012","PTEXT":{"HIL":[{"BOLD":{"PDAT":"124"}},{"BOLD":{"PDAT":"148"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"148"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"124"}},{"BOLD":{"PDAT":"124"}},{"BOLD":{"PDAT":"148"}},{"BOLD":{"PDAT":"150"}},{"BOLD":{"PDAT":"150"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"128"}},{"BOLD":{"PDAT":"150"}},{"BOLD":{"PDAT":"120"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"128"}}],"PDAT":["The
depth bar","is inserted into a depth bar groove","formed on an underside of
the elongated beam",". The depth bar groove","extends along the underside
of the elongated beam","to provide clearance for the depth bar",". The
depth bar","is held in the depth bar groove","by an end stop",". The end
stop","is attached to the underside of the beam","at the second end",". The
end stop","also prevents the slider assembly","from inadvertently
disengaging from the elongated beam","at the second end","during
operation."]}},{"LVL":"0","ID":"P-00013","PTEXT":{"HIL":[{"BOLD":{"PDAT":"120"}},{"BOLD":{"PDAT":"152"}},{"BOLD":{"PDAT":"138"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"138"}},{"BOLD":{"PDAT":"152"}},{"BOLD":{"PDAT":"152"}},{"BOLD":{"PDAT":"154"}},{"BOLD":{"PDAT":"154"}},{"BOLD":{"PDAT":"158"}},{"BOLD":{"PDAT":"160"}},{"BOLD":{"PDAT":"154"}},{"BOLD":{"PDAT":"156"}},{"BOLD":{"PDAT":"136"}},{"BOLD":{"PDAT":"154"}},{"BOLD":{"PDAT":"160"}}],"PDAT":["The
slider assembly","also includes a read head assembly","mounted on the
base","above the elongated beam",". Thus, the base","and read head
assembly","move as a unit. The read head assembly","includes a
substrate","such as a conventional printed circuit board. The
substrate","bears an inductive read head","on its lower surface. A signal
processing and display electronic circuit","is mounted on an upper surface
of the substrate",". A resilient seal","is compressed between the
cover","and the substrate","to prevent contamination of the signal
processing and display electronic
circuit","."]}},{"LVL":"0","ID":"P-00014","PTEXT":{"HIL":[{"BOLD":{"PDAT":"158"}},{"BOLD":{"PDAT":"162"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
2"},"PDAT":["As shown in",", the read head","is covered by a thin, durable,
insulative coating",", which is preferably approximately 50 microns
thick."]}},{"LVL":"0","ID":"P-00015","PTEXT":{"HIL":[{"BOLD":{"PDAT":"104"}},{"BOLD":{"PDAT":"164"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"164"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"168"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"168"}},{"BOLD":{"PDAT":"1"}}],"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
1"},{"ID":"DRAWINGS","PDAT":"FIG. 2"}],"PDAT":["The scale","is preferably
an elongated printed circuit board (PCB)",". As shown in",", a set of
magnetic flux modulators","are spaced apart along the PCB","in a periodic
pattern. The flux modulators","are preferably formed of copper. The flux
modulators","are preferably formed according to conventional printed
circuit board manufacturing techniques, although many other methods of
fabrication may be used. As shown in",", a protective insulating
layer","(preferably being at most 100 microns thick) covers the flux
modulators",". The protective layer","can include printed markings, as
shown in
FIG.","."]}},{"LVL":"0","ID":"P-00016","PTEXT":{"HIL":[{"BOLD":{"PDAT":"120"}},{"BOLD":{"PDAT":"158"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"170"}},{"BOLD":{"PDAT":"162"}},{"BOLD":{"PDAT":"168"}},{"BOLD":{"PDAT":"170"}},{"BOLD":{"PDAT":"158"}},{"BOLD":{"PDAT":"166"}}],"PDAT":["The
slider assembly","carries the read head","so that it is slightly separated
from the beam","by an air gap","formed between the insulative
coatings","and",". The air gap","is preferably on the order of 0.5 mm.
Together, the read head","and the flux modulators","form an inductive
transducer."]}},{"LVL":"0","ID":"P-00017","PTEXT":{"HIL":[{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"174"}},{"BOLD":{"PDAT":"102"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"174"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"174"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
3"},"PDAT":["As shown in",", the magnetic flux modulators","are distributed
along a measuring axis","of the elongated beam","at a pitch equal to a
wavelength ###lgr;, which is described in more detail below. The flux
modulators","have a nominal width along the measuring axis","of ###lgr;/2.
The flux modulators","have a width d in a direction perpendicular to the
measuring
axis","."]}},{"LVL":"0","ID":"P-00018","PTEXT":{"HIL":[{"BOLD":{"PDAT":"158"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"178"}},{"BOLD":{"PDAT":"178"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"176"}}],"PDAT":["The
read head","includes a generally square transmitter winding","that is
connected to a drive signal generator",". The drive signal
generator","provides a time varying drive signal to the transmitter
winding",". The time varying drive signal preferably results in a
sinusoidal signal in the transmitter winding",", and more preferably an
exponentially decaying sinusoidal signal. When the time varying drive
signal is applied to the transmitter winding",", the time varying current
flowing in the transmitter winding","generates a time varying, or changing,
magnetic field. Because the transmitter winding","is generally
rectangularly shaped, the generated magnetic field is generally constant
within a flux region inside the transmitter
winding","."]}},{"LVL":"0","ID":"P-00019","PTEXT":{"HIL":[{"BOLD":{"PDAT":"158"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"158"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"184"}},{"BOLD":{"PDAT":"186"}},{"BOLD":{"PDAT":"184"}},{"BOLD":{"PDAT":"154"}},{"BOLD":{"PDAT":"186"}},{"BOLD":{"PDAT":"154"}},{"BOLD":{"PDAT":"154"}},{"BOLD":{"PDAT":"184"}},{"BOLD":{"PDAT":"186"}},{"BOLD":{"PDAT":"184"}},{"BOLD":{"PDAT":"186"}},{"BOLD":{"PDAT":"188"}},{"BOLD":{"PDAT":"154"}}],"PDAT":["The
read head","further includes a first receiver winding","and a second
receiver winding","positioned on the read head","within the flux region
inside the transmitter winding",". Each of the first receiver winding","and
the second receiver winding","is formed by a plurality of first loop
segments","and second loop segments",". The first loop segments","are
formed on a first surface of a layer of the printed circuit board",". The
second loop segments","are formed on another surface of the layer of the
printed circuit board",". The layer of the printed circuit board","acts as
an electrical insulation layer between the first loop segments","and the
second loop segments",". Each end of the first loop segments","is connected
to one end of one of the second loop segments","through
feed-throughs","formed in the layer of the printed circuit
board","."]}},{"LVL":"0","ID":"P-00020","PTEXT":{"HIL":[{"BOLD":{"PDAT":"184"}},{"BOLD":{"PDAT":"186"}},{"BOLD":{"PDAT":"184"}},{"BOLD":{"PDAT":"186"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
3"},"PDAT":["The first and second loop segments","and","are preferably
sinusoidally shaped. Accordingly, as shown in","the first and second loop
segments","and","forming each of the receiver windings","and","form a
sinusoidally shaped periodic pattern having a wavelength ###lgr;. Each of
the receiver windings","and","are thus formed having a plurality of
loops","and","."]}},{"LVL":"0","ID":"P-00021","PTEXT":{"HIL":[{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"174"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"184"}},{"BOLD":{"PDAT":"186"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"174"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}}],"PDAT":["The
loops","and","in each of the first and second receiver
windings","and","have a width along the measuring axis","equal to
###lgr;/2. Thus, each pair of adjacent loops","and","has a width equal to
###lgr;. Furthermore, the first and second loop segments","and","go through
a full sinusoidal cycle in each pair of adjacent loops","and",". Thus,
###lgr; corresponds to the sinusoidal wavelength of the first and second
receiver windings","and",". Furthermore, the second receiver winding","is
offset by ###lgr;/4 from the first receiver winding","along the measuring
axis",". That is, the first and second receiver windings","and","are in
quadrature."]}},{"LVL":"0","ID":"P-00022","PTEXT":{"HIL":[{"BOLD":{"PDAT":"178"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"176"}},{"ITALIC":{"PDAT":"a,"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"176"}},{"ITALIC":{"PDAT":"b"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}}],"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
3"},{"ID":"DRAWINGS","PDAT":"FIG. 3"}],"PDAT":["The changing drive signal
from the drive signal generator","is applied to the transmitter
winding","such that current flows in a transmitter winding","from a first
terminal","through the transmitter winding","and out through a second
terminal",". Thus, the magnetic field generated by the transmitter
winding","descends into the plane of","within the transmitter winding","and
rises up out of the plane of","outside the transmitter winding",".
Accordingly, the changing magnetic field within the transmitter
winding","generates an induced electromagnetic force (EMF) in each of the
loops","and","formed in the receiver
windings","and","."]}},{"LVL":"0","ID":"P-00023","PTEXT":{"HIL":[{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}}],"PDAT":["The
loops","and","have opposite winding directions. Thus, the EMF induced in
the loops","has a polarity that is opposite to the polarity of the EMF
induced in the loops",". The loops","and","enclose the same area and thus
nominally the same amount of magnetic flux. Therefore, the absolute
magnitude of the EMF generated in each of the loops","and","is nominally
the
same."]}},{"LVL":"0","ID":"P-00024","PTEXT":{"HIL":[{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}}],"PDAT":["There
are preferably equal numbers of loops","and","in each of the first and
second receiver windings","and",". Thus, the positive polarity EMF induced
in the loops","is exactly offset by the negative polarity EMF induced in
the loops",". Accordingly, the net nominal EMF on each of the first and
second receiver windings","and","is zero. Thus, no signal should be output
from the first and second receiver windings","and","as a result solely of
the direct coupling from the transmitter winding","to the receiver
windings","and","."]}},{"LVL":"0","ID":"P-00025","PTEXT":{"HIL":[{"BOLD":{"PDAT":"158"}},{"BOLD":{"PDAT":"164"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"166"}}],"PDAT":["When
the read head","is placed in proximity to the PCB",", the changing magnetic
flux generated by the transmitter winding","also passes through the flux
modulators",". The flux modulators","modulate the changing magnetic flux
and can be either flux enhancers or flux
disrupters."]}},{"LVL":"0","ID":"P-00026","PTEXT":{"HIL":[{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"164"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"166"}}],"PDAT":["When
the flux modulators","are provided as flux disrupters, the flux
modulators","are formed as conductive plates or thin conductive films on
the PCB",". As the changing magnetic flux passes through the conductive
plates or thin films, eddy currents are generated in the conductive plates
or thin films. These eddy currents in turn generate magnetic fields having
a field direction that is opposite to that of the magnetic field generated
by the transmitter winding",". Thus, in areas proximate to each of the flux
disrupter-type flux modulators",", the net magnetic flux is less than the
net magnetic flux in areas distant from the flux disrupter type flux
modulators","."]}},{"LVL":"0","ID":"P-00027","PTEXT":{"HIL":[{"BOLD":{"PDAT":"164"}},{"BOLD":{"PDAT":"158"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"180"}},{"ITALIC":{"PDAT":"a"}},{"BOLD":{"PDAT":"180"}},{"ITALIC":{"PDAT":"b."}}],"PDAT":["When
the scale PCB","is positioned relative to the read head","such that the
flux disrupters","are aligned with the positive polarity loops","of the
receiver winding",", the net EMF generated in the positive polarity
loops","is reduced compared to the net EMF generated in the negative
polarity loops",". Thus, the receiver winding","becomes unbalanced and has
a net negative signal across its output
terminals","and"]}},{"LVL":"0","ID":"P-00028","PTEXT":{"HIL":[{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"180"}},{"ITALIC":{"PDAT":"a"}},{"BOLD":{"PDAT":"180"}},{"ITALIC":{"PDAT":"b."}}],"PDAT":["Similarly,
when the flux disrupters","are aligned with the negative polarity loops",",
the net magnetic flux through the negative polarity loops","is disrupted or
reduced. Thus, the net EMF generated in the negative polarity loops","is
reduced relative to the net EMF generated in the positive polarity
loops",". Thus, the first receiver winding","has a net positive signal
across its output
terminals","and"]}},{"LVL":"0","ID":"P-00029","PTEXT":{"HIL":[{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"104"}},{"BOLD":{"PDAT":"164"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"166"}}],"PDAT":["When
the flux modulators","are provided as flux enhancers, this result is
exactly reversed. The flux enhancer type flux modulators","are formed by
portions of high magnetic permeability material provided in or on the scale
member",", in place of the conductive plates of PCB",". The magnetic flux
generated by the transmitter winding","preferentially passes through the
high magnetic permeability flux enhancer type flux modulators",". That is,
the density of the magnetic flux within the flux enhancers","is enhanced,
while the flux density in areas outside the flux enhancers","is
reduced."]}},{"LVL":"0","ID":"P-00030","PTEXT":{"HIL":[{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"182"}},{"ITALIC":{"PDAT":"a"}},{"BOLD":{"PDAT":"182"}},{"ITALIC":{"PDAT":"b"}},{"BOLD":{"PDAT":"182"}}],"PDAT":["Thus,
when the flux enhancers","are aligned with the positive polarity loops","of
the second receiver winding",", the flux density through the positive
polarity loops","is greater than a flux density passing through the
negative polarity loops",". Thus, the net EMF generated in the positive
polarity","increases, while the net EMF induced in the negative polarity
loops","decreases. This appears as a positive signal across the
terminals","and","of the second receiver
winding","."]}},{"LVL":"0","ID":"P-00031","PTEXT":{"HIL":[{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"182"}},{"ITALIC":{"PDAT":"a"}},{"BOLD":{"PDAT":"182"}},{"ITALIC":{"PDAT":"b"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"104"}}],"PDAT":["When
the flux enhancers","are aligned with the negative polarity loops",", the
negative polarity loops","generate an enhanced EMF relative to the EMF
induced in the positive polarity loops",". Thus, a negative signal appears
across the terminals","and","of the second receiver winding",". It should
also be appreciated that, as outlined in the incorporated reference, both
the flux enhancing and flux disrupting effects can be combined in a single
scale, where the flux enhancers and flux disrupters are interleaved along
the length of the scale",". This would act to enhance the modulation of the
induced EMF, because the effects of both types of flux modulators
additively
combine."]}},{"LVL":"0","ID":"P-00032","PTEXT":{"HIL":[{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}}],"PDAT":["As
indicated above, the width and height of the flux modulators","are
nominally ###lgr;/2 and d, respectively, while the pitch of the flux
modulators","is nominally ###lgr;. Similarly, the wavelength of the
periodic pattern formed in the first and second receiver
windings","and","is nominally ###lgr; and the height of the
loops","and","is nominally d. Furthermore, each of the
loops","and","enclose a nominally constant
area."]}},{"LVL":"0","ID":"P-00033","PTEXT":{"HIL":[{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"192"}}],"FGREF":{"ID":"DRAWINGS","PDAT":"FIG.
4A"},"PDAT":["shows the position-dependent output from the positive
polarity loops","as the flux modulators","move relative to the positive
polarity loops",". Assuming the flux modulators","are flux disrupters, the
minimum signal amplitude corresponds to those positions where the flux
disrupters","exactly align with the positive polarity loops",", while the
maximum amplitude positions correspond to the flux disrupters","being
aligned with the negative polarity
loops","."]}},{"LVL":"0","ID":"P-00034","PTEXT":{"HIL":[{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"190"}}],"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
4B"},{"ID":"DRAWINGS","PDAT":"FIG. 4A"},{"ID":"DRAWINGS","PDAT":"FIGS. 4A
and 4B"}],"PDAT":["shows the signal output from each of the negative
polarity loops",". As with the signal shown in",", the minimum signal
amplitude corresponds to those positions where the flux
disrupters","exactly align with the positive polarity loops",", while the
maximum signal output corresponds to those positions where the flux
disrupters exactly align with the negative polarity loops",". It should be
appreciated that if flux enhancers were used in place of flux disrupters,
the minimum signal amplitudes in","would correspond to the flux
enhancers","aligning with the negative polarity loops",", while the maximum
signal amplitude would correspond to the flux enhancers","aligning with the
positive polarity
loops","."]}},{"LVL":"0","ID":"P-00035","PTEXT":{"HIL":[{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}}],"FGREF":[{"ID":"DRAWINGS","PDAT":"FIG.
4C"},{"ID":"DRAWINGS","PDAT":"FIGS. 4A and
4B"},{"ID":"DRAWINGS","PDAT":"FIG. 4C"}],"PDAT":["shows the net signal
output from either of the first and second receiver windings","and",". This
net signal is equal to the sum of the signals output from the positive and
negative polarity loops","and",", i.e., the sum of the signal shown in",".
The net signal shown in","should ideally be symmetrical around zero, that
is, the positive and negative polarity loops","and","should be exactly
balanced to produce a symmetrical output with zero
offset."]}},{"LVL":"0","ID":"P-00036","PTEXT":{"HIL":[{"SB":{"PDAT":"o"}},{"SB":{"PDAT":"o"}}],"PDAT":["However,
a ###ldquo;DC###rdquo; (position independent) component often appears in
the net signal in a real device. This DC component is the offset signal
V",". This offset V","is an extraneous signal component that complicates
signal processing and leads to undesirable position measurement errors.
This offset has two
sources."]}},{"LVL":"0","ID":"P-00037","PTEXT":{"HIL":[{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"166"}}],"PDAT":["First,
the full amplitude of the transmitter field passes through the first and
second receiver windings","and",". As outlined above, this induces a
voltage in each loop","and",". The induced voltage nominally cancels
because the loops","and","have opposite winding directions. However, to
perfectly cancel the induced voltage in the receiver windings requires the
positive and negative loops","and","to be precisely positioned and shaped,
for a perfectly balanced result. The tolerances on the balance are critical
because the voltages induced directly into the receiver winding
loops","and","by the transmitter winding","are much stronger than the
modulation in the induced voltage caused by the flux
modulators","."]}},{"LVL":"0","ID":"P-00038","PTEXT":{"HIL":[{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"176"}}],"PDAT":["Second,
the spatially modulated field created by the flux modulators also exhibits
an average position-independent offset component. That is, the flux
modulators","within the magnetic field generated by the transmitter
winding","all create the same polarity spatial modulation in the magnetic
field. For example, when flux disrupters are used, the induced eddy current
field from the flux modulators has an offset because the flux disrupters
within the transmitter field all create a same polarity secondary magnetic
field. At the same time, the space between the flux disrupters does not
create a secondary magnetic
field."]}},{"LVL":"0","ID":"P-00039","PTEXT":{"HIL":[{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"176"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}}],"PDAT":["Thus,
each positive polarity loop","and each negative polarity loop","of the
receiver windings","and","sees a net magnetic field that varies between a
minimum value and a maximum value having the same polarity. The mean value
of this function is not balanced around zero, i.e., it has a large nominal
offset. Similarly, when flux enhancers are used, the field modulation due
to the flux enhancers has an offset because the enhancers within the
transmitter winding","all create the same field modulation, while the space
between the modulators provides no modulation. Each positive and negative
polarity loop","and","of each receiver winding","or","therefore sees a
modulated field that varies between a minimum value and a maximum value
having the same polarity. The mean value of this function also has a large
nominal
offset."]}},{"LVL":"0","ID":"P-00040","PTEXT":{"HIL":[{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}}],"PDAT":["A
receiver winding having an equal number of similar positive and negative
polarity loops","and","helps eliminate the offset components. However, any
imperfection in the balance between the positive and negative polarity
loops","and","allows residual offsets according to the previous
description."]}},{"LVL":"0","ID":"P-00041","PTEXT":{"HIL":[{"BOLD":{"PDAT":"190"}},{"BOLD":{"PDAT":"192"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}}],"PDAT":["Both
these offset components are expected to be canceled solely by the symmetry
between the positive and negative polarity loops","and","in the first and
second windings","and",". This puts very stringent requirements on the
manufacturing precision of the receiver windings","and",". Experience in
manufacturing a transducer indicates it is practically impossible to
eliminate this source of error from the induced current position transducer
of a conventional
caliper."]}},{"LVL":"0","ID":"P-00042","PTEXT":{"HIL":[{"BOLD":{"PDAT":"166"}},{"BOLD":{"PDAT":"180"}},{"BOLD":{"PDAT":"182"}},{"BOLD":{"PDAT":"164"}},{"BOLD":{"PDAT":"158"}}],"PDAT":["Furthermore,
any deviations in the width or pitch of the flux modulators","will
unbalance the receiver windings","or","in a way that is independent of the
relative position between the PCB","and the read
head","."]}},{"LVL":"0","ID":"P-00043","PTEXT":{"PDAT":"Any signal
component which is independent of the transducer position, such as the
aforementioned offset components, is regarded as an extraneous signal to
the operation of the transducer. Such extraneous signals complicate the
required signal processing circuitry and otherwise lead to errors which
compromise the accuracy of the
transducer."}},{"LVL":"0","ID":"P-00044","PTEXT":{"PDAT":"One proposed
solution attempts to reduce the extraneous coupling between the transmitter
and receiver windings simply by placing the receiver winding distant from
the field produced by the transmitter winding. However, the effectiveness
of this technique alone depends on the degree of separation between the
transmitter and receiver windings. Hence, this technique contradicts the
need for high accuracy linear caliper of compact size. Alternatively, the
transmitter field can be confined with magnetically permeable materials so
that the effectiveness of a given degree of separation is increased.
However, this technique leads to additional complexity, cost, and
sensitivity to external fields, in a practical
device."}},{"LVL":"0","ID":"P-00045","PTEXT":{"PDAT":"Furthermore, the
simple winding configurations disclosed in association with these
techniques include no means for creating a device with a measuring range
significantly exceeding the span of the transmitter and receive windings.
In addition, the simple winding configurations provide no means for
significantly enhancing the degree of output signal change per unit of
displacement for a given measuring range. Thus, the practical measuring
resolution of these devices is limited for a given measuring
range."}},{"LVL":"0","ID":"P-00046","PTEXT":{"PDAT":"The need for a high
accuracy inductive linear caliper which rejects both extraneous signal
components and external fields, is compact, of simple construction, and
capable of high resolution measurement over an extended measuring range
without requiring increased fabrication and circuit accuracies, has
therefore not been met
previously."}},{"LVL":"0","ID":"P-00047","PTEXT":{"PDAT":"This invention
provides an electronic caliper using an induced current position transducer
with improved winding configurations. The improved winding configurations
increase the proportion of the useful output signal component relative to
extraneous (###ldquo;offset###rdquo components of the output signal
without requiring increased transducer fabrication accuracy. Furthermore,
the winding configurations provide means to enhance the degree of output
signal change per unit of displacement for a given measuring
range."}},{"LVL":"0","ID":"P-00048","PTEXT":{"PDAT":"This is accomplished
by winding configurations that minimize and nullify the direct coupling
between the transmitter and receiver windings while providing enhanced
position-dependent coupling between them through a plurality of coupling
windings on the scale which interact with a plurality of spatial
modulations of the
windings."}},{"LVL":"0","ID":"P-00049","PTEXT":{"PDAT":"In particular, this
invention includes an electronic caliper using a reduced offset induced
current position transducer having a scale and a read head that are movable
relative to each other along a measuring axis. The read head includes a
pair of receiver windings extending along the measuring axis and positioned
in a center portion of the read head. The read head further includes a
transmitter winding extending along the measuring axis and positioned
laterally from the receiver windings in a direction perpendicular to the
measuring axis."}},{"LVL":"0","ID":"P-00050","PTEXT":{"PDAT":"In a first
embodiment of the electronic caliper using the induced current position
transducer of this invention, the transmitter winding is divided into a
first transmitter loop and a second transmitter loop, with the first
transmitter loop placed on one side of the receiver windings and the second
transmitter loop placed on the other side of the receiver windings. The
magnetic fields created by the first and second loops of the transmitter
winding counteract each other in the area of the receiver winding. This
minimizes the extraneous effects of any direct coupling from the
transmitter winding to the receiver
winding."}},{"LVL":"0","ID":"P-00051","PTEXT":{"PDAT":"The scale member has
a plurality of first coupling loops extending along the measuring axis and
interleaved with a plurality of second measuring loops also extending along
the measuring axis. The first coupling loops have a first portion aligned
with the first transmitter winding and a second portion aligned with the
receiver windings. Similarly, the second coupling loops have a first
portion aligned with the second transmitter winding and a second portion
aligned with the receiver
windings."}},{"LVL":"0","ID":"P-00052","PTEXT":{"PDAT":"In a second
embodiment of the induced current position transducer of this invention,
the transmitter has only one loop, which is placed alongside the receiver
windings on the read head. The scale member in this case has a plurality of
first coupling loops arrayed along the measuring axis and interleaved with
a second plurality of coupling loops also arrayed along the measuring axis.
Both the first and second coupling loops have a first portion aligned with
the transmitter winding and a second portion aligned with the receiver
windings."}},{"LVL":"0","ID":"P-00053","PTEXT":{"PDAT":"The first and
second portions of each first coupling loop are connected in series and are
###ldquo;untwisted###rdquo;. Thus, the magnetic fields induced in the first
and second portions of the first coupling loops have the same polarity. In
contrast, the first and second portion of each second coupling loop are
connected in series and are ###ldquo;twisted###rdquo;. In this case, the
magnetic fields induced in the first and second portions of the second
coupling loops have opposite polarities. This creates an alternating
induced magnetic field along the measuring axis in the area under the
receiver winding in response to exciting the transmitter
winding."}},{"LVL":"0","ID":"P-00054","PTEXT":{"PDAT":"These winding
configurations substantially eliminate several extraneous signal
components, resulting in simplified signal processing and improved
transducer accuracy and robustness in an economical
design."}},{"LVL":"0","ID":"P-00055","PTEXT":{"PDAT":"This invention
provides an improved electronic caliper that uses an induced current
position transducer with improved winding configurations. This invention
uses a transducer with example embodiments that are described in copending
U.S. patent application Ser. No. 08/834,432, filed on Apr. 16, 1997,
entitled ###ldquo;REDUCED OFFSET HIGH ACCURACY INDUCED CURRENT POSITION
TRANSDUCER###rdquo; which is hereby incorporated by reference in its
entirety."}},{"LVL":"0","ID":"P-00056","PTEXT":{"PDAT":"These and other
features and advantages of this invention are described in or are apparent
from the following detailed description of the preferred
embodiments."}}]}}}}}}
On Wednesday, September 17, 2014 6:18:00 PM UTC+5:30, David Pilato wrote:
You can't. If test2 is a string for the first doc, it can not be an object
for the second doc.
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components of the output signal