Analog to digital converter having an electrostatic encoder

Claim 2

In an analog-to-digital converter for providing a set of output signals coded to represent the angular position of a shaft, signal generating means for providing signals of first and second phases, encoder means including a code member having a plurality of discrete arcuate sense elements disposed on a surface thereof in a single annular track, each of said sense elements having the same arcuate lengths, and energizing means including an energizing member rotatable with said shaft relative to said code member including stimulus means having first and second stimulus elements disposed in a predetermined pattern on a surface of said energizing member which is adjacent said sense elements such that said first and second stimulus elements overlie different sets of said sense elements for each angular position of said shaft to be represented to selectively couple signals of said first phase to certain of said sense elements and signals of said second phase to certain others of said sense elements as a function of the angular position of said shaft, said first and second stimulus elements each having a first arcuate segment of a length which is approximately three and onehalf times the arcuate length of a sense element and a second arcuate segment of a length which is approximately one and onehalf times the arcuate length of a sense element whereby the signals coupled to said sense elements provide a different pattern of signals of said first and second phases over said sense elements for each 18* of rotation of said shaft.

Claim 3

In an analog-to-digital converter for providing a set of output signals coded to represent the angular position of a shaft, signal generating means for providing signals of first and second phases, encoder means including a code member having a plurality of discrete arcuate sense elements disposed on a surface thereof in a single annular track, each of said sense elements having the same arcuate lengths, and energizing means including an energizing member rotatable with said shaft relative to said code member including stimulus means having first and second stimulus elements disposed in a predetermined pattern on a surface of said energizing member which is adjacent said sense elements such that said first and second stimulus elements overlie different sets of said sense elements for each angular position of said shaft to be represented to selectively couple signals of said first phase to certain of said sense elements and signals of said second phase to certain others of said sense elements as a function of the angular position of said shaft, said first and second stimulus elements each having a first arcuate segment of a length which is approximately three and one-half times the arcuate length of a sense element and a second arcuate segment of a length which is approximately one and one-half times the arcuate length of a sense element whereby the signals coupled to said sense elements provide a different pattern of signals of said first and second phases over said sense elements for each 18* of rotation of said shaft.

Claim 4

In an analog-to-digital converter for providing a set of output signals coded to represent the angular position of a shaft, signal generating means for providing signals of first and second phases, encoder means including a code member having a plurality of discrete arcuate sense elements disposed on a surface thereof in a single annular track, each of said sense elements having the same arcuate lengths, and energizing means including an energizing member rotatable with said shaft relative to said code member including stimulus means having first and second stimulus elements disposed in a predetermined pattern on a surface of said energizing member which is adjacent said sense elements such that said first and second stimulus elements overlie different sets of said sense elements for each angular position of said shaft to be represented to selectively couple signals of said first phase to certain of said sense elements and signals of said second phase to certain others of said sense elements as a function of the angular position of said shaft, said first and second stimulus elements each having a first arcuate segment of a length which is approximately three and one-half times the arcuate length of a sense element and a second arcuate segment of a length which is approximately one and one-half times the arcuate length of a sense element whereby the signals coupled to said sense elements provide a different pattern of signals of said first and second phases over said sense elements for each 18* of rotation of said shaft.

Claim 5

An analog-to-digital converter as set forth in claim 1 in which said encoder means further includes means foR providing signals of said first phase for coupling to said first stimulus element and means for providing signals of said second phase for coupling to said second stimulus element, whereby signals of said first phase are coupled to ones of the sense elements which the first stimulus element means overlies and signals of said second phase are coupled to the ones of the sense elements which the second stimulus element means overlies.

Claim 6

In an analog-to-digital converter for providing a set of output signals coded to represent the angular position of a shaft, signal generating means for providing signals of first and second phases, encoder means including a code member having a plurality of sense elements and an energizing member rotatable with said shaft relative to said code member including stimulus means for selectively coupling signals of said first phase to certain ones of said sense elements and signals of said second phase to certain other ones of said sense elements as a function of the angular position of said shaft to provide different patterns of signals for different positions to the shaft, and detecting means including input circuit means having a plurality of input circuits each connected to a different one of said sense elements, each of said input circuits being operable when enabled to provide a control signal of the same phase as the signal being coupled to an associated sense element, enable means for enabling said input circuits one at a time, and phase detecting means including reference means for providing a reference signal of one of said phases and phase comparison means including a flip flop having a set input connected to an output of said input circuit means and a clock input connected to an output of said reference means for comparing each of said control signals with said reference signal, said phase comparison means being operable to provide a first output signal whenever the phases of the compared signals are the same and a second output signal whenever the phases of the compared signals are different.

Claim 7

In an analog-to-digital converter for providing a set of output signals coded to represent the angular position of a shaft, signal generating means for providing signals of first and second phases, encoder means including a code member having a plurality of sense elements and an energizing member rotatable with said shaft relative to said code member including stimulus means for selectively coupling signals of said first phase to certain ones of said sense elements and signals of said second phase to certain other ones of said sense elements as a function of the angular position of said shaft to provide different patterns of signals for different positions to the shaft, and detecting means including input circuit means having a plurality of input circuits each connected to a different one of said sense elements, each of said input circuits being operable when enabled to provide a control signal of the same phase as the signal being coupled to an associated sense element, enable means for enabling said input circuits one at a time, and phase detecting means including reference means for providing a reference signal of one of said phases and phase comparison means including a flip flop having a set input connected to an output of said input circuit means and a clock input connected to an output of said reference means for comparing each of said control signals with said reference signal, said phase comparison means being operable to provide a first output signal whenever the phases of the compared signals are the same and a second output signal whenever the phases of the compared signals are different.

Claim 8

An analog-to-digital converter as set forth in claim 3 in which said phase comparison means further includes means connected between the output of said input circuit means and the set input of said flip flop for delaying each control signal relative to said reference signal.

Claim 9

In an analog-to-digital converter for providing a set of output signals coded to represent the angular position of a shaft, signal generating means for providing signals of first and second phases, encoder means including a code member having a plurality of sense elements disposed on said code member, and an energizing member mounted for rotation by said shaft and having stimulus means disposed on a surface thereof which is adjacent said sense elements for selectively coupling signals of said first phase to certain ones of said sense elements and signals of said second phase to certain other ones of said sense elements as a function of the angular position of said shaft, signal detecting means including a plurality of signal detecting circuits, each signal detecting circuit having an input individually connected to a different one of said sense elements, each of said signal detecting circuits being responsive to signals coupled to an associated sense element to provide an output signal representing the phase thereof , and phase detecting means including reference means for providing a reference signal of one of said phases, and a phase comparison flip flop having a first input connected to an output of said signal detecting means and a second input connected to an output of said reference means for comparing each output signal provided by said signal detecting means with said reference signal to provide a first binary output signal whenever the phases of the compared signals are the same and a second binary output signal whenever the phases of the compared signals are different to thereby generate a correspondingly different logic word for each pattern of signaLs extended to said signal detecting means.

Claim 10

In an analog-to-digital converter for providing a set of output signals coded to represent the angular position of a shaft, signal generating means for providing signals of first and second phases, encoder means including a code member having a plurality of sense elements disposed on said code member, and an energizing member mounted for rotation by said shaft and having stimulus means disposed on a surface thereof which is adjacent said sense elements for selectively coupling signals of said first phase to certain ones of said sense elements and signals of said second phase to certain other ones of said sense elements as a function of the angular position of said shaft, signal detecting means including a plurality of signal detecting circuits, each signal detecting circuit having an input individually connected to a different one of said sense elements, each of said signal detecting circuits being responsive to signals coupled to an associated sense element to provide an output signal representing the phase thereof , and phase detecting means including reference means for providing a reference signal of one of said phases, and a phase comparison flip flop having a first input connected to an output of said signal detecting means and a second input connected to an output of said reference means for comparing each output signal provided by said signal detecting means with said reference signal to provide a first binary output signal whenever the phases of the compared signals are the same and a second binary output signal whenever the phases of the compared signals are different to thereby generate a correspondingly different logic word for each pattern of signaLs extended to said signal detecting means.

Claim 11

An analog-to-digital converter as set forth in claim 5 in which said stimulus means comprises first and second stimulus elements of predetermined configurations whereby said first stimulus elements overlie said certain ones of said sense elements while said second stimulus elements overlie said certain other sense elements.

Claim 12

In an analog-to-digital converter for providing a set of binary output signals coded to represent the angular position of a shaft, signal generating means for providing signals of first and second phases, encoder means including a code member having a plurality of sense elements disposed in a single angular track, and an energizing member mounted for rotation by said shaft , said energizing member having first and second stimulus elements disposed on the surface thereof which is adjacent said sense elements, and first and second signal elements disposed on a further surface and connected to said first and second stimulus elements, respectfully, and input means including an input member having first and second input elements connected to outputs of said signal generating means for coupling signals of said first and second phases to said first and second signal elements, respectively, said first and second stimulus elements being disposed on said surface in a pattern in which said first stimulus element overlies certain ones of said sense elements while the second stimulus element overlies certain others of said sense elements to selectively couple signals of said first phase to said certain ones of said sense elements and signals of said second phase to said certain others of said sense elements as a function of the angular position of said shaft, and signal detecting means including a plurality of input circuits each connected to a different one of said sense elements, circuit select means for enabling said input circuits one at a time to provide a control signal of the same phase as the signal being coupled to the associated sense element, and phase detecting circuit means for providing in sequence a first binary output signal for each control signal of said first phase provided by said signal detecting means and a second binary output signal for each control signal of said second phase provided by said signal detecting means as said input circuits are enabled whereby the set of outputs provided by said phase detecting circuit means represents the angular position of said shaft.

Claim 13

In an analog-to-digital converter for providing a set of binary output signals coded to represent the angular position of a shaft, signal generating means for providing signals of first and second phases, encoder means including a code member having a plurality of sense elements disposed in a single angular track, and an energizing member mounted for rotation by said shaft , said energizing member having first and second stimulus elements disposed on the surface thereof which is adjacent said sense elements, and first and second signal elements disposed on a further surface and connected to said first and second stimulus elements, respectfully, and input means including an input member having first and second input elements connected to outputs of said signal generating means for coupling signals of said first and second phases to said first and second signal elements, respectively, said first and second stimulus elements being disposed on said surface in a pattern in which said first stimulus element overlies certain ones of said sense elements while the second stimulus element overlies certain others of said sense elements to selectively couple signals of said first phase to said certain ones of said sense elements and signals of said second phase to said certain others of said sense elements as a function of the angular position of said shaft, and signal detecting means including a plurality of input circuits each connected to a different one of said sense elements, circuit select means for enabling said input circuits one at a time to provide a control signal of the same phase as the signal being coupled to the associated sense element, and phase detecting circuit means for providing in sequence a first binary output signal for each control signal of said first phase provided by said signal detecting means and a second binary output signal for each control signal of said second phase provided by said signal detecting means as said input circuits are enabled whereby the set of outputs provided by said phase detecting circuit means represents the angular position of said shaft.

Claim 14

An analog-to-digital converter as set forth in claim 7 in which said energizing member is rotatable by said shaft relative to said input member and in which the configurations of said input elements are substantially the same as the configurations of said signal elements to permit first and second electric fields to be established between said first and second input elements and said first and second signal elements, respectively, by said signals of said first and second phases, said electric fields remaining substantially unchanged as said energizing member is rotated by said shaft.

Claim 15

In an analog-to-digital converter for providing a set of binary output signals coded to represent the angular position of a shaft, signal generating means for providing signals of first and second phases, encoder means including a code member having a plurality of discrete sense elements disposed on a surface thereof in a single annular track, and an energizing member mounted for rotation by said shaft and having stimulus element means disposed on a surface thereof which is adjacent said sense elements for selectively coupling signals of said first phase to certain ones of said sense elements and signals of said second phase to certain others of said sense elements as a function of the angular position of said shaft, and detecting means including a plurality of signal detecting circuits, each of said signal detecting circuits including buffer amplifier means connected to a different one of said sense elements and being operablE when enabled to provide a control signal of the same phase as the signal being coupled to an associated sense element, circuit select means for enabling said signal detecting circuits one at a time, and phase detecting means commonly connected to an output of each of said signal detecting circuits and isolated from said sense elements by said buffer amplifier means, said phase detecting circuit means being responsive to said control signals to provide a sequence of binary coded output signals, including a first binary output signal for each control signal of said first phase provided by said signal detecting circuits and a second binary output signal for each control signal of said second phase provided by said signal detecting circuits as said signal detecting circuits are enabled, whereby the binary coded sequence of output signals provided by said phase detecting circuit means represents the angular position of said shaft.

Claim 16

In an analog-to-digital converter for providing a set of binary output signals coded to represent the angular position of a shaft, signal generating means for providing signals of first and second phases, encoder means including a code member having a plurality of discrete sense elements disposed on a surface thereof in a single annular track, and an energizing member mounted for rotation by said shaft and having stimulus element means disposed on a surface thereof which is adjacent said sense elements for selectively coupling signals of said first phase to certain ones of said sense elements and signals of said second phase to certain others of said sense elements as a function of the angular position of said shaft, and detecting means including a plurality of signal detecting circuits, each of said signal detecting circuits including buffer amplifier means connected to a different one of said sense elements and being operablE when enabled to provide a control signal of the same phase as the signal being coupled to an associated sense element, circuit select means for enabling said signal detecting circuits one at a time, and phase detecting means commonly connected to an output of each of said signal detecting circuits and isolated from said sense elements by said buffer amplifier means, said phase detecting circuit means being responsive to said control signals to provide a sequence of binary coded output signals, including a first binary output signal for each control signal of said first phase provided by said signal detecting circuits and a second binary output signal for each control signal of said second phase provided by said signal detecting circuits as said signal detecting circuits are enabled, whereby the binary coded sequence of output signals provided by said phase detecting circuit means represents the angular position of said shaft.

Claim 17

An analog-to-digital converter as set forth in claim 9 in which said phase detecting circuit means includes reference means for providing a reference signal of one of said phases, and phase comparison means for comparing each of said control signals with said reference signal and providing said first binary output signal when the phases of the signals being compared are the same, and said second binary output signal when the phases of the signals being compared are different.

Claim 18

In an analog-to-digital converter for providing a different set of output signals for each of a plurality of predetermined angular positions of a shaft, signal generating means for providing first and second signals over first and second outputs, and encoder means including a code member having a plurality of sense elements, an input member including a hollow cylinder means having inner and outer conductive surfaces connected to said first and second signal outputs, respectively, of said signal generating means for providing separate conducting paths for said first and second signals, energizing means having first and second stimulus element means and further coupling means including a pair of concentric cylinder members having opposing conductive surfaces spaced apart from one another defining a channel therebetween, one of said conductive surfaces being connected to said first stimulus means and the other conductive surface being connected to said second stimulus means, said input member coupling means and said energizing member coupling means being assembled in an interfitting overlapping relationship with said inner conductive surface overlapping a predetermined length of said one conductive surface but spaced apart from said one surface permitting said first signals to be coupled to said first stimulus means, and said outer conductive surface overlapping a different predetermined length of said other conductive surface but spaced apart from said other surface permitting said second signals to be coupled to said second stimulus means, said energizing member being mounted on said shaft for rotation thereby with said stimulus means being in overlying relationship with said code member to effect selective coupling of said signals to said sense elements as a function of the angular position of said shaft to thereby effect the generation of a different one of said sets of output signals over said sense elements for each predetermined angular position of said shaft.

Claim 19

In an analog-to-digital converter for providing a different set of output signals for each of a plurality of predetermined angular positions of a shaft, signal generating means for providing first and second signals over first and second outputs, and encoder means including a code member having a plurality of sense elements, an input member including a hollow cylinder means having inner and outer conductive surfaces connected to said first and second signal outputs, respectively, of said signal generating means for providing separate conducting paths for said first and second signals, energizing means having first and second stimulus element means and further coupling means including a pair of concentric cylinder members having opposing conductive surfaces spaced apart from one another defining a channel therebetween, one of said conductive surfaces being connected to said first stimulus means and the other conductive surface being connected to said second stimulus means, said input member coupling means and said energizing member coupling means being assembled in an interfitting overlapping relationship with said inner conductive surface overlapping a predetermined length of said one conductive surface but spaced apart from said one surface permitting said first signals to be coupled to said first stimulus means, and said outer conductive surface overlapping a different predetermined length of said other conductive surface but spaced apart from said other surface permitting said second signals to be coupled to said second stimulus means, said energizing member being mounted on said shaft for rotation thereby with said stimulus means being in overlying relationship with said code member to effect selective coupling of said signals to said sense elements as a function of the angular position of said shaft to thereby effect the generation of a different one of said sets of output signals over said sense elements for each predetermined angular position of said shaft.

Claim 20

An analog-to-digital converter as set forth in claim 11 in which the ratio of the diameters of said cylinder members is proportional to the inverse ratio of the lengths of respective conductive surfaces overlapped by the conductive surfaces of said hollow cylinder means.

Claim 21

In an analog to digital converter for providing a different set of output signals for each of a plurality of predetermined angular positions of a shaft, signal generating means for providing first and second signals over first and second outputs, and encoder means including a code member having a plurality of sense elements, An input member including a first planar element having a first pair of concentric rings of conductive material, the inner conductive ring being connected to said first output of said signal generating means and the outer one of said conductive rings being connected to said second output of said signal generating means, and an energizing member including a second planar element having first and second stimulus means disposed on a first surface thereof and a further pair of concentric rings of conductive material on a second surface thereof, the inner conductive ring being connected to said first stimulus means and the outer conductive ring being connected to said second stimulus means, said first planar element being mounted in a fixed position in overlying relationship with said energizing member with said first pair of conductive rings adjacent to but spaced apart from said second pair of conductive rings permitting said first signals to be coupled over said inner rings to said first stimulus means and said second signals to be coupled over said outer rings to said second stimulus means, said second planar element being mounted for rotation by said shaft relative to said code member in overlying relationship therewith to effect selective coupling of said signals to said sense elements as a function of the angular position of said shaft to thereby provide a different one of said sets of output signals over said sense elements for each predetermined angular position of said shaft.

Claim 22

In an analog to digital converter for providing a different set of output signals for each of a plurality of predetermined angular positions of a shaft, signal generating means for providing first and second signals over first and second outputs, and encoder means including a code member having a plurality of sense elements, An input member including a first planar element having a first pair of concentric rings of conductive material, the inner conductive ring being connected to said first output of said signal generating means and the outer one of said conductive rings being connected to said second output of said signal generating means, and an energizing member including a second planar element having first and second stimulus means disposed on a first surface thereof and a further pair of concentric rings of conductive material on a second surface thereof, the inner conductive ring being connected to said first stimulus means and the outer conductive ring being connected to said second stimulus means, said first planar element being mounted in a fixed position in overlying relationship with said energizing member with said first pair of conductive rings adjacent to but spaced apart from said second pair of conductive rings permitting said first signals to be coupled over said inner rings to said first stimulus means and said second signals to be coupled over said outer rings to said second stimulus means, said second planar element being mounted for rotation by said shaft relative to said code member in overlying relationship therewith to effect selective coupling of said signals to said sense elements as a function of the angular position of said shaft to thereby provide a different one of said sets of output signals over said sense elements for each predetermined angular position of said shaft.

Claim 23

An analog-to-digital converter as set forth in claim 13 wherein the areas of conductive material which comprise the inner and outer rings of said first and second pairs are equal.

Claim 24

In an analog-to-digital converter for providing a different logic word for each of a plurality of predetermined angular positions of a shaft, encoder means for providing a set of output signals of first and second phases in a pattern related to the angular position of said shaft, the pattern being different for each predetermined position for said shaft, output means including signal detecting means having a plurality of signal detecting circuits, each output signal of a given set being extended to a different one of said signal detecting circuits and each signal detecting circuit being operable when enabled to provide a control signal of the same phase as the output signal extended thereto, reference means for providing a reference signal of one of said phases, and a phase comparison flip flop having a first input connected to an output of said signal detecting means and a second input connected to an output of said reference means for comparing each control signal provided by said signal detecting means with said reference signal to provide a first logic level output signal whenever the phases of the compared signals are the same and a second logic level output signal whenever the phases of the compared signals are different to thereby generate a correspondingly different logic word for each pattern of signals extended to said signal detecting means.

Claim 25

In an analog-to-digital converter for providing a different logic word for each of a plurality of predetermined angular positions of a shaft, encoder means for providing a set of output signals of first and second phases in a pattern related to the angular position of said shaft, the pattern being different for each predetermined position for said shaft, output means including signal detecting means having a plurality of signal detecting circuits, each output signal of a given set being extended to a different one of said signal detecting circuits and each signal detecting circuit being operable when enabled to provide a control signal of the same phase as the output signal extended thereto, reference means for providing a reference signal of one of said phases, and a phase comparison flip flop having a first input connected to an output of said signal detecting means and a second input connected to an output of said reference means for comparing each control signal provided by said signal detecting means with said reference signal to provide a first logic level output signal whenever the phases of the compared signals are the same and a second logic level output signal whenever the phases of the compared signals are different to thereby generate a correspondingly different logic word for each pattern of signals extended to said signal detecting means.

Claim 26

An analog-to-digital converter as set forth in claim 15 in which said output means further includes circuit select means for enabling said signal detecting circuits one at a time to provide said control signals for said phase comparison flip flop.