ANALOG-TO-DIGITAL CONVERTER EMPLOYING ELECTROSTATIC SIGNAL COUPLING APPARATUS

• US 3,766,544 A
• Filed: 11/19/1971
• Issued: 10/16/1973
• Est. Priority Date: 11/19/1971
• Status: Expired due to Term

• Current Assignee: James E. Batz
• Original Assignee: James E. Batz
• Inventors: Batz, James E.
• Primary Examiner(s): Wilbur, Maynard R.
• Assistant Examiner(s): Glassman, Jeremiah
• Application Number:
  US05/200,369
• Time in Patent Office: 697 Days
• Field of Search: 340/347P,347DD 317/16,253 334/81,82
• US Class Current: 341/7
• CPC Class Codes: G01D 5/2412 by varying overlap
• CPC Class Codes: H03M 1/00 Analogue/digital conversion; Digital/analogue conversion conversion of analogue values to or from differential modulation H03M3/00
• CPC Class Codes: H03M 1/22 pattern-reading type

Abstract

An analog-to-digital converter includes an electrostatic encoder having a signal sensor vane mounted for rotation by a shaft to overlie different excitation segments of an excitation member at each of a plurality of predetermined positions of the shaft to be indicated, and signal generating means for selectively extending signals of different phases to groups of excitation segments, the signals being coupled to an output circuit over the sensor vane as a function of the position of the shaft thereby providing a different multi-bit output code over the output circuit for each predetermined position of the shaft.

Claims

1. In an analog-to-digital converter including an encoder for providing a different set of outputs for each of a plurality of predetermined angular positions of a shaft, excitation means including a plurality of excitation segments each representing a different one of said predetermined shaft positions, a signal coupling member mounted for rotation by said shaft to overlie different ones of said segments at each shaft position to permit signal coupling therebetween, output means coupled to said signal coupling member, and energizing means for extending at least one excitation signal to said segments in a multistep sequence such that said excitation signal is applied to a different one of said segments in successive steps of said sequence, whereby said excitation signal is coupled over said signal coupling member from one of said segments to said output means at a particular step of the sequence to thereby indicate the angular position of said shaft.

2. In an analog-to-digital converter including an encoder for providing a different set of outputs for each of a plurality of predetermined angular positions of a shaft, excitation means including a plurality of excitation segments of an electrically conductive material, signal distributing means for applying excitation signals to said segments in a multistep sequence such that said excitation signals are applied to a different plurality of said segments in successive steps of said sequence, output means and signal coupling means including a signal coupling member of an electrically conductive material, mounted for rotation by said shaft to overlie a segment of a different one of said segments at each shaft position, whereby said excitation signals are coupled over said signal coupling member from the segment adjacent said signal coupling member to said output means in a sequence representing the angular position of said shaft, and means in said output means responsive to excitation signals coupled thereto to provide a set of signal outputs representing the angular position of said shaft.

3. An analog-to-digital converter as set forth in claim 2 wherein said signal distributing means includes sigNal generating means for providing excitation signals of first and second phases.

4. An analog-to-digital converter as set forth in claim 3 wherein said signal distributing means includes gating means including a plurality of gate circuits each connected between said signal generating means and a different one of said excitation segments, and control means for selectively enabling said gate circuits in groups to sequentially extend excitation signals to a different plurality of excitation segments.

5. An analog-to-digital converter as set forth in claim 4 wherein said excitation means includes an excitation member, said excitation segments being disposed on a surface of said excitation member in a single annular track.

6. An analog-to-digital converter as set forth in claim 5 wherein at least one of said gating circuits is operable when enabled to extend signals of said first phase to a first segment of one of said plurality of segments and signals of said second phase to two other segments of said one plurality of said segments whereby signals of the first phase are coupled to said signal coupling member whenever said signal coupling member is adjacent said first segment, signals of said second phase are coupled to said signal coupling member whenever said signal coupling member is adjacent said second segment, and signals of both phases are coupled to said signal coupling member whenever said signal coupling member is adjacent a segment intermediate said first and second segments.

7. In an analog-to-digital converter including an encoder for providing a different set of outputs for each of a plurality of angular positions of a shaft, excitation means including an excitation member having a plurality of excitation segments of an electrically conductive material disposed on a surface thereof, signal distributing means for applying excitation signals of different phases to said segments in a multistep sequence such that said excitation signals are applied to a different plurality of said segments in successive steps of said sequence, a signal coupling member of an electrically conductive material mounted for rotation by said shaft to overlie a different one of said segments at each shaft position, whereby excitation signals of different phases are coupled to said signal coupling member from the segment adjacent said signal coupling member in a sequence representing the angular position of the shaft.

8. An analog-to-digital converter as set forth in claim 7 wherein said encoder includes output means coupled to said signal coupling member, said output means being responsive to signals of a first phase coupled thereto over said signal coupling member to provide a first output signal and responsive to signals of a second phase coupled thereto over said signal coupling member to provide a second output signal whereby a set of output signals representing the angular position of the shaft is provided over said output means as said excitation signals are sequentially applied to said segments.

9. An analog-to-digital converter as set forth in claim 7 wherein said output means comprises a signal sensing member including a first hollow cylinder of a first diameter and wherein said signal coupling member includes a second cylinder of a diameter less than the first diameter, mounted for rotation within said first cylinder in spaced relation therewith with at least a portion of the outer wall of said second cylinder overlapping at least a portion of the inner wall of said first cylinder to permit signal coupling therebetween.

10. An analog-to-digital converter as set forth in claim 9 including electrostatic shielding means interposed between said excitation member and said signal sensing cylinder to minimize electrostatic coupling between said excitation segments and said signal sensing cylinder.

11. An analog-to-digital converter as set forth in claim 9 wherein each of said excitation segments comprise a planar element and said signal coupling member comprisEs a flat vane member electrically connected to said second cylinder and extending therefrom in a parallel spaced relationship with the excitation segments on the surface of said excitation member.

12. In an analog-to-digital converter including an encoder for providing a different set of outputs for each of a plurality of angular positions of a shaft, excitation means including an excitation member having a plurality of excitation segments of an electrically conductive material, signal distributing means for applying excitation signals to a plurality of groups of said segments in a predetermined sequence, said signal distributing means including means for providing excitation signals of a first phase at a first output thereof and for providing excitation signals of a second phase at a second output thereof and gating means for extending signals of said first phase to one of the segments of each group in said predetermined sequence and for extending excitation signals of said second phase to a pair of other segments of each group in said predetermined sequence, a signal sensing member of an electrically conductive material, and signal coupling means including a signal coupling member of an electrically conductive material mounted for rotation by said shaft to overlie a segment of a different one of said groups of segments at each shaft position to be indicated, said signal coupling member being operable to couple excitation signals of said first and second phases from the segment adjacent said signal coupling member to said signal sensing member in a sequence representing the angular position of the shaft.

13. An analog-to-digital converter as set forth in claim 12 wherein said signal distributing means further includes control means for controlling said gating means to select the segments to which excitation signals are extended at each step of said sequence.

14. An analog-to-digital converter as set forth in claim 13 wherein said gating means includes a plurality of gate circuits each having a first input connected to the first output of said signal generating means, a second input connected to the second output of said signal generating means, an output connected to a different one of said segments and a plurality of enabling inputs connected to outputs of said control means.

15. In an analog-to-digital converter, an encoder for providing 20 output words representing the coding for 10 digit positions of a shaft and 10 positions intermediate said digit positions, said encoder comprising an excitation member having 10 excitation segments disposed on a surface thereof in a single annular track, each segment representing a different one of said digit positions, signal distributing means for extending excitation signals to a different group of three of said segments in successive steps of at least a ten step sequence, output means including an output circuit and signal coupling means including a signal coupling member mounted for rotation by said shaft to overlie a different one of said segments at each digit position of said shaft, whereby the excitation signals are coupled to the output circuit at steps of the sequence in which excitation signals are extended to the segment adjacent the signal coupling member.

16. An analog-to-digital converter as set forth in claim 15 wherein said signal distributing means includes means for providing signals of a first and a second phase and means for extending signals of said first phase to one of the segments of each group in sequence and for extending signals of said second phase to two other segments of each group in sequence.

17. An analog-to-digital converter as set forth in claim 16 wherein a first sequence of signals of first and second phases is coupled to said output circuit to indicate each digit position and wherein a second sequence of signals of first and second phases is coupled to said output circuit to indicate positions intermediate a pair of adjacent digit positions.

18. In an analog-to-digital converter including an encoder for providing a different set of output signals for each of a plurality of predetermined angular positions of a shaft, selector switch means having access to a group of circuits including selection means for simultaneously selecting a plurality of said circuits and extending energization signals to the selected plurality of circuits, and sequence means for stepping said selection means to successively select a different plurality of said circuits, sensor means mounted for rotation by said shaft to a plurality of different positions, and means for providing a set of output signals which is dependent upon the plurality of circuits which are energized at the point of location of the sensor means.

19. In an analog-to-digital converter including an encoder for providing a different set of outputs for each of a plurality of predetermined angular positions of a shaft, excitation means including a plurality of excitation segments, signal distributing means including select means for simultaneously selecting a plurality of said excitation segments and extending excitation signals to the selected plurality of said excitation segments and sequencing means for controlling said select means to successively select a different plurality of said excitation segments, and sensor means mounted for rotation by said shaft to overlie a different one of said excitation segments at different predetermined positions of said shaft whereby, when the excitation segment adjacent said sensor means is selected by said select means, excitation signals are coupled to said sensor means in a sequence representing the angular position of said shaft.