Noise measurement for measured displacement
An apparatus including a first plurality of electrodes and a second plurality of electrodes is disclosed. Each electrode of the first plurality of electrodes is configured to measure an electric field associated with a position of a moving object. The second plurality of electrodes is disposed further away from the moving object in comparison to the first plurality of electrodes. The second plurality of electrodes is configured to measure a signal associated with ambient noise.
1. A device comprising:
a first plurality of electrodes, wherein each electrode of the first plurality of electrodes is configured to measure an electric field associated with a position of a rotating object;
a second plurality of electrodes, wherein the second plurality of electrodes is configured to measure a signal associated with ambient noise, wherein the first plurality of electrodes forms a first ring structure and the second plurality of electrodes forms a second ring structure, wherein a diameter associated with the second ring structure is greater than a diameter of the first ring structure; and
a sensing circuitry configured to receive signals from the first plurality of electrodes and the second plurality of electrodes, wherein the sensing circuitry is configured to determine displacement associated with the rotating object, and wherein the sensing circuitry is further configured to determine the ambient noise based on the signal from the second plurality of electrodes.
2. The device of claim 1 , wherein variations between electric field measurements of electrodes of the first plurality of electrodes is used by the sensing circuitry to determine the displacement.
3. The device of claim 2 further comprising:
a difference amplifier configured to remove the ambient noise from the measured displacement.
4. The device of claim 1 , wherein the first plurality of electrodes and the second plurality of electrodes are disposed in vias formed in a printed circuit board.
5. The device of claim 1 , wherein at least two electrodes of the second plurality of electrodes are coupled to a floating ring via a trace, wherein the floating ring and the two electrodes of the second plurality of electrodes are disposed within a same layer of a printed circuit board, and wherein the floating ring is disposed between two sensing rings, wherein each sensing ring is disposed in a different layer of the printed circuit board.
6. A printed circuit board comprising:
an inner edge ring of the printed circuit board forming a hollow structure, wherein the inner edge ring is configured to surround a rotating object placed within the hollow structure;
a first plurality of electrodes disposed on the printed circuit board, wherein the first plurality of electrodes is configured to measure electric fields associated with a position of the rotating object; and
a second plurality of electrodes disposed on the printed circuit board, wherein the second plurality of electrodes is disposed further away from the inner edge ring in comparison to the first plurality of electrodes to measure a signal associated with ambient noise, wherein a distance between the second plurality of electrodes and the inner edge ring is selected such that the ambient noise signal measured by the second plurality of electrodes is more dominant than the electric field signals measured by the second plurality of electrodes.
7. The printed circuit board of claim 6 , wherein the first plurality of electrodes forms a first ring structure and the second plurality of electrodes forms a second ring structure, wherein a diameter associated with the second ring structure is greater than a diameter of the first ring structure.
8. The printed circuit board of claim 6 , wherein variations between electric field measurements of electrodes of the first plurality of electrodes is associated with displacement of the rotating object.
9. The printed circuit board of claim 8 further comprising:
a difference amplifier configured to remove the ambient noise from measured displacement of the rotating object.
10. The printed circuit board of claim 6 , wherein the first plurality of electrodes and the second plurality of electrodes are formed within vias.
11. The printed circuit board of claim 6 further comprising:
a first sensing circuit coupled to the first plurality of electrodes, wherein the first sensing circuit is configured to determine displacement of the rotating object; and
a second sensing circuit coupled to the second plurality of electrodes, wherein the second sensing circuit is configured to determine ambient noise based on signals received from the second plurality of electrodes.
12. The printed circuit board of claim 6 , wherein at least two electrodes of the second plurality of electrodes are coupled to a floating ring via a trace, wherein the floating ring and the two electrodes of the second plurality of electrodes are disposed within a same layer of the printed circuit board, and wherein the floating ring is disposed between two sensing rings, wherein each sensing ring is disposed in a different layer of the printed circuit board.
13. An apparatus comprising:
a first plurality of electrodes, wherein each electrode of the first plurality of electrodes is configured to measure an electric field associated with a position of a moving object; and
a second plurality of electrodes disposed further away from the moving object in comparison to the first plurality of electrodes, wherein the second plurality of electrodes is configured to measure a signal associated with ambient noise, wherein the first plurality of electrodes and the second plurality of electrodes are disposed in vias formed in a printed circuit board.
14. The apparatus of claim 13 , wherein the first plurality of electrodes forms a first ring structure and the second plurality of electrodes forms a second ring structure, wherein a diameter associated with the second ring structure is greater than a diameter of the first ring structure.
15. The apparatus of claim 13 , wherein variations between electric field measurements of electrodes of the first plurality of electrodes is associated with displacement of the moving object.
16. The apparatus of claim 15 further comprising:
a difference amplifier configured to remove the ambient noise from measured displacement of the moving object.
17. The apparatus of claim 13 further comprising:
a first sensing circuit coupled to the first plurality of electrodes, wherein the first sensing circuit is configured to determine displacement of the moving object; and
a second sensing circuit coupled to the second plurality of electrodes, wherein the second sensing circuit is configured to determine ambient noise based on signals received from the second plurality of electrodes.
18. The apparatus of claim 13 , wherein at least two electrodes of the second plurality of electrodes are coupled to a floating ring via a trace, wherein the floating ring and the two electrodes of the second plurality of electrodes are disposed within a same layer of a printed circuit board, and wherein the floating ring is disposed between two sensing rings, wherein each sensing ring is disposed in a different layer of the printed circuit board.
19. An apparatus comprising:
a first plurality of electrodes, wherein each electrode of the first plurality of electrodes is configured to measure an electric field associated with a position of a moving object; and
a second plurality of electrodes disposed further away from the moving object in comparison to the first plurality of electrodes, wherein the second plurality of electrodes is configured to measure a signal associated with ambient noise, wherein at least two electrodes of the second plurality of electrodes are coupled to a floating ring via a trace, wherein the floating ring and the two electrodes of the second plurality of electrodes are disposed within a same layer of a printed circuit board, and wherein the floating ring is disposed between two sensing rings, wherein each sensing ring is disposed in a different layer of the printed circuit board.