Propagation delay compensation and interpolation filter

1. A propagation delay compensation circuit comprising:

a first low pass filter configured to receive a digital input and to reduce noise of the digital input comprising a measured angular position;

a first differentiator configured to receive a filtered digital input comprising the measured angular position and to calculate a speed from a difference in time of the measured angular position and a previous angular position;

a second low pass filter configured to reduce noise from the speed;

a second differentiator configured to receive a filtered speed and to calculate acceleration using a difference in time of the filtered speed and a previous speed;

a third low pass filter configured to reduce noise of the acceleration; and

a delay compensator configured to receive the filtered digit input, the filtered speed, and a filtered acceleration, and to calculate a propagation delay compensated digital output.

2. The propagation delay compensation circuit according to claim 1 , further comprising an extrapolation generator configured to receive a filtered acceleration and compute an extrapolated angular position.

3. The propagation delay compensation circuit according to claim 2 , further comprising a pre-processing block configured to:

receive the digital input comprising the measured angular position;

determine the measured angular position is in an acceptable range, then send the digital input comprising the measured angular position to the first low band pass filter; and

determine the measured angular position is not in an acceptable range, then send a digital input comprising the extrapolated angular position to the first low band pass filter.

4. The propagation delay compensation circuit according to claim 3 , wherein the pre-processing block is configured to determine the digital input is not received, then send a digital output comprising the extrapolated angular position to the first low band pass filter.

5. The propagation delay compensation circuit according to claim 2 , further comprising a pre-processing block configured to:

receive the digital input comprising the measured angular position;

determine the digital input comprising the measured angular position is received, then send the digital input comprising the measured angular position to the first low band pass filter; and

determine the digital input comprising the measured angular position is not received, then send a digital input comprising the extrapolated angular position to the first low band pass filter.

6. The propagation delay compensation circuit according to claim 2 , further comprising a pre-processing block configured to:

receive the digital input comprising the measured angular position;

compare the measured angular position and the extrapolated angular position for best fit; and

send a digital input comprising the best-fit angular position to the first low band pass filter.

7. The propagation delay compensation circuit according to claim 1 , wherein the propagation delay compensated digital output is a propagation delay compensated measured angular position.

8. The propagation delay compensation circuit according to claim 2 wherein the propagation delay compensated digital output is a propagation delay compensated extrapolated angular position.

9. The propagation delay compensation circuit according to claim 1 , wherein the propagation delay compensated digital output is the filtered measured angular position.

10. A system comprising:

a sensor configured to measure an angular position of a rotating object;

an analog to digital converter configured to receive the angular position and convert the angular position into a digital input comprising a measured angular position; and

a propagation delay compensation circuit comprising:

a first low pass filter configured to receive the digital input comprising the measured angular position and to reduce noise of the measured angular position;

a first differentiator configured to receive a filtered measured angular position and to calculate a speed from a difference in time of the filtered measured angular position and a previous angular position;

a second low pass filter configured to reduce noise from the speed;

a second differentiator configured to receive a filtered speed and to calculate acceleration using a difference in time of the filtered speed and a previous speed;

a third low pass filter configured to reduce noise of the acceleration; and

a delay compensator configured to receive the filtered digit input, the filtered speed, and a filtered acceleration, and to calculate a propagation delay compensated digital output.

11. The system according to claim 10 , further comprising an analog signal processor configured to receive the angular position from the sensor; process an electrical signal comprising the angular position; and send a processed angular position to the analog to digital converter.

12. The system according to claim 11 , wherein the process an electrical signal is at least one of filtering the electrical signal, reducing noise of the electrical signal, amplifying the electrical signal, and multiplexing the electrical signal.

13. The system according to claim 10 , further comprising a digital signal processor configured to receive the digital input comprising the measured angular position; process an digital signal comprising the measured angular position; and send a processed digital input comprising the measured angular position to the propagation delay compensation circuit.

14. The system according claim 10 , wherein the sensor comprises a transducer, an optical detector, a magnetic detector, an inductive detector, a capacitive detector, or a Hall effect detector.

15. The system according to claim 10 , wherein the propagation delay compensated digital output is propagation delay compensated measured angular position.

16. Method of calculating propagation delay compensation, the method comprising:

receiving a digital input comprising a measured angular position of a rotating object;

reducing noise of the digital input comprising the measured angular position;

calculating a speed from a difference in time of the filtered measured angular position and a previous angular position;

reducing noise from the speed;

calculating an acceleration using a difference in time of a filtered speed and a previous speed;

reducing noise of the acceleration;

receiving the filtered measured angular position, the filtered speed, and a filtered acceleration in a delay compensator; and

calculating, in the a delay compensator, a propagation delay compensated digital output.

17. The method according to claim 16 , further comprising:

comparing the measured angular position to a previous angular position of the rotating object;

determining the measured angular position is not valid based on the comparing; and

replacing the measured angular position with an extrapolated angular position based on the previous angular position.

18. The method according to claim 16 , further comprising:

collecting an angular position with a sensor;

sending an analog signal comprising the measured angular position to an analog to digital converter; and

converting the analog signal into a digital output comprising the measured angular position.

19. The method according to claim 16 further comprising sending the propagation delay compensated digital output is a controller.

20. The method according to claim 16 , wherein the propagation delay compensated digital output is a propagation delay compensated measured angular position.