LOW POWER SLICER-BASED DEMODULATOR FOR PPM

• US 20090251208A1
• Filed: 04/08/2008
• Published: 10/08/2009
• Est. Priority Date: 04/08/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Lee, Chong U., Lerstaveesin, Supisa, Ekbal, Amal, Julian, David Jonathan, Shi, Jun
• Granted Patent: US 7,868,689 B2
• Time in Patent Office: Days
• US Class Current: 329/313
• CPC Class Codes: H04B 1/71637 Receiver aspects H04B1/7183 takes precedence
• CPC Class Codes: H04B 14/026 using pulse time characteristics modulation, e.g. width, position, interval
• CPC Class Codes: H04L 25/4902 Pulse width modulation; Pulse position modulation

Abstract

An apparatus and method for communications is disclosed. The apparatus includes a slicer configured to generate samples of a signal carrying information, and a demodulator having a digital integrator configured to integrate the samples, the demodulator being further configured to recover from the integrated samples data representative of the information carried by the signal.

Claims

1. An apparatus, comprising:

a slicer configured to generate samples of a signal carrying information; and

a demodulator having a digital integrator configured to integrate the samples, the demodulator being further configured to recover from the integrated samples data representative of the information carried by the signal.

2. The apparatus of claim 1 wherein the signal is a pulse position modulated signal.

3. The apparatus of claim 2 wherein the digital integrator is configured to accumulate the samples at first and second position hypotheses based on the pulse position modulated signal.

4. The apparatus of claim 3 wherein the digital integrator comprises a first accumulator configured to accumulate the samples at the first position hypothesis and a second accumulator configured to accumulate the samples at the second position hypothesis.

5. The apparatus of claim 3 wherein the demodulator further comprises a subtractor configured to compute a difference between the accumulated samples at the first and second position hypotheses.

6. The apparatus of claim 5 wherein the information carried by the signal is encoded, and wherein the data recovered by the demodulator includes a soft decision comprising the difference computed by the subtractor.

7. The apparatus of claim 5 wherein the information carried by the signal is uncoded, and wherein the data recovered by the demodulator includes a hard decision based on the difference computed by the subtractor.

8. The apparatus of claim 7 wherein the demodulator further comprises a comparator configured to generate the hard decision by comparing the difference computed by the subtractor with a threshold.

9. The apparatus of claim 3 wherein the digital integrator is further configured to vary a time period for at least one of the first and second position hypotheses.

10. The apparatus of claim 1 wherein the slicer is configured to vary a sampling frequency for sampling the signal.

11. The apparatus of claim 1 wherein the slicer comprises a 1-bit slicer.

12. The apparatus of claim 1 wherein the slicer comprises an N-bit slicer, N being an integer greater than one.

13. The apparatus of claim 1 further comprising a squarer configured to perform a squaring operation on the signal, wherein the samples are generated from the squared signal.

14. The apparatus of claim 13 further comprising a low pass filter configured to filter the squared signal.

15. A method for wireless communications, comprising:

generating samples of a signal carrying information;

integrating the samples; and

recovering from the integrated samples data representative of the information carried by the signal.

16. The method of claim 15 wherein the signal is a pulse position modulated signal.

17. The method of claim 16 wherein the integrating of the samples comprises accumulating the samples at a first position hypothesis and accumulating the samples at a second position hypothesis based on the pulse position modulated signal.

18. The method of claim 17 wherein the recovery of the data comprises computing a difference between the accumulated samples at the first and second position hypotheses.

19. The method of claim 18 wherein the information carried by the signal is encoded, and wherein the recovery of the data includes making a soft decision comprising the computed difference.

20. The method of claim 18 wherein the information carried by the signal is uncoded, and wherein the recovery of the data includes making a hard decision based on the computed difference.

21. The method of claim 20 wherein the making of the hard decision comprises comparing the computed difference with a threshold.

22. The method of claim 17 wherein the integrating of the samples further comprises varying a time period for at least one of the first and second position hypotheses.

23. The method of claim 15 wherein the generating of the samples comprises varying a sampling frequency for sampling the signal.

24. The method of claim 15 further comprising squaring the signal, wherein the samples are generated from the squared signal.

25. The apparatus of claim 24 further comprising low pass filtering the squared signal.

26. An apparatus, comprising:

means for generating samples of a signal carrying information;

means for digitally integrating the samples; and

means for the recovering from the integrated samples data representative of the information carried by the signal.

27. The apparatus of claim 26 wherein the signal is a pulse position modulated signal.

28. The apparatus of claim 27 wherein the means for digitally integrating the samples comprises means for accumulating the samples at first and second position hypotheses.

29. The apparatus of claim 28 wherein the means for digitally integrating the samples further comprises means for accumulating the samples at the first position hypothesis and means for accumulating the samples at the second position hypothesis.

30. The apparatus of claim 28 wherein the means for recovering the data comprises means for computing a difference between the accumulated samples at the first and second position hypotheses.

31. The apparatus of claim 30 wherein the information carried by the signal is encoded, and wherein the means for the recovering the data further comprises means for making a soft decision comprising the computed difference.

32. The apparatus of claim 30 wherein the information carried by the signal is uncoded, and wherein the means for the recovering the data further comprises means for making a hard decision based on the computed difference.

33. The apparatus of claim 32 wherein the means for making a hard decision comprises means for comparing the computed difference with a threshold.

34. The apparatus of claim 28 further comprising means for varying a time period for at least one of the first and second position hypotheses.

35. The apparatus of claim 26 wherein the means for generating the samples comprises means for varying a sampling frequency for sampling the signal.

36. The apparatus of claim 26 wherein the means for generating samples comprises a 1-bit slicer.

37. The apparatus of claim 26 wherein the means for generating samples comprises an N-bit slicer, N being an integer greater than one.

38. The apparatus of claim 26 further comprising means for performing a squaring operation on the signal, wherein the samples are generated from the squared signal.

39. The apparatus of claim 38 further comprising means for low pass filtering the squared signal.

40. A computer-program product for wireless communications, comprising:

computer-readable medium comprising codes executable to integrate the samples of a signal carrying information, and recover from the integrated samples data representative of the information carried by the signal.

41. A headset, comprising:

a slicer configured to generate samples of a signal carrying information;

a demodulator having a digital integrator configured to integrate the samples, the demodulator being further configured to recover from the integrated samples data representative of the information carried by the signal; and

a transducer configured to generate sound based on the data.

42. A watch, comprising:

a slicer configured to generate samples of a signal carrying information;

a demodulator having a digital integrator configured to integrate the samples, the demodulator being further configured to recover from the integrated samples data representative of the information carried by the signal; and

a user interface configured to provide an indication based on the data.

43. A sensing device, comprising:

a slicer configured to generate samples of a signal carrying information;

a demodulator having a digital integrator configured to integrate the samples, the demodulator being further configured to recover from the integrated samples data representative of the information carried by the signal; and

a sensor configured adapted to generate data based on the data from the demodulator.