System and method for sampling rate adjustment of digital radio receiver
View Patent ↗Methods and systems for adjusting a sampling rate of a digital radio receiver are disclosed that comprise the steps of receiving from a decoder a first frame of data having a first number of samples; determining at the digital radio receiver a phase difference between a receiver clock and a transmitter clock; generating at the digital radio receiver a second frame of data having a second number of samples, wherein the second number of samples depends on the phase difference between the receiver clock and the transmitter clock such that the second number of samples is less than the first number of samples if the transmitter clock is ahead of the receiver clock, and the second number of samples is greater than the first number of samples if the receiver clock is ahead of the transmitter clock; outputting the second frame of data having the second number of samples; and requesting a next frame of data from the decoder at a time that is earlier than a processing time for the first number of samples if the transmitter clock is ahead of the receiver clock and at a time that is later than the processing time for the first number of samples if the receiver clock is ahead of the transmitter clock such that the next frame of data from the decoder and a next transmitter frame are synchronized, and wherein whether the second number of samples is greater than or less than the first number of samples is determined by whether the sampling rate is increased or decreased.
1. A method of adjusting a sampling rate of a digital radio receiver comprising the steps of:
receiving from a decoder a first frame of data having a first number of samples;
determining at the digital radio receiver a phase difference between a receiver clock and a transmitter clock;
generating at the digital radio receiver a second frame of data having a second number of samples, wherein the second number of samples depends on the phase difference between the receiver clock and the transmitter clock such that
the second number of samples is less than the first number of samples if the transmitter clock is ahead of the receiver clock, and
the second number of samples is greater than the first number of samples if the receiver clock is ahead of the transmitter clock;
outputting the second frame of data having the second number of samples; and
requesting a next frame of data from the decoder at a time that is earlier than a processing time for the first number of samples if the transmitter clock is ahead of the receiver clock and at a time that is later than the processing time for the first number of samples if the receiver clock is ahead of the transmitter clock, such that the next frame of data from the decoder and a next transmitter frame are synchronized, wherein whether the second number of samples is greater than or less than the first number of samples is determined by whether the sampling rate is increased or decreased.
2. The method of claim 1 wherein the first frame of data is interpolated to generate the second frame of data.
3. The method of claim 1 wherein the first number of samples is constant.
4. The method of claim 3 wherein the first number of samples is 2048.
5. The method of claim 1 wherein the second number of samples is one less than the first number of samples if the transmitter clock is ahead of the receiver clock.
6. The method of claim 1 wherein the second number of samples is one more than the first number of samples if the receiver clock is ahead of the transmitter clock.
7. The method of claim 1 wherein outputting the second frame of data comprises storing the data in a memory using direct memory access.
8. The method of claim 1 wherein the first frame of data is digital audio data.
9. The method of claim 8 wherein the decoder is an advanced audio coding decoder.
10. The method of claim 1 wherein the first frame of data is digital video data.
11. The method of claim 10 wherein the decoder is a H.264 decoder.
12. A digital radio receiver system configured to adjust a sampling rate comprising:
a processing system; and
a memory coupled to the processing system, wherein the processing system is configured to execute steps comprising:
receiving from a decoder a first frame of data having a first number of samples;
determining at the digital radio receiver a phase difference between a receiver clock and a transmitter clock;
generating at the digital radio receiver a second frame of data having a second number of samples, wherein the second number of samples depends on the phase difference between the receiver clock and the transmitter clock such that
the second number of samples is less than the first number of samples if the transmitter clock is ahead of the receiver clock, and
the second number of samples is greater than the first number of samples if the receiver clock is ahead of the transmitter clock;
outputting the second frame of data having the second number of samples; and
requesting a next frame of data from the decoder at a time that is earlier than a processing time for the first number of samples if the transmitter clock is ahead of the receiver clock and at a time that is later than the processing time for the first number of samples if the receiver clock is ahead of the transmitter clock, such that the next frame of data from the decoder and a next transmitter frame are synchronized, wherein whether the second number of samples is greater than or less than the first number of samples is determined by whether the sampling rate is increased or decreased.
13. The digital radio receiver system of claim 12 wherein the first frame of data is interpolated to generate the second frame of data.
14. The digital radio receiver system of claim 12 wherein the first number of samples is constant.
15. The digital radio receiver system of claim 14 wherein the first number of samples is 2048.
16. The digital radio receiver system of claim 12 wherein the second number of samples is one less than the first number of samples if the transmitter clock is ahead of the receiver clock.
17. The digital radio receiver system of claim 12 wherein the second number of samples is one more than the first number of samples if the receiver clock is ahead of the transmitter clock.
18. The digital radio receiver system of claim 12 wherein outputting the second frame of data comprises storing the data in a memory using direct memory access.
19. The digital radio receiver system of claim 12 wherein the first frame of data is digital audio data.
20. The digital radio receiver system of claim 19 wherein the decoder is an advanced audio coding decoder.
21. The digital radio receiver system of claim 12 wherein the first frame of data is digital video data.
22. The digital radio receiver system of claim 21 wherein the decoder is a H.264 decoder.
23. A tangible computer readable medium comprising computer program instructions adapted to cause a processing system to execute steps comprising:
receiving from a decoder a first frame of data having a first number of samples;
determining at the digital radio receiver a phase difference between a receiver clock and a transmitter clock;
generating at the digital radio receiver a second frame of data having a second number of samples, wherein the second number of samples depends on the phase difference between the receiver clock and the transmitter clock such that
the second number of samples is less than the first number of samples if the transmitter clock is ahead of the receiver clock, and
the second number of samples is greater than the first number of samples if the receiver clock is ahead of the transmitter clock;
outputting the second frame of data having the second number of samples; and
requesting a next frame of data from the decoder at a time that is earlier than a processing time for the first number of samples if the transmitter clock is ahead of the receiver clock and at a time that is later than the processing time for the first number of samples if the receiver clock is ahead of the transmitter clock, such that the next frame of data from the decoder and a next transmitter frame are synchronized, wherein whether the second number of samples is greater than or less than the first number of samples is determined by whether the sampling rate is increased or decreased.
24. The tangible computer readable medium of claim 23 wherein the first frame of data is interpolated to generate the second frame of data.
25. The tangible computer readable medium of claim 23 wherein the first number of samples is constant.
26. The tangible computer readable medium of claim 25 wherein the first number of samples is 2048.
27. The tangible computer readable medium of claim 23 wherein the second number of samples is one less than the first number of samples if the transmitter clock is ahead of the receiver clock.
28. The tangible computer readable medium of claim 23 wherein the second number of samples is one more than the first number of samples if the receiver clock is ahead of the transmitter clock.
29. The tangible computer readable medium of claim 23 wherein outputting the second frame of data comprises storing the data in a memory using direct memory access.
30. The tangible computer readable medium of claim 23 wherein the first frame of data is digital audio data.
31. The tangible computer readable medium of claim 30 wherein the decoder is an advanced audio coding decoder.
32. The tangible computer readable medium of claim 23 wherein the first frame of data is digital video data.
33. The tangible computer readable medium of claim 32 wherein the decoder is a H.264 decoder.