Efficient two-stage asynchronous sample-rate converter

Patent metadata

Field	Value
Publication number	US-9258011-B2
Application number	US-201314043509-A
Country	US
Kind code	B2
Filing date	Oct 1, 2013
Priority date	Oct 1, 2013
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

Methods and systems consistent with the present invention provide an improved sample-rate converter that overcomes the limitations of conventional sample-rate converters. The improved system comprises a simple asynchronous sample-rate converter and synchronous sample-rate converter. The output of the simple asynchronous sample-rate converter is connected to the input of the synchronous sample-rate converter. In an alternative embodiment, the output of the synchronous sample-rate converter is connected to the input of the simple asynchronous sample-rate converter.

First claim

What is claimed is:

1. A sample-rate converter system, comprising:
a simple asynchronous sample-rate converter having an input and an output; and
a synchronous sample-rate converter having an input and an output, wherein the output of the simple asynchronous sample-rate converter is connected to the input of the synchronous sample-rate converter;
wherein: (1) the synchronous sample-rate converter comprises a full synchronous sample-rate converter; or (2) the simple asynchronous sample-rate converter has an input sample-rate and an output sample-rate, and the ratio of the input sample-rate over the output sample-rate is approximately equal to unity.

2. The system of claim 1 , wherein the synchronous sample-rate converter comprises the full synchronous sample-rate converter.

3. The system of claim 1 , wherein the simple asynchronous sample-rate converter has the input sample-rate and the output sample-rate, and the ratio of the input sample-rate over the output sample-rate is approximately equal to the unity.

4. The system of claim 1 , wherein the simple asynchronous sample-rate converter comprises a sample buffer and a controller.

5. The system of claim 1 , wherein the synchronous sample-rate converter comprises a sample buffer and a controller/calculator.

6. The system of claim 1 , wherein the simple asynchronous sample-rate converter comprises a packet buffer and a controller.

7. The system of claim 1 , wherein the synchronous sample-rate converter comprises a packet buffer and a controller/calculator.

8. A sample-rate converter system, comprising:
a synchronous sample-rate converter having an input and an output; and
a simple asynchronous sample-rate converter having an input and an output, wherein the output of the synchronous sample-rate converter is connected to the input of the simple asynchronous sample-rate converters;
wherein: (1) the synchronous sample-rate converter comprises a full synchronous sample-rate converter; (2) the simple asynchronous sample-rate converter has an input sample-rate and an output sample-rate, and the ratio of the input sample-rate over the output sample-rate is approximately equal to unity; (3) the simple asynchronous sample-rate converter has an input sample-rate and an output sample-rate, and the ratio of the input sample-rate over the output sample-rate is approximately equal to unity; (4) the synchronous sample-rate converter comprises a sample buffer and a controller/calculator; (5) the simple asynchronous sample-rate converter comprises a packet buffer and a controller; or (6) the synchronous sample-rate converter comprises a packet buffer and a controller/calculator.

9. The system of claim 8 , wherein the synchronous sample-rate converter comprises the full synchronous sample-rate converter.

10. The system of claim 8 , wherein the simple asynchronous sample-rate converter has the input sample-rate and the output sample-rate, and the ratio of the input sample-rate over the output sample-rate is approximately equal to the unity.

11. The system of claim 8 , wherein the simple asynchronous sample-rate converter comprises the sample buffer and the controller.

12. The system of claim 8 , wherein the synchronous sample-rate converter comprises the sample buffer and the controller/calculator.

13. The system of claim 8 , wherein the simple asynchronous sample-rate converter comprises the packet buffer and the controller.

14. The system of claim 8 , wherein the synchronous sample-rate converter comprises the packet buffer and the controller/calculator.

15. A method for converting samples at an input sample-rate from a source into an output sample-rate, comprising the steps of:
receiving a plurality of input samples from the source;
converting the plurality of input samples at the input sample-rate to a plurality of intermediate samples at an intermediate sample-rate, wherein the plurality of input samples is converted into the plurality of intermediate samples by inserting a new sample or deleting one of the plurality of input samples, and wherein the ratio of the input sample-rate over the intermediate sample-rate is approximately equal to unity; and
converting the plurality of intermediate samples at the intermediate sample-rate into a plurality of output samples at the output sample-rate, wherein the intermediate sample-rate and the output sample-rate are locked together.

16. The method of claim 15 , further comprising the step of smoothing the samples in close proximity to the inserted or deleted samples.

17. The method of claim 15 , wherein the new sample has the same value as one of the input samples directly adjacent to the new sample.

18. The method of claim 15 , wherein the step of inserting new samples comprises creating new samples using standard curve-fitting techniques.

19. The method of claim 15 , wherein the plurality of intermediate samples is converted into the plurality of output samples using interpolation.

20. The method of claim 15 , wherein the samples are transmitted in packets.

21. A method for converting samples at an input sample-rate from a source into an output sample-rate, comprising the steps of:
receiving a plurality of input samples from the source;
converting the plurality of input samples at the input sample-rate to a plurality of intermediate samples at an intermediate sample-rate, wherein the input sample-rate and the intermediate sample-rate are locked together; and
converting the plurality of intermediate samples at the intermediate sample-rate into a plurality of output samples at the output sample-rate, wherein the plurality of intermediate samples is converted into the plurality of output samples by inserting a new sample or deleting one of the plurality of intermediate samples, and wherein the ratio of the intermediate sample-rate over the output sample-rate is approximately equal to unity.

22. The method of claim 21 , further comprising the step of smoothing the samples in close proximity to the inserted or deleted samples.

23. The method of claim 21 , wherein the new sample has the same value as one of the intermediate samples directly adjacent to the new sample.

24. The method of claim 21 , wherein the step of inserting new samples comprises creating new samples using standard curve-fitting techniques.

25. The method of claim 21 , wherein the plurality of input samples is converted into the plurality of intermediate samples using interpolation.

26. The method of claim 21 , wherein the samples are transmitted in packets.

Assignees

• Visteon Global Tech Inc

Inventors

• Whikehart J William
• Stewart David P
• Lavacek Dave

Classifications

• H03M7/46

  Conversion to or from run-length codes, i.e. by representing the number of consecutive digits, or groups of digits, of the same kind by a code word and a digit indicative of that kind · CPC title

• G11B20/10527

  Audio or video recording; Data buffering arrangements (G11B20/12 - G11B20/18 take precedence) · CPC title

• H03H17/0685

  the ratio being rational · CPC title

• G10L19/008

  Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing · CPC title

• H03M5/00 Primary

  Conversion of the form of the representation of individual digits · CPC title