Systems and methods for detecting overflow

Patent metadata

Field	Value
Publication number	US-9449607-B2
Application number	US-201213666870-A
Country	US
Kind code	B2
Filing date	Nov 1, 2012
Priority date	Jan 6, 2012
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A method for detecting overflow on an electronic device is described. The method includes determining a linear predictive coding synthesis filter gain. The method further includes determining whether overflow is detected based on the linear predictive coding synthesis filter gain and a fixed codebook gain. The method further includes determining a scaling factor if overflow is detected.

First claim

What is claimed is:

1. A method for detecting overflow on an electronic device, comprising:
determining, by an audio codec, a linear predictive coding synthesis filter gain;
determining, by the audio codec, whether overflow is detected based on the linear predictive coding synthesis filter gain and comparing a fixed codebook gain to a fixed codebook gain threshold; and
determining, by the audio codec, a scaling factor in a case that overflow is detected.

2. The method of claim 1 , wherein the scaling factor is determined such that an output of a linear predictive coding synthesis filter does not exceed a maximum dynamic range.

3. The method of claim 1 , further comprising scaling a signal based on the scaling factor if overflow is detected.

4. The method of claim 1 , wherein overflow is detected in a case that the linear predictive coding synthesis filter gain is greater than or equal to a synthesis filter gain threshold and the fixed codebook gain is greater than or equal to the fixed codebook gain threshold.

5. The method of claim 1 , wherein determining the linear predictive coding synthesis filter gain comprises:
determining an impulse response corresponding to a linear predictive coding synthesis filter; and
determining an energy of the impulse response.

6. The method of claim 1 , wherein the method is performed by at least one of a group consisting of a decoder and an encoder.

7. The method of claim 1 , wherein the electronic device is a wireless communication device.

8. The method of claim 1 , wherein determining whether overflow is detected is further based on an adaptive codebook gain.

9. The method of claim 1 , wherein overflow is detected in a case that the linear predictive coding synthesis filter gain is greater than or equal to a synthesis filter gain threshold, the fixed codebook gain is greater than or equal to a fixed codebook gain threshold, and an adaptive codebook gain is greater than or equal to an adaptive codebook gain threshold.

10. The method of claim 1 , wherein in the case that overflow is detected, the scaling factor is not applied to a signal that is carried forward to a subsequent frame or subframe.

11. The method of claim 1 , wherein determining whether overflow is detected comprises determining whether a synthesis filter output would exceed a maximum allotted dynamic range if a synthesis filter input is not scaled down.

12. A decoder for detecting overflow, comprising:
synthesis filter gain determination circuitry configured to determine a linear predictive coding synthesis filter gain;
an overflow detector coupled to the synthesis filter gain determination circuitry, wherein the overflow detector is configured to determine whether overflow is detected based on the linear predictive coding synthesis filter gain and a comparison of a fixed codebook gain to a fixed codebook gain threshold; and
scaling factor determination circuitry coupled to the overflow detector, wherein the scaling factor determination circuitry is configured to determine a scaling factor in a case that overflow is detected.

13. The decoder of claim 12 , wherein the scaling factor is determined such that an output of a linear predictive coding synthesis filter does not exceed a maximum dynamic range.

14. The decoder of claim 12 , further comprising a multiplier coupled to the scaling factor determination circuitry, wherein the multiplier scales a signal based on the scaling factor if overflow is detected.

15. The decoder of claim 12 , wherein the overflow detector is configured to detect overflow in a case that the linear predictive coding synthesis filter gain is greater than or equal to a synthesis filter gain threshold and the fixed codebook gain is greater than or equal to the fixed codebook gain threshold.

16. The decoder of claim 12 , wherein the decoder is configured to determine the linear predictive coding synthesis filter gain by:
determining an impulse response corresponding to a linear predictive coding synthesis filter; and
determining an energy of the impulse response.

17. The decoder of claim 12 , wherein the overflow detector is configured to determine whether overflow is detected based on an adaptive codebook gain.

18. The decoder of claim 12 , wherein the overflow detector is configured to detect overflow in a case that the linear predictive coding synthesis filter gain is greater than or equal to a synthesis filter gain threshold, the fixed codebook gain is greater than or equal to a fixed codebook gain threshold, and an adaptive codebook gain is greater than or equal to an adaptive codebook gain threshold.

19. The decoder of claim 12 , wherein in the case that overflow is detected, the decoder is configured to not apply the scaling factor to a signal that is carried forward to a subsequent frame or subframe.

20. The decoder of claim 12 , wherein the overflow detector is configured to determine whether overflow is detected by determining whether a synthesis filter output would exceed a maximum allotted dynamic range if a synthesis filter input is not scaled down.

21. A non-transitory tangible computer-readable medium having instructions thereon, the instructions comprising:
code for causing an audio codec to determine a linear predictive coding synthesis filter gain;
code for causing the audio codec to determine whether overflow is detected based on the linear predictive coding synthesis filter gain and comparing a fixed codebook gain to a fixed codebook gain threshold; and
code for causing the audio codec to determine a scaling factor in a case that overflow is detected.

22. The non-transitory tangible computer-readable medium of claim 21 , wherein the scaling factor is determined such that an output of a linear predictive coding synthesis filter does not exceed a maximum dynamic range.

23. The non-transitory tangible computer-readable medium of claim 21 , further comprising code for causing the audio codec to scale a signal based on the scaling factor if overflow is detected.

24. The non-transitory tangible computer-readable medium of claim 21 , wherein overflow is detected in a case that the linear predictive coding synthesis filter gain is greater than or equal to a synthesis filter gain threshold and the fixed codebook gain is greater than or equal to the fixed codebook gain threshold.

25. The non-transitory tangible computer-readable medium of claim 21 , wherein detecting overflow is further based on an adaptive codebook gain.

26. A decoder for detecting overflow, comprising:
means for determining a linear predictive coding synthesis filter gain;
means for determining whether overflow is detected based on the linear predictive coding synthesis filter gain and comparing a fixed codebook gain to a fixed codebook gain threshold; and
means for determining a scaling factor in a case that overflow is detected.

27. The decoder of claim 26 , wherein the scaling factor is determined such that an output of a linear predictive coding synthesis filter does not exceed a maximum dynamic range.

28. The decoder of claim 26 , further comprising means for scaling a signal based on the scaling factor if overflow is detected.

29. The decoder of claim 26 , wherein overflow is detected in a case that the linear predictive coding synthesis filter gain is greater than or equal to a synthesis filter gain threshold and the fi

Assignees

• Qualcomm Inc

Inventors

• Rajendran Vivek
• Kandhadai Ananthapadmanabhan Arasanipalai

Classifications

• G10L19/083 Primary

  the excitation function being an excitation gain (G10L25/90 takes precedence) · CPC title

• G10L19/005

  Correction of errors induced by the transmission channel, if related to the coding algorithm · CPC title