Post-filter common-gain determination

Patent metadata

Field	Value
Publication number	US-9553557-B2
Application number	US-201514854268-A
Country	US
Kind code	B2
Filing date	Sep 15, 2015
Priority date	Oct 24, 2011
Publication date	Jan 24, 2017
Grant date	Jan 24, 2017

Abstract

An apparatus for processing an input sound signal, the apparatus including: gain circuitry configured to control a gain based on a plurality of respective sub-signals of the input sound signal; and an amplification apparatus configured to adjust the amplification of all the plurality of amplitudes based on the common gain.

First claim

What is claimed is:

1. An apparatus, comprising:
a frequency analysis unit configured to decompose a sound signal into a plurality of sub-signals each associated with a specific frequency band of the sound signal;
amplitude detection circuits configured to produce provisional amplitudes for each of the sub-signals;
gain circuitry configured to determine a common gain based on the provisional amplitudes; and
an amplification module configured to generate a plurality of adjusted amplitudes by adjusting the amplification of all of the provisional amplitudes based on the common gain.

2. The apparatus of claim 1 , wherein the gain circuitry is configured to:
generate, in accordance with a plurality of gain rules each selected for one of the frequency bands, provisional gains for each of the provisional amplitudes; and
determine the common gain based on the provisional gains.

3. The apparatus of claim 2 , wherein to determine the common gain based on the provisional gains, the gain circuitry is configured to determine at least one of a minimum of the provisional gains, a median of the provisional gains, or a weighted mean of the provisional gains.

4. The apparatus of claim 1 , wherein the gain circuitry comprises:
a level combine circuit configured to analyze the provisional amplitudes and generate a level signal; and
a gain rule circuit configured to generate the common gain based upon the level signal.

5. The apparatus of claim 4 , wherein the level combine circuit is configured to:
calculate a maximum of the provisional amplitudes as the level signal.

6. The apparatus of claim 4 , wherein the level combine circuit is configured to:
calculate a median of the provisional amplitudes as the level signal.

7. The apparatus of claim 4 , wherein the level combine circuit is configured to:
calculate a weighted mean of the provisional amplitudes as the level signal.

8. The apparatus of claim 4 , wherein the gain circuitry further comprises:
timing detection circuits configured to determine timing signals according to each of the sub-signals.

9. The apparatus of claim 8 , further comprising:
a pulse generator configured to generate stimulation pulse data based upon the adjusted amplitudes and according to the timing signals.

10. The apparatus of claim 1 , further comprising:
a plurality of translation units configured to apply loudness growth functions to the plurality of adjusted amplitudes.

11. The apparatus of claim 10 , wherein the loudness growth functions have substantially the same saturation levels, and wherein the gain circuitry further comprises static compression circuitry that incorporates an infinite compression region, and a corresponding maximum output level that is substantially equal to the saturation levels of the loudness growth functions.

12. The apparatus of claim 1 , wherein the amplification module includes:
a bank of amplifiers configured to adjust the provisional amplitudes based upon the common gain so as to generate the plurality of adjusted amplitudes; and
a bank of translation units configured to apply loudness growth functions to the plurality of adjusted amplitudes.

13. A method comprising:
generating provisional amplitude envelopes for a plurality of sub-signals that each comprise a frequency component of an input sound signal;
generating, based on at least one gain rule, a common gain for application to each of the provisional amplitude envelopes; and
applying the common gain to all of the provisional amplitude envelopes to produce a plurality of adjusted amplitude envelopes.

14. The method of claim 13 , wherein generating the common gain based on the at least one gain rule comprises:
applying gain rules to each of the provisional amplitude envelopes to generate a plurality of provisional gains; and
determining the common gain based on the provisional gains.

15. The method of claim 14 , wherein determining the common gain based on the provisional gains further includes at least one: selecting a minimum of the provisional gains as the common gain, calculating a median of the provisional gains as the common gain, or calculating a mean of weighted provisional gains.

16. The method of claim 13 , wherein generating the common gain based on the based on at least one gain rule comprises:
generating a level signal based on the provisional amplitude envelopes; and
generating the common gain based upon the level signal.

17. The method of claim 16 , wherein generating the level signal comprises:
calculating a maximum of the provisional amplitude envelopes as the level signal.

18. The method of claim 16 , wherein generating the level signal comprises:
calculating a median of the provisional amplitude envelopes as the level signal.

19. The method of claim 16 , wherein generating the level signal comprises:
applying weights to the provisional amplitude envelopes to generate weighted amplitude envelopes; and
calculating a mean of the weighted provisional amplitude envelopes as the level signal.

20. The method of claim 16 , wherein the gain circuitry further comprises:
determining timing signals according to each of the sub-signals.

21. The method of claim 20 , further comprising:
generating stimulation pulse data based upon the adjusted amplitude envelopes and according to the timing signals.

22. The method of claim 13 , further comprising:
applying loudness growth functions to the plurality of adjusted amplitudes amplitude envelopes.

23. The method of claim 13 , further comprising:
prior to generating the provisional amplitude envelopes, performing a frequency analysis to decompose the sound signal into the plurality of sub-signals.

Assignees

• Swanson Brett Anthony
• Khing Phyu Phyu
• Cochlear Ltd

Inventors

• Swanson Brett Anthony
• Khing Phyu Phyu

Classifications

• H04R25/505

  using digital signal processing · CPC title

• G10L21/0316

  by changing the amplitude · CPC title

• G10L21/034

  Automatic adjustment · CPC title

• H03G7/002 Primary

  in untuned or low-frequency amplifiers, e.g. audio amplifiers (H03G7/007, H03G7/001, H03G7/008, H03G7/02, H03G7/06 take precedence) · CPC title

• H04R25/00

  Electric hearing aids · CPC title