Dynamic range control module, speech processing apparatus, and method for amplitude adjustment for a speech signal

• US 8,332,215 B2
• Filed: 10/31/2008
• Issued: 12/11/2012
• Est. Priority Date: 10/31/2008
• Status: Active Grant

• Current Assignee: Fortemedia, Inc.
• Original Assignee: Fortemedia, Inc.
• Inventors: Zhang, Ming, Pai, Wan-Chieh
• Primary Examiner(s): Chawan, Vijay B
• Application Number:
  US12/262,362
• Publication Number:
  US 20100114569A1
• Time in Patent Office: 1,502 Days
• Field of Search: 704/260, 704/258, 704/267, 704/225, 704/257, 704/268, 704/254, 704/253, 704/9, 455/72, 455/168.1
• US Class Current: 704/225
• CPC Class Codes: G10L 21/00 Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility G10L19/00 takes precedence
• CPC Class Codes: G10L 25/90 Pitch determination of speech signals

Abstract

The invention provides a dynamic range control module installed in a speech processing apparatus. In one embodiment, the dynamic range control module comprises a buffer, a voice activity detector, a peak calculation module, and an amplitude adjusting module. The buffer buffers a speech signal to obtain a delayed speech signal. The voice activity detector determines a syllable from the delayed speech signal. The peak calculation module calculates peak amplitude of the syllable. The amplitude adjusting module determines an attenuation factor corresponding to the syllable according to the peak amplitude in the syllable, and adjusts amplitude of the whole syllable with the same gain according to the attenuation factor to obtain an adjusted speech signal.

Claims

1. A speech processing apparatus, comprising:

a speech signal source, generating a speech signal;

a dynamic range control module, coupled to the speech signal source, determining a syllable from the speech signal, calculating a peak amplitude of the syllable, and adjusting amplitude of the whole syllable with a same gain according to the peak amplitude in the syllable to obtain an adjusted speech signal; and

a power amplifier, coupled to the dynamic range control module, amplifying the adjusted speech signal to obtain an amplified speech signal.

2. The speech processing apparatus as claimed in claim 1, wherein the dynamic range control module comprises:

a buffer, buffering the speech signal to obtain a delayed speech signal;

a voice activity detector, determining the syllable from the delayed speech signal;

a peak calculation module, calculating the peak amplitude of the syllable; and

an amplitude adjusting module, determining an attenuation factor corresponding to the syllable according to the peak amplitude, and adjusting the amplitude of the syllable according to the attenuation factor to obtain the adjusted speech signal.

3. The speech processing apparatus as claimed in claim 2, wherein the voice activity detector calculates the amplitude of the delayed speech signal, determines whether the amplitude exceeds a threshold level to identify a start edge of the syllable, and then determines whether the amplitude falls below the threshold level to identify an end edge of the syllable, thus determining a range of the syllable from the delayed speech signal.

4. The speech processing apparatus as claimed in claim 2, wherein the peak calculation module calculates a plurality of amplitude values of samples of the delayed speech signal within the range of the syllable, and then selects a maximum amplitude value from the amplitude values as the peak amplitude of the syllable.

5. The speech processing apparatus as claimed in claim 2, wherein the amplitude adjusting module determines a target amplitude region comprising the peak amplitude from a plurality of amplitude regions, determines an attenuation level corresponding to the target amplitude region as the attenuation factor, and then adjusts the amplitude of the syllable according to the attenuation factor.

6. The speech processing apparatus as claimed in claim 2, wherein the amplitude adjusting module adjusts the amplitude of the syllable according to the following algorithm:

7. The speech processing apparatus as claimed in claim 1, wherein the speech processing apparatus further comprises a speaker, broadcasting the amplified speech signal.

8. A dynamic range control module, installed in a speech processing apparatus, comprising:

a buffer, buffering a speech signal to obtain a delayed speech signal;

a voice activity detector, determining a syllable from the delayed speech signal;

a peak calculation module, calculating a peak amplitude of the syllable; and

an amplitude adjusting module, determining an attenuation factor corresponding to the syllable according to the peak amplitude in the syllable, and adjusting an amplitude of the whole syllable with a same gain according to the attenuation factor to obtain an adjusted speech signal.

9. The dynamic range control module as claimed in claim 8, wherein the speech processing apparatus comprises:

a speech signal source, generating the speech signal;

the dynamic range control module, coupled to the speech signal source, deriving the adjusted speech signal from the speech signal; and

a power amplifier, coupled to the dynamic range control module, amplifying the adjusted speech signal to obtain an amplified speech signal.

10. The dynamic range control module as claimed in claim 9, wherein the speech processing apparatus further comprises a speaker, broadcasting the amplified speech signal.

11. The dynamic range control module as claimed in claim 8, wherein the voice activity detector calculates the amplitude of the delayed speech signal, determines whether the amplitude exceeds a threshold level to identify a start edge of the syllable, and then determines whether the amplitude falls below the threshold level to identify an end edge of the syllable, thus determining a range of the syllable from the delayed speech signal.

12. The dynamic range control module as claimed in claim 8, wherein the peak calculation module calculates a plurality of amplitude values of samples of the delayed speech signal within the range of the syllable, and then selects a maximum amplitude value from the amplitude values as the peak amplitude of the syllable.

13. The dynamic range control module as claimed in claim 8, wherein the amplitude adjusting module determines a target amplitude region comprising the peak amplitude from a plurality of amplitude regions, determines an attenuation level corresponding to the target amplitude region as the attenuation factor, and then adjusts the amplitude of the syllable according to the attenuation factor.

14. The dynamic range control module as claimed in claim 8, wherein the amplitude adjusting module adjusts the amplitude of the syllable according to the following algorithm:

15. A method for amplitude adjustment for a speech signal, comprising:

buffering a speech signal to obtain a delayed speech signal;

determining a syllable from the delayed speech signal;

calculating a peak amplitude of the syllable;

determining an attenuation factor corresponding to the syllable according to the peak amplitude in the syllable; and

adjusting amplitude of the whole syllable with a same gain according to the attenuation factor to obtain an adjusted speech signal.

16. The method as claimed in claim 15, wherein the method further comprises:

amplifying the adjusted speech signal to obtain an amplified speech signal; and

broadcasting the amplified speech signal.

17. The method as claimed in claim 15, wherein determination of the syllable comprises:

calculating the amplitude of the delayed speech signal;

determining whether the amplitude exceeds a threshold level to identify a start edge of the syllable; and

determining whether the amplitude falls below the threshold level to identify an end edge of the syllable.

18. The method as claimed in claim 15, wherein calculation of the peak amplitude comprises:

calculating a plurality of amplitude values of samples of the delayed speech signal within the range of the syllable; and

selecting a maximum amplitude value from the amplitude values as the peak amplitude.

19. The method as claimed in claim 15, wherein determination of the attenuation factor comprises:

determining a target amplitude region comprising the peak amplitude from a plurality of amplitude regions; and

determining an attenuation level corresponding to the target amplitude region as the attenuation factor.

20. The method as claimed in claim 15, wherein adjustment of the amplitude of the syllable is according to the following algorithm: