Adaptive tilt compensation for synthesized speech

• US 20080294429A1
• Filed: 06/27/2008
• Published: 11/27/2008
• Est. Priority Date: 09/18/1998
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Mindspeed Technologies Inc. (MACOM Technology Solutions Holdings, Inc.), Conexant Systems Incorporated (Synaptics Incorporated)
• Inventors: Gao, Yang, Su, Huan-Yu
• Granted Patent: US 9,401,156 B2
• Time in Patent Office: Days
• US Class Current: 704/222
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G10L 19/09 Long term prediction, i.e. removing periodical redundancies, e.g. by using adaptive codebook or pitch predictor
• CPC Class Codes: G10L 19/12 the excitation function being a code excitation, e.g. in code excited linear prediction [CELP] vocoders
• CPC Class Codes: G10L 19/18 Vocoders using multiple modes
• CPC Class Codes: G10L 19/20 using sound class specific coding, hybrid encoders or object based coding
• CPC Class Codes: G10L 2019/0002 Codebook adaptations
• CPC Class Codes: G10L 2019/0016 Codebook for LPC parameters
• CPC Class Codes: G10L 25/90 Pitch determination of speech signals

Abstract

There is provided a method of using an adaptive tilt compensation by a speech decoder. The method comprises receiving a bit stream including a plurality of parameters representative of a speech signal; identifying an adaptive code vector and a fixed code vector using the plurality of parameters; scaling the adaptive code vector and the fixed code vector to generate a scaled adaptive code vector and a scaled fixed code vector; summing the scaled adaptive code vector and the scaled fixed code vector to generate a synthesized output; calculating a first reflection coefficient based on the plurality of parameters representative of the speech signal; multiplying the first reflection coefficient by a factor to generate a tilt factor; and applying the tilt factor to the synthesized output based on an encoding bit rate.

Claims

1-20. -20. (canceled)

21. A method of using an adaptive tilt compensation by a speech decoder, the method comprising:

receiving a bit stream including a plurality of parameters representative of a speech signal;

identifying an adaptive code vector and a fixed code vector using the plurality of parameters;

scaling the adaptive code vector and the fixed code vector to generate a scaled adaptive code vector and a scaled fixed code vector;

summing the scaled adaptive code vector and the scaled fixed code vector to generate a synthesized output;

calculating a first reflection coefficient based on the plurality of parameters representative of the speech signal;

multiplying the first reflection coefficient by a factor to generate a tilt factor; and

applying the tilt factor to the synthesized output based on an encoding bit rate.

22. The method of claim 21 further comprising:

applying a synthesis filter to the synthesized output.

23. The method of claim 22, wherein applying the tilt factor occurs prior to applying the synthesis filter to the synthesized output.

24. The method of claim 21, wherein the speech decoder includes a first encoding bit rate and a second encoding bit rate, wherein the first encoding bit rate is higher than the second encoding bit rate, and wherein the method further comprises:

determining whether the encoding bit rate is the first encoding bit rate or the second encoding bit rate;

applying the tilt factor to the synthesized output if the encoding bit rate is the second encoding bit rate; and

deciding to not apply the tilt factor to the synthesized output if the encoding bit rate is the first encoding bit rate.

25. A speech decoder comprising:

a receiver configured to receive a bit stream including a plurality of parameters representative of a speech signal;

an adaptive codebook;

a fixed codebook;

wherein the speech decoder is configured to identify an adaptive code vector and a fixed code vector using the plurality of parameters from the adaptive codebook and the fixed codebook, respectively;

wherein the speech decoder is further configured to scale the adaptive code vector and the fixed code vector to generate a scaled adaptive code vector and a scaled fixed code vector;

wherein the speech decoder is further configured to sum the scaled adaptive code vector and the scaled fixed code vector to generate a synthesized output;

wherein the speech decoder is further configured to calculate a first reflection coefficient based on the plurality of parameters representative of the speech signal;

wherein the speech decoder is further configured to multiply the first reflection coefficient by a factor to generate a tilt factor; and

wherein the speech decoder is further configured to apply the tilt factor to the synthesized output based on an encoding bit rate.

26. The speech decoder of claim 25, wherein the speech decoder is further configured to apply a synthesis filter to the synthesized output.

27. The speech decoder of claim 26, wherein the speech decoder is further configured to apply the tilt factor before applying the synthesis filter to the synthesized output.

28. The speech decoder of claim 25, wherein the speech decoder includes a first encoding bit rate and a second encoding bit rate, wherein the first encoding bit rate is higher than the second encoding bit rate, and wherein the speech decoder is further configured to determine whether the encoding bit rate is the first encoding bit rate or the second encoding bit rate, apply the tilt factor to the synthesized output if the encoding bit rate is the second encoding bit rate, and decide to not apply the tilt factor to the synthesized output if the encoding bit rate is the first encoding bit rate.