Other

Tellabs Operations, Inc.

Dsp Software Engineering, Inc.

Douglas E Kolb

Jayesh S Patel

A method and apparatus for reducing the complexity of linear prediction analysis-by synthesis (LPAS) speech coders. The speech coder includes a multi-tap pitch predictor having various parameters and utilizing an adaptive codebook subdivided into at least a first vector codebook and a second vector codebook. The pitch predictor removes certain redundancies in a subject speech signal and vector quantizes the pitch predictor parameters.

LPAS speech coder using vector quantized, multi-codebook, multi-tap pitch predictor

A method and apparatus for reducing the complexity of linear prediction analysis-by-synthesis (LPAS) speech coders. The speech coder includes a multi-tap pitch predictor having various parameters and utilizing an adaptive codebook subdivided into at least a first vector codebook and a second vector codebook. The pitch predictor removes certain redundancies in a subject speech signal and vector quantizes the pitch predictor parameters. Further included is a source excitation (fixed) codebook that indicates pulses in the subject speech signal by deriving corresponding vector values. Serial optimization of the adaptive codebook first and then the fixed codebook produces a low complexity LPAS speech coder of the present invention.

LPAS speech coder using vector quantized, multi-codebook, multi-tap pitch predictor and optimized ternary source excitation codebook derivation

A method and apparatus for reducing the complexity of linear prediction analysis-by-synthesis (LPAS) speech coders. The method and apparatus include product code vector quantization (PCVQ) of multi-tap pitch predictor coefficients, which reduces the search and quantization complexity of an adaptive codebook. The pitch predictor vector quantizes the predictor parameters using at least two codebooks, which are effectively subcodebooks of the pitch predictor adaptive codebook. Further included is a procedure for generating and selecting code vectors consisting of ternary (1,0,&minus;1) values, for optimizing a fixed codebook. The fixed codebook makes a single pass derivation of pulse position in the excitation signal. Serial optimization of the adaptive codebook first and then the fixed codebook, produces a low complexity LPAS speech coder of the present invention.

A method and apparatus for reducing the complexity of linear prediction analysis-by-synthesis (LPAS) speech coders. The method and apparatus include product code vector quantization (PCVQ) of multi-tap pitch predictor coefficients, which reduces the search and quantization complexity of an adaptive codebook. Further included is a procedure for generating and selecting code vectors consisting of ternary (1,0,-1) values, for optimizing a fixed codebook. Serial optimization of the adaptive codebook first and then the fixed codebook, produces a low complexity LPAS speech coder of the present invention.

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Bedford, MA, United States of America

Douglas E Kolb