Apparatus and method for encoding/decoding a speech signal using adaptively changing codebook vectors

Claim 2

A speech signal encoding method comprising the steps of: encoding a voiced portion of an input speech signal using a sinusoidal analysis technique; and encoding an unvoiced portion of said input speech signal using a code excitation linear prediction (CELP) technique, including dividing said input speech signal on a time axis into units of blocks; and encoding said divided input speech signal by vector quantization using a time-domain closed-loop search of an optimum vector based on an analysis-by-synthesis method, said optimum vector being a vector that minimizes an error between said input speech signal and an encoded speech signal, wherein said vector quantization of said divided input speech signal uses a codebook memory containing a first set of codebook vectors generated by clipping a Gaussian noise at a plurality of predetermined threshold values and a second set of codebook vectors generated by adaptively changing said first set of codebook vectors using said first set of codebook vectors as initial values.

Claim 3

The speech signal encoding method as claimed in claim 1, wherein said codebook memory used for said vector quantization includes a codebook vector having all zero elements.

Claim 4

A speech encoding apparatus for encoding an input speech signal divided on a time axis into units of blocks, the apparatus comprising: first encoding means for encoding a voiced portion of an input speech signal using a sinusoidal analysis technique; and second encoding means for encoding an unvoiced portion of said input speech signal using a code excitation linear prediction (CELP) technique, wherein said second encoding means performs vector quantization of results of a time-domain closed-loop search of an optimum vector using an analysis-by-synthesis method, and said second encoding means includes a codebook memory containing codebook vectors for performing said vector quantization, said codebook vectors including a first set of codebook vectors generated by clipping a Gaussian noise at a plurality of predetermined threshold values and a second set of codebook vectors generated by adaptively changing said first set of vectors using said first set of codebook vectors as initial values.

Claim 5

A speech encoding apparatus for encoding an input speech signal divided on a time axis into units of blocks, the apparatus comprising: first encoding means for encoding a voiced portion of an input speech signal using a sinusoidal analysis technique; and second encoding means for encoding an unvoiced portion of said input speech signal using a code excitation linear prediction (CELP) technique, wherein said second encoding means performs vector quantization of results of a time-domain closed-loop search of an optimum vector using an analysis-by-synthesis method, and said second encoding means includes a codebook memory containing codebook vectors for performing said vector quantization, said codebook vectors including a first set of codebook vectors generated by clipping a Gaussian noise at a plurality of predetermined threshold values and a second set of codebook vectors generated by adaptively changing said first set of vectors using said first set of codebook vectors as initial values.

Claim 6

A portable communication apparatus comprising: amplifier means for amplifying an input speech signal; A/D conversion means for performing analog to digital conversion of an amplified input speech signal from said amplifier means; speech encoding means for speech-encoding an output of said A/D conversion means, including a first encoding section for encoding a voiced portion of an input speech signal using a sinusoidal analysis technique; and a second encoding section for encoding an unvoiced portion of said input speech signal using a code excitation linear prediction (CELP) technique; transmission channel encoding means for channel-coding an output of said speech encoding means; modulation means for modulating a signal from said transmission channel encoding means; D/A conversion means for digital to analog conversion of a signal from said modulation means; and RF amplifier means for amplifying a signal from said D/A conversion means and supplying an output signal to an antenna, wherein said second encoding section includes means for performing vector quantization using a time-domain closed-loop search of an optimum vector based on an analysis-by-synthesis method, said optimum vector being a vector that minimizes an error between said input speech signal and an encoded speech signal and a codebook memory containing codebook vectors for performing said vector quantization, said codebook vectors including a first set of codebook vectors generated by clipping a Gaussian noise at a plurality of threshold values and a second set of codebook vectors generated by adaptively changing said first set of codebook vectors using said first set of codebook vectors as initial values.

Claim 7

A portable communication apparatus comprising: amplifier means for amplifying an input speech signal; A/D conversion means for performing analog to digital conversion of an amplified input speech signal from said amplifier means; speech encoding means for speech-encoding an output of said A/D conversion means, including a first encoding section for encoding a voiced portion of an input speech signal using a sinusoidal analysis technique; and a second encoding section for encoding an unvoiced portion of said input speech signal using a code excitation linear prediction (CELP) technique; transmission channel encoding means for channel-coding an output of said speech encoding means; modulation means for modulating a signal from said transmission channel encoding means; D/A conversion means for digital to analog conversion of a signal from said modulation means; and RF amplifier means for amplifying a signal from said D/A conversion means and supplying an output signal to an antenna, wherein said second encoding section includes means for performing vector quantization using a time-domain closed-loop search of an optimum vector based on an analysis-by-synthesis method, said optimum vector being a vector that minimizes an error between said input speech signal and an encoded speech signal and a codebook memory containing codebook vectors for performing said vector quantization, said codebook vectors including a first set of codebook vectors generated by clipping a Gaussian noise at a plurality of threshold values and a second set of codebook vectors generated by adaptively changing said first set of codebook vectors using said first set of codebook vectors as initial values.

Claim 8

A portable communication terminal apparatus comprising: RF amplifier means for amplifying an input speech signal; A/D conversion means for analog to digital conversion of an amplified input speech signal from said RF amplifier means; demodulation means for demodulating an output from said A/D conversion means; transmission channel decoding means for channel-decoding an output from said demodulation means; speech decoding means for speech-decoding an output of said transmission channel decoding means, said speech decoding means decoding a signal encoded by a first encoding section, which encodes a voiced portion of an input speech signal using a sinusoidal analysis technique, and a second encoding section, which encodes an unvoiced portion of said input speech signal using a code excitation linear prediction (CELP) technique; D/A conversion means for digital to analog conversion of a decoded signal from said speech decoding means; and amplifier means for amplifying an output signal from said D/A conversion means and supplying the amplified signal to a speaker, wherein said second encoding section performs vector quantization of results of a time-domain closed-loop search of an optimum vector using an analysis-by-synthesis method and a codebook memory containing a first set of codebook vectors generated by clipping a Gaussian noise at a plurality of threshold values and a second set of codebook vectors generated by adaptively changing said first set of codebook vectors using said first set of codebook vectors as initial values.

Claim 9

A portable communication terminal apparatus comprising: RF amplifier means for amplifying an input speech signal; A/D conversion means for analog to digital conversion of an amplified input speech signal from said RF amplifier means; demodulation means for demodulating an output from said A/D conversion means; transmission channel decoding means for channel-decoding an output from said demodulation means; speech decoding means for speech-decoding an output of said transmission channel decoding means, said speech decoding means decoding a signal encoded by a first encoding section, which encodes a voiced portion of an input speech signal using a sinusoidal analysis technique, and a second encoding section, which encodes an unvoiced portion of said input speech signal using a code excitation linear prediction (CELP) technique; D/A conversion means for digital to analog conversion of a decoded signal from said speech decoding means; and amplifier means for amplifying an output signal from said D/A conversion means and supplying the amplified signal to a speaker, wherein said second encoding section performs vector quantization of results of a time-domain closed-loop search of an optimum vector using an analysis-by-synthesis method and a codebook memory containing a first set of codebook vectors generated by clipping a Gaussian noise at a plurality of threshold values and a second set of codebook vectors generated by adaptively changing said first set of codebook vectors using said first set of codebook vectors as initial values.