Abstract: A vector quantization apparatus performs coding of a linear predictive coding coefficient by multi-stage vector quantization. A first codebook and a second codebook store code vectors, and a storing section stores scalars. A first quantizing section extracts a first code vector stored in the first codebook and performs first stage quantization for quantizing a target vector using the first code vector. A second quantizing section extracts a second code vector stored in the second codebook, calculates a third code vector by multiplying the second code vector and one of the scalars stored in the storing section, performs distance calculation using the target vector, the first code vector and the third code vector, and performs second stage quantization for quantizing the target vector using a result of the distance calculation. Each scalar stored in the storing section is associated with at least one of the vectors stored in the first codebook.

Abstract: A target vector is coded by multi-stage vector quantization. A first stage of the coding of the target vector uses a first code vector stored in a first codebook. A scalar associated with a code of each first code vector is stored. A third code vector is determined by multiplying a second code vector stored in a second codebook and the scalar together, performing distance calculation using the target vector, the first code vector and the third code vector, and performing a second stage of the coding of the target vector using a result of the distance calculation.

Abstract: A code excited linear prediction type speech coder, which includes a seed storage that stores seeds used as an initial state of oscillation, and an oscillator that generates different vector sequences in accordance with values of the seeds stored in the seed storage and outputs the vector sequences as excitation vectors. The speech coder also includes a linear predictive coding synthesis filter that receives, as input, the excitation vectors, which are the vector sequences generated in accordance with the values of the seeds, that synthesizes the excitation vectors, and that outputs a synthesized speech.

Abstract: A CELP speech decoder includes an adaptive codebook that generates an adaptive code vector and a random codebook that generates a random code vector. The random codebook includes an input vector provider that provides an input vector including at least one pulse, each pulse having a position and a polarity, a fixed waveform storage that stores at least one fixed waveform, and a selector that selects at least one of a first process and a second process based on a value of an adaptive codebook gain. The random codebook further includes a convolution section that generates the random code vector by convoluting the at least one fixed waveform with the input vector when the first process is selected. A synthesis filter outputs synthesized speech by performing linear prediction coefficient synthesis on a signal based on the adaptive code vector and the random code vector.

Abstract: Speech is coded using an orthogonal search by calculating a search reference value. An adaptive codevector representing a pitch component is generated. A random codevector representing a random component is also generated. The orthogonal search further includes generating a synthetic speech signal by a synthesis filter being excited by the adaptive codevector and the random codevector. A distortion between the input speech signal and the synthetic speech signal is calculated. One random codevector that minimizes the distortion is selected.

Abstract: A code excited linear prediction type speech coder, which includes a seed storage that stores seeds used as an initial state of oscillation, and an oscillator that generates different vector sequences in accordance with values of the seeds stored in the seed storage and outputs the vector sequences as excitation vectors. The speech coder also includes a linear predictive coding synthesis filter that receives, as input, the excitation vectors, which are the vector sequences generated in accordance with the values of the seeds, that synthesizes the excitation vectors, and that outputs a synthesized speech.

Abstract: A CELP speech decoder includes an adaptive codebook that generates an adaptive code vector and a random codebook that generates a random code vector. The random codebook includes an input vector provider that provides an input vector including at least one pulse, each pulse having a position and a polarity, a fixed waveform storage that stores at least one fixed waveform, and a selector that selects at least one of a first process and a second process based on a value of an adaptive codebook gain. The random codebook further includes a convolution section that generates the random code vector by convoluting the at least one fixed waveform with the input vector when the first process is selected. A synthesis filter outputs synthesized speech by performing linear prediction coefficient synthesis on a signal based on the adaptive code vector and the random code vector.

Abstract: A vector quantization apparatus performs coding of a linear predictive coding coefficient by multi-stage vector quantization. A first codebook and a second codebook store code vectors, and a storing section stores scalars. A first quantizing section extracts a first code vector stored in the first codebook and performs first stage quantization for quantizing a target vector using the first code vector. A second quantizing section extracts a second code vector stored in the second codebook, calculates a third code vector by multiplying the second code vector and one of the scalars stored in the storing section, performs distance calculation using the target vector, the first code vector and the third code vector, and performs second stage quantization for quantizing the target vector using a result of the distance calculation. Each scalar stored in the storing section is associated with at least one of the vectors stored in the first codebook.

Abstract: A code excited linear prediction speech decoder includes an adaptive codebook configured to generate an adaptive code vector. The decoder also includes a random codebook configured to generate a random code vector. The decoder also includes a synthesis filter that receives a signal based on said adaptive code vector and said random code vector, and that is configured to perform linear prediction coefficient synthesis on said signal. The random codebook includes a pulse vector providing system configured to provide a pulse vector having a signed unit pulse. The random codebook also includes a comparing system configured to compare a value of adaptive codebook gain with a preset threshold value. The random codebook further includes a selecting system configured to select a dispersion pattern from a plurality of dispersion patterns stored in a memory in accordance with a result of said comparison.

Abstract: At the speech encoding end, upon generation of an fixed excitation vector, the shape of an excitation vector output from pulse excitation codebook 301 is identified in pulse excitation vector shape identifier 302, a dispersion vector used for excitation vectors of the shape is output from dispersion vector storage 304, and, in dispersion vector convolution processor 303, dispersion vector convolution processing of the excitation vector is performed. In particular, when a pulse excitation vector having a specific shape of high frequency of use is output from pulse excitation codebook 301, pulse excitation vector shape identifier 302 controls dispersion vector storage 304 in such a way that an additional dispersion vector prepared dedicated to the pulse excitation vector is output. By this means, it is possible to provide a technology that improves the quality of decoded speech and that decodes speech more natural and audible to the user.

Abstract: A dispersed vector generator used for a speech encoder or a speech decoder includes a pulse vector provider that provides a pulse vector having a signed unit pulse on one element of a vector axis. A dispersion pattern determiner determines a dispersion pattern of a set of waveforms defined before a start of encoding or decoding. A dispersed vector generator convolutes the pulse vector and the determined dispersion pattern to generate a dispersed vector. A length of the waveforms is shorter than a length of a sub-frame.

Abstract: An apparatus sets a pitch cycle search object in pitch cycle search processing for searching for a pitch cycle included in a linear predictive residual on a per subframe basis. A pitch cycle indicator of the apparatus sequentially output spitch cycle candidates within a predetermined pitch cycle search range at integral accuracy. A memory stores an integral component of a pitch cycle selected in pitch cycle search processing of a previous subframe. An adaptive sound source vector generator sets, as the pitch cycle search object in pitch cycle search processing in a processing subframe section, a group of candidates comprising a group of integral-accuracy pitch cycle candidates output from the pitch cycle indicator and a group of fractional-accuracy pitch cycle search candidates that cover a pitch cycle near an integral component of the pitch cycle read from the previous subframe integral pitch cycle memory using fractional accuracy.

Abstract: Speech is coded using an orthogonal search by calculating a search reference value. An adaptive codevector representing a pitch component is generated. A random codevector representing a random component is also generated. The orthogonal search further includes generating a synthetic speech signal by a synthesis filter being excited by the adaptive codevector and the random codevector. A distortion between the input speech signal and the synthetic speech signal is calculated. One random codevector that minimizes the distortion is selected.

Abstract: A target vector is coded by multi-stage vector quantization. A first stage of the coding of the target vector uses a first code vector stored in a first codebook. A scalar associated with a code of each first code vector is stored. A third code vector is determined by multiplying a second code vector stored in a second codebook and the scalar together, performing distance calculation using the target vector, the first code vector and the third code vector, and performing a second stage of the coding of the target vector using a result of the distance calculation.

Abstract: A target vector is coded by multi-stage vector quantization. A first stage of the coding of the target vector is performed using a first code vector stored in a first codebook. A scalar associated with a code of each first code vector is stored in an amplifier storing section. A third code vector is determined by multiplying a second code vector stored in a second codebook with the scalar, calculating a distance using the target vector, the first code vector and the third code vector, and performing a second stage of the coding of the target vector using a result of the distance calculation.

Abstract: A code excited linear prediction speech decoder is provided. An adaptive codebook generates an adaptive code vector. A random codebook generates a random code vector. A synthesis filter receives a signal based on the adaptive code vector and the random code vector, and performs linear prediction coefficient synthesis on the signal. The random codebook includes a pulse vector provider that provides a pulse vector having a signed unit pulse, a comparator that compares a value of adaptive codebook gain with a preset threshold value, a selector that selects a dispersion pattern from a plurality of dispersion patterns stored in a memory in accordance with a result of the comparison, and a generator that generates the dispersed vector by convoluting the pulse vector and the selected dispersion pattern.

Abstract: A first determiner 121 tentatively determines whether the current processing unit represents a stationary noise period, based on stationary properties of a decoded signal. Based on the tentative determination result and a determination result of the periodicity of the decoded signal, a second determiner 124 determines whether the current processing unit represents a stationary noise period, thereby distinguishing a decoded signal including a stationary speech signal such as a stationary vowel from stationary noise and correctly identifying the stationary noise period.

Abstract: A speech coder includes a seed storage that stores a plurality of seeds used as an initial state of oscillation. An oscillator generates different vector sequences in accordance with values of the seeds stored in the seed storage and outputs the vector sequences as excitation vectors. A linear predictive coding synthesis filter receives, as input, the excitation vectors synthesizes the excitation vectors, and outputs a synthesized speech.

Abstract: A speech encoder includes an adaptive codebook that generates an adaptive codevector representing a pitch component, a random codebook that generates a random codevector representing a random component, and a synthesis filter that generates a synthetic speech signal by being excited by the adaptive codevector and the random codevector. The random codebook includes an input vector provider configured to provide an input vector, and an excitation vector generator configured to generate an excitation vector as the random codevector by dispersing the input vector by using a fixed pattern. A length of the fixed pattern is shorter than a length of a sub-frame.

Abstract: First codebook and second codebook respectively have two subcodebooks, and in respective codebooks, addition sections obtain respective excitation vectors by adding sub-excitation vectors fetched from respective two subcodebooks. Addition section obtains an excitation sample by adding those excitation vectors. According to the aforementioned constitution, it is possible to store sub-excitation vectors with different characteristics in respective sub-codebooks. Therefore, it is possible to correspond to input signals with various characteristics, and achieve excellent sound qualities at the time of decoding.