Abstract: A signal separation device for acquiring a source signal from a mixed signal observed by a plurality of sensors includes: a database that stores feature information of a clean signal; separation matrix calculation means for repeatedly performing processes of, based on a separated signal obtained by multiplication of a mixed signal converted into a time-frequency representation by a separation matrix and on the feature information stored in the database, calculating a parameter to be used for an objective function for optimizing the separation matrix, and calculating a separation matrix for minimizing the objective function using the parameter; and output means for outputting a separated signal calculated using the optimized separation matrix obtained by the separation matrix calculation means.

Abstract: An encoding method includes dividing a to-be-encoded time-domain signal into a low band signal and a high band signal, performing encoding on the low band signal to obtain a low frequency encoding parameter, performing encoding on the high band signal to obtain a high frequency encoding parameter, obtaining a synthesized high band signal, performing short-time post-filtering processing on the synthesized high band signal to obtain a short-time filtering signal, and calculating a high frequency gain based on the high band signal and the short-time filtering signal.

Abstract: An encoding method, a decoding method, an encoding apparatus, a decoding apparatus, a transmitter, a receiver, and a communications system, where the encoding method includes dividing a to-be-encoded time-domain signal into a low band signal and a high band signal, performing encoding on the low band signal to obtain a low frequency encoding parameter, performing encoding on the high band signal to obtain a high frequency encoding parameter, obtaining a synthesized high band signal; performing short-time post-filtering processing on the synthesized high band signal to obtain a short-time filtering signal, and calculating a high frequency gain based on the high band signal and the short-time filtering signal.

Abstract: A method and apparatus for searching fixed codebook are provided. The method includes: obtaining a basic codebook which comprises position information of N pulses on M tracks, wherein N and M are positive integers; choosing n pulses as search pulses, wherein the n pulses are parts of the N pulses and n is a positive integer smaller than N; and replacing position information of the n search pulses respectively with other position information on the tracks to obtain a searched codebook; executing the search process for K times, wherein K is a positive integer larger than or equal to 2, at least two or more search pulses are chosen in one of the K search processes , and the chosen search pulses vary in each of the K search processes; and obtaining an optimal codebook from the basic codebook and the searched codebook according to a preset criterion.

Abstract: There is provided a method of post-processing a speech signal. The method comprises applying a time-domain post-processing to the speech signal, using LPC coefficients, for a low-band frequency range and applying a frequency-domain post-processing to the speech signal, using MDCT coefficients, for the high-band frequency range. Applying the frequency-domain post-processing includes decoding an encoded speech signal to obtain MDCT coefficients representative of the speech signal divided into a plurality of sub-bands, generating an envelope for each sub-band of the plurality of sub-bands as an average magnitude of the MDCT coefficients of the sub-band, generating an envelope modification factor for each sub-band of the plurality of sub-band using the MDCT coefficients of the sub-band, modifying the envelope by the envelope modification factor for each sub-band of the plurality of sub-bands to provide a modified envelope, and generating the post-processed speech signal using the modified envelope.

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: Provided is an adaptive sound source vector quantization device which can always perform a pitch cycle search with a resolution appropriate for any section of the pitch cycle search range of a second sub-frame when a pitch cycle search range of the second sub-frame changes in accordance with a pitch cycle of a first sub-frame. The device includes a first pitch cycle instruction unit (111), a search range calculation unit (112), and a second pitch cycle instruction unit (113). The first pitch cycle instruction unit (111) successively instructs pitch cycle search candidates in a predetermined search range having a search resolution which transits over a predetermined pitch cycle candidate for the first sub-frame. The search range calculation unit (112) calculates a predetermined range before and after the pitch cycle of the first sub-frame as the pitch cycle search range for the second sub-frame, if the predetermined range includes the predetermined pitch cycle search candidate.

Abstract: A method comprises identifying a component k of a codevector from a codebook C having one or more codevectors, the component k introducing highest variance for an input vector; allowing ordering of codevectors in the codebook C; and searching for a best match vector for the input vector using ordered codevectors.

Abstract: A method and apparatus for searching fixed codebook are provided. The method includes: obtaining a basic codebook which comprises position information of N pulses on M tracks, wherein N and M are positive integers; choosing n pulses as search pulses, wherein the n pulses are parts of the N pulses and n is a positive integer smaller than N; and replacing position information of the n search pulses respectively with other position information on the tracks to obtain a searched codebook; executing the search process for K times, wherein K is a positive integer larger than or equal to 2, at least two or more search pulses are chosen in one of the K search processes , and the chosen search pulses vary in each of the K search processes; and obtaining an optimal codebook from the basic codebook and the searched codebook according to a preset criterion.