In a CELP system, a coder and a decoder have identical codebooks, and the amount of data to be transmitted is compressed by transmission and reception of codebook indexes. Past excitation signals are stored in a memory and used as an adaptive codebook to improve the speech quality. The coder and the decoder each comprise memory means for storing index data for at least one frame, and means for generating an adaptive codebook afresh by initialization to zero for each frame when generating an exci...

A vector codebook with an ordered set of vector entries that satisfy a prearranged continuity requirement is used to encode signals. The continuity requirement specifies that consecutively considered vectors may not differ from each other by more than k elements, where k is less than the number of elements in the vectors. In one embodiment, two memories are maintained. One for determining the best codebook vector selection, and one for quantizing the input signal in accordance with the selected ...

Code-excited linear prediction speech encoders/decoders with excitation including an algebraic codebook contribution encoded with a single sign bit for each track of pulses by inferring pulse amplitude signs from the pulse position code ordering within a codeword.

An improved multi-codebook phase-in coding process for coding electronic data wherein for each received electronic input data, the coding process detects whether that input data exceeds a current coding maximum, then selecting a codebook coding method from one or more codebook coding methods in response to detecting whether that input data exceeds the current coding maximum, and then encoding that input data in accordance to the selected codebook coding method to generate a coded output data. A ...

A speech encoding comb codebook structure for providing good quality reproduced low bit-rate speech signals in a speech encoding system. The codebook structure requires minimal training, if any, and allows for reduced complexity and memory requirements. The codebook includes a first and at least one additional sub-codebooks, each having a plurality of code-vectors. The codebook may be randomly populated. All even elements may be set to zero in a first codebook, and all odd elements may be set to...

A speech compression system capable of encoding a speech signal into a bitstream for subsequent decoding to generate synthesized speech is disclosed. The speech compression system optimizes the bandwidth consumed by the bitstream by balancing the desired average bit rate with the perceptual quality of the reconstructed speech. The speech compression system comprises a full-rate codec, a half-rate codec, a quarter-rate codec and an eighth-rate codec. The codecs are selectively activated based on ...

A method for searching a codebook which predicts a residual element of an input voice signal includes combining each track of the input signal, forming track units including at least two tracks, and determining a pulse code for each track. The method further includes calculating energy for each track using an energy formula including a vector dot product, arranging or selecting codewords in a small track energy order, and searching or selecting an optimal pulse for a single- or double-pulse trac...

A method of compressing an image frame composed of an array of pixels in the form of digital signals comprises a two stage codebook search. In the first stage the pixelated image frame and the pixelated codebook patches are transformed to frequency domain coefficients and a pattern comparison is made between the coefficients of the image patch and the codebook patches to identify a short list of possible match codebook patches by discarding incorrectly matching patterns. In the second stage the ...

A speech compression system with a special fixed codebook structure and a new search routine is proposed for speech coding. The system is capable of encoding a speech signal into a bitstream for subsequent decoding to generate synthesized speech. The codebook structure uses a plurality of subcodebooks. Each subcodebook is designed to fit a specific group of speech signals. A better way is used to calculate a criterion value, minimizing an error signal in a minimization loop as part of the coding...

A fixed codebook searching apparatus which slightly suppresses an increase in the operation amount, even if the filter applied to the excitation pulse has the characteristic that it cannot be represented by a lower triangular matrix and realizes a quasi-optimal fixed codebook search. This fixed codebook searching apparatus is provided with an algebraic codebook (101) that generates a pulse excitation vector; a convolution operation section (151) that convolutes an impulse response of an auditory...