Code-excited linear prediction

About: Code-excited linear prediction is a research topic. Over the lifetime, 2025 publications have been published within this topic receiving 28633 citations. The topic is also known as: CELP.

Research on Order-Variable Code Exited Linear Prediction Speech Coding Method

Abstract: On the base of all-poles model, this paper provides order-variable all-poles model according to instability of track complexity and applies this model in code-excited linear predictive speech coding This method is simulated in Matlab and quality of synthesized speech is evaluated, order-variable model is founded to keep better speech quality on the base of decreasing coding rates

Variable dimensional algebraic CELP coding of prototype waveforms

Abstract: We propose a variable dimensional algebraic codebook structure in order to quantize the prototype waveforms efficiently. The proposed algorithm adjusts the interval of candidate pulse positions in a codevector according to the pitch period. The analysis-by-synthesis search procedure is computationally efficient due to the characteristics of the algebraic codebook structure. We also develop a method to perceptually improve the basis pulse of codevectors, which enhances the reconstructed speech quality with little increase in computational complexity. The improved prototype waveform interpolation coder adopting the proposed methods achieves a high quality of speech at 4 kbps.

Device for the execution of an algorithm (leroux-gueguen) for the coding of a signal by linear prediction

Abstract: The invention relates to an apparatus for using the Leroux-Gueguen algorithm for coding a signal by linear prediction. Apparatus applicable to the coding of a signal uses the Leroux-Gueguen algorithm for coding the signal by linear prediction. The apparatus receives at one input, correlation, multiplexers, two multipliers, two adders and a divider which, by successive iterations, calculate intermediate variables making it possible to pass from correlation coefficients Ri to PARCOR coefficients Ki.

Voice coder and decoder

Abstract: PURPOSE:To keep a narrow transmission band without deteriorating voice quality by assigning a shorter code to a code vector index of the code book of a code excitation linear prediction(CELP) coding system as the probability of generation of each code vector becomes higher. CONSTITUTION:When a conventional CELP system coder is applied, a coder 1, which has an original code book 5, is provided. Arbitrary voice signals are inputted to the coder 1 for a long time and outputted total number of vectors and the number of generation for every vector are obtained from the output codes by an all vector counter 2 and an each vector counter 3. From the total number of vectors and the number of generation for every vector, the probability of generation for every coded vector is computed. Then, the code book of each vector is obtained and a code word with the length of the book is assigned. Based on the probability of the generation of each vector, the code vector index is replaced and the coder, which has a shorter average code length, is completed.