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.

Approaches to high quality speech coding using gain-adaptive vector quantization

Abstract: Preliminary results of ongoing research to utilize vector quantization to achieve practical high quality speech coding at 8 kb/s are reported. The basic concepts of speech coding and vector quantization are discussed, followed by a description of the gain adaptive time domain vector quantizer and the gain adaptive transform domain vector quantizer. The quantitative and qualitative performance of the proposed coding systems is presented. >

The LD-CELP Gain Filter Based on BP Neural Network

Abstract: The recommendation G.728 depends on the Levinson-Durbin (L-D) algorithm to update its gain filter coefficients. In this paper, it is contrasted with BP neural network method. Because quantizer has not existed at optimizing gain filter, the quantization SNR can not be used to evaluate its performance. This paper proposes a scheme to estimate SNR so that gain predictor can be separately optimized with quantizer. Using BP neural network filter, the calculation quantity is only 6.7 percent of L-D method’s and its average segment SNR is about 0.156dB higher than G.728. It is also used to evaluate the case that excitation vector is 16 or 20 samples, respectively, the BP neural network algorithm has similarly good result.

Encoding of voice signal

Abstract: PURPOSE: To encode the signal of low bit speed by taking-out a de-emphasized short-term residual signal from a first voice part and taking-out a longterm residual signal by means of code excited linear prediction(CELP) encoding from it CONSTITUTION: The signal to be transmitted is digitally PCM-encoded, the sample is pre-empharized by a PRE-EMP device 10 so as to be processed by a correlation unit 12 and a partial autocorrelation coefficient for adjusting a short-term prediction filter 13 is generated Then, it is added to the short-term residual signal generated in the filter 13 so as to be adopted as the long-term residual signal and the continuous samples are divided into blocks After that, the blocksamples are processed by a code excited linear prediction encoder 14, converted into a usable codeword and adopted as the code being storage possible at low speed Then, it is transmitted to a multiplexer 17, the output of the filter 13 is also inputted to the multiplexer 17 with a calculating device 9, a long-term prediction loop 15 and addition mechanism 16 so as to be multiplexed and transmitted to DMPX 18 of a receiving/decoding equipment