Method for estimating fractional base sound of code excitation linear predicted speech encoder

Abstract

A method for estimating fractional fundamental tone of code-excited linear prediction voice coder includes making open-loop fundamental tone estimation on object signal, calculating estimation value of open-loop integer fundamental tone, making open-loop fundamental estimation and calculating close-loop correlation sequence, solving out peak value position according to peak value point situation of close-loop correlation sequence and carrying out linear quantization on peak value position as per interpolation value D to obtain estimated value of fractional fundamental tone.

Description

technical field [0001] The invention belongs to the field of voice communication, in particular to a fractional pitch estimation method for a code-excited linear prediction speech coder. Background technique [0002] Code Excited Linear Prediction (Code Excited Linear Prediction, CELP) comprehensively utilizes the short-term prediction characteristics, long-term prediction characteristics and vector quantization method of speech to obtain coding gain, and has been widely used in low-bit-rate speech communication. Pitch period estimation is one of the key factors affecting prediction gain in long-term prediction. In the digitization process of the speech signal, since the pitch period of the speech signal is usually not an integer multiple of the sampling interval T, if the integer pitch prediction is directly used, the pitch period obtained in the discrete domain will be -0.5T~ 0.5T mismatch. If fractional pitch estimation is used, the gain reduction caused by this mismatc...

AI Technical Summary

Problems solved by technology

However, the existing fractional pitch estimation method has the following defects: the fractional pitch estimation value required for the long-term prediction of the first-order fraction only represents the position of the peak value of the interpolation sequence, rather than the peak value; on the other hand, the interpolation composed of upsampling and low-pass filtering Filter cannot accommodate variable interpolation factors

Therefore, in the prior art, the realization of fractional pitch estimation requires interpolation and comparison operations, the algorithm is complex and the memory overhead is large, and the efficiency of obtaining the fractional pitch estimation value is low.

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