The present invention relates to a pitch retrieval method using a correlation characteristic of quantization error that can shorten the pitch retrieval time of a CELP speech coder for compressing speech in digital voice communication.;In the conventional CELP speech coder, the pitch search uses a closed loop sequential search method, which occupies about 50% of the total encoding processing time, whereas the present invention normalizes the quantization error signal of the input speech signal and then decimates it. It is a pitch search method that can save the pitch search time by selecting only the intervals forming a positive peak as a preliminary pitch interval by obtaining the autocorrelation equation through the process and performing the pitch search only for the preliminary pitch interval.;When CELP encoding is performed on the actual speech using the pitch search method proposed by the present invention, the objective predictive gain is reduced to -0.10 dB on average compared to the sequential pitch search, but the pitch search time is about 40.6 compared to the sequential pitch search method. % Was reduced. Since the deterioration of the sound quality is mainly generated in the unvoiced sound interval, the subjective sound quality deterioration was not felt compared to the sequential pitch search.
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