Patent ID: 8352255

Claim:
A speech decoding method according to code-excited linear prediction (CELP), the method comprising: receiving a coded speech signal including a linear prediction parameter code, a gain code, and an adaptive code; obtaining an adaptive code vector from an adaptive codebook based on the received adaptive code; decoding a set of gains from the received gain code in a decoding period corresponding to the coded speech signal; obtaining a time series vector with a number of samples with zero amplitude-value from an excitation codebook; selectively modifying the time series vector based on at least one gain from the set of decoded gains such that the number of samples with zero amplitude-value is changed; weighting the adaptive code vector and the selectively modified time series vector using the set of decoded gains; adding together the weighted adaptive code vector and the weighted time series vector; decoding a linear prediction parameter from the received linear prediction parameter code; and synthesizing a speech signal using the linear prediction parameter and the added weighted adaptive code vector and weighted time series vector.