Patent ID: 6856955

Claim:
A voice coding apparatus comprising: a spectrum quantization circuit for calculating and quantizing a spectrum parameter of a voice signal; an adaptive code book circuit for predicting said voice signal from a sound source signal to calculate a residual; a sound source quantization circuit for quantizing said sound source signal by using said spectrum parameter to output the quantized sound source signal; a gain quantization circuit for quantizing a gain of said sound source signal; a mode decision circuit for extracting characteristics from said voice signal to decide a mode; and a multiplexer unit for multiplexing an output from said spectrum parameter quantization circuit, an output from said mode decision circuit, an output from said adaptive code book circuit, an output from said sound source quantization circuit, and an output from said gain quantization circuit to output the multiplexed result, characterized in that: when the output from said mode decision circuit represents a predetermined mode, said sound source signal is represented by a combination of a plurality of pulses wherein an amplitude or polarity of the pulse is calculated from said voice signal; and said sound source quantization unit selects a shift amount and a code vector, which minimize distortion between an input signal and a reproduced signal, from combinations of a plurality of shift amounts by which the pulses shift and gain code vectors.