The Harmonic-Noise Speech Coding Algorhthm Using Cepstrum Analysis Method

PURPOSE: A harmonic-noise speech coding system and method using cepstrum analysis are provided to enable effective coding through harmonic-noise speech coding algorithm that estimates noise spectral component to offer improved sound quality. CONSTITUTION: A harmonic-noise speech coding system(100) includes a noise-spectral estimator that separates noise from an input LPC residual signal using cepstrum and estimates spectral through LCD analysis to code the noise. The noise-spectral estimator includes a log value extracting means for extracting negative log value spectrum of the cepstrum extracted through the cepstrum analysis, and an amplitude extracting means for extracting a valley portion of mixed signal spectral, corresponding to the negative log value spectrum region. The noise-spectral estimator further has an LPC analyzer for extracting spectral information of the extracted noise spectral, an LSP converter for converting extracted LPC parameters into LSP parameters, and a gain calculator for calculating the gain of noise component.