ENCODER FOR WIDEBAND LOW TRANSMISSION RATE VOICE SIGNAL

摘要

PURPOSE: An encoder for a wideband low transmission rate voice signal is provided to efficiently encode the wideband low transmission rate voice signal for a voice signal interval discriminated as silence. CONSTITUTION: A pre-processing and down sampling block(501) down-samples a voice signal frame sampled as a high frequency into a voice signal frame with a low frequency, and generates a voice signal frame in which a DC component is removed. An LPC(Linear Prediction Coding) analysis and ISP(Immittance Spectral Pair) quantization block(502) receives a down-sampled voice signal frame, obtains an LPC coefficient of the frame, converts the coefficient into ISP, quantizes the ISP, and generates an index of the ISP. A residual signal computation block(503) obtains a residual signal for modeling an exciting signal of an analysis filter of the down-sampled voice signal. A random vector generation block(505) generates a random vector for modeling the exciting signal. A gain computation block(506) calculates a gain for scaling the random vector. A gain quantization block(508) quantizes the gain, and generates an index of the gain.