Low bit rate voice coding method and device

摘要

In a base-band voice coder, low bit rate is achieved by selectively defining the frequency bandwidth the contents of which is to be considered representative of the voice signal and be coded accordingly. The voice terminal signal x(n) is split into a low-pass filtered band signal y1(n) and a high-pass filtered band signal y2(n). Both y1(n) and y2(n) signals are coded into lower-rate sub-sequences of samples x1(n), x2(n) and x3(n), x4(n) respectively. The sequence of samples to be representative of x(n) is selected among x1(n), x2(n), x3(n) and x4(n) for being the closest to x(n).