Speech coding apparatus capable of implementing acceptable in-channel transmission of non-speech signals

摘要

A speech coding apparatus includes a frequency parameter generating unit that generates LSP coefficients of an input signal. When the input signal is a non-speech signal, it generates the LSP coefficients of the non-speech signal in such a manner that they approach the LSP coefficients of the speech signal. Thus, even when the input signal is the non-speech signal, its LSP coefficients are quantized by referring to the LSP quantization codebook which is specifically prepared for the speech signal. Although a conventional speech coding apparatus has a problem in that even when it transmits the non-speech signal in a good condition, a conventional speech decoding apparatus cannot always decode the non-speech signal correctly, the present speech coding apparatus can solve the problem even when the receiving side uses the conventional speech decoding apparatus.