| 摘要 |
The process for detection and masking of bad frames in a coded speech signal resulting from channel transmission errors has been improved. The coded speech signal has a first group of bits comprising the most perceptually significant bits of the coded speech signal, a second group of bits comprising the second most perceptually significant bits and a third group of bits comprising the least perceptually significant bits. The coded speech signal is de-interleaved to obtain a first series of bits comprising the first and second group and a second series of bits comprising the third group of bits. The first series of bits are convolutionally decoded for recovering the first and second group of bits, with the first group of bits containing error protected bits. A CRC check is performed by sending the recovered bits of the first group to cyclic redundancy decoding means. The first group of bits is forwarded to speech decoder means if the CRC check is successful. The frame energy and LPC parameters are replicated for the first and third group of bits and the frame energy, LPC parameters, lag value and sub-frame gain are replicated for the second group of bits, and subsequently the replicated bits are forwarded to the speech coder means, if the CRC check is not successful.
|
