A pitch lag coding device and method using interframe correlation inherent in pitch lag values to reduce coding bit requirements. A pitch lag value is extracted for a given speech frame, and then refined for each subframe. For every speech frame having N samples of speech, LPC analysis and vector quantization...http://www.google.de/patents/US6345248?utm_source=gb-gplus-sharePatent US6345248 - Low bit-rate speech coder using adaptive open-loop subframe pitch lag estimation and vector quantization
