This voice messaging system provides an LPC analyzer in combination with a pitch extractor wherein LPC parameters and a residual signal organized in a sequence of speech data frames are provided by the LPC analyzer as an output representative of an analog speech signal. The pitch extractor is operably...http://www.google.com/patents/US4696038?utm_source=gb-gplus-sharePatent US4696038 - Voice messaging system with unified pitch and voice tracking
