An integrated voice codec and echo canceller implemented in a single DSP processor

A new Linear Predictive Echo Canceller (LPEC) is presented which modifies the classical echo canceller structure to pre-whiten the input signal and hence have better convergence properties in the presence of highly correlated input signals such as speech. This structure is integrated with a 16 KBPS Residual Excited Linear Predictive (RELP) Vocoder [1] to allow significant execution speed savings by sharing common processing modules. The integrated LPEC has been implemented in the Vocoder Demonstration System (VDS-20) using a single TMS32020 processor and will be available at the conference for demonstrations.