An echo cancellation algorithm for operation with a digital speech coder in a single signal processor

When introducing a delay in the telephone network, one is likely to hear an echo. Digital cancellers exist, but they need to be initialized. An implementation on a 10-MIPS (million instructions per second) signal processor is reported which uses the speech signal as a training signal while performing voice analysis and synthesis at the same time. The initialization is completed after 3 s of speech and covers a 32-ms window