Echo detection, tracking, cancellation and noise fill in real time in a communication system

Abstract From the Canadian patent

A method for processing telecommunications signals to alleviate echo during a voice communication between a local talker and a remote talker comprises the application of circular buffers for near and far end signals to preserve processing time. Overlapping blocks of samples are processed and indexed by incrementing the index over time to generate an array for storing magnitude coherence versus time delay between outgoing and incoming samples. Echo is clipped based on power spectral matching. The clipped echo is replaced with noise fill of at least one of two types white noise and tonal noise, at an, appropriate level. Also crackle which comprises high energy spikes and a residual echo …