Automatic h-register clear for prevention of erroneous convolution in digital adaptive echo canceller

Abstract From the Canadian patent

An automatic H-register clear system for the prevention of erroneous convolution in adaptive digital echo cancellers is disclosed. Incoming signals from the Hregister are accumulated and compared to a predetermined threshold value and when the value is exceeded the H-, register is cleared with the occurrence of the internal housekeeping cycle of the echo canceller. The clearing of the H-register allows a new impulse responsive model to be generated from new sampled data. In one embodiment using analog implementation, the accumulation takes place using a sequence of signal processing of digital-to-analog conversion full wave rectification followed by integration of the signal. In another …