Echo Cancellers - How to improve satellite circuit performance

It is pointed out that an echo canceller differs from an echo suppressor in that rather than attenuating an echo in the return path, it digitally computes an echo estimate that is then subtracted from the return-path signal. It is shown that because of the completely adaptive nature of the echo canceller design, it can cancel echo in any circuit whose end path has at least 6 dB of echo return loss and less than 30 ms of propagation delay. The cross-correlative operation of the echo canceller ensures that it is much more immune to false operation by either echo or noise. And because there is no receive suppression in the echo canceller, the problem of lockout is totally eliminated.