How does echo cancellation work?
Almost all (if not all) echo cancelling algorithms operate by generating multiple copies of the received signal, each delayed by some small time increment In digital terms, this is the equivalent of a shift register and each delayed signal appears at its own unique “tap”. The number of taps determines the size of the echo delay that can be cancelled. These delayed copies are then scaled (or weighted) and subtracted from the original received signal. The trick is scaling the the delayed signals to exactly the extent needed to remove the echo and nothing else. The methods used in determining the tap weights (scaling factors) is what distinguishes one algorithm from another.
