A microprocessor-based memory-tap echo canceler

Echo cancellation in two-wire full-duplex data transmission is usually performed with data-driven transversal filters. In this paper, we propose a new scheme for a microprocessor-based digital adaptive echo canceler. We call it "memory-tap echo canceler" (MTEC) because its taps are made of time-delayed L groups of memory registers. Since the estimated echo signals are directly derived from the binary-nature data, the manipulations involved are multiplication-free for any modulation scheme (baseband, or passband). A theoretical analysis of adaptation, convergence, and computational complexity is given, and the convergence characteristic of MTEC is verified by the computer simulations. Finally, we present some preliminary experimental results for an Intel 8086 microprocessor-based 2400 bit/s echo canceler.