Compensation of clock feedthrough induced offset in analog adaptive FIR filters based on the LMS algorithm

Offset voltage due to clock feedthrough in the adapting part of analog least mean square (LMS) adaptive filters causes serious degradation of the filter´s convergence and error performance. A compensation scheme and its circuit level implementation are described. The scheme eliminates the clock-induced offset because the latter is the same for all weight integrators. Computer simulations at both algorithmic and circuit level are presented. They demonstrate the effectiveness of this offset cancellation scheme