Adaptive filter implementation using switched-current technique

A CMOS switched-current adaptive filter architecture is presented. It is basically a finite impulse response (FIR) transversal filter adapted by using the Least-Mean-Square (LMS) adaptation algorithm. The design is based on delay and multiply-accumulator blocks. The implemented system can be switched to work either as an adaptive filter or as an FIR programmable filter. The adaptation signal can also be switched to allow for external control. Simulation results from a 4-tap FIR-LMS adaptive filter are also presented.