Tachometer signal smoothing with analog discrete-time polynomial estimators

The design of sampled-data polynomial estimators for noise reduction in industrial instrumentation applications is discussed. Unlike conventional lowpass filters, an estimator causes no delay on the polynomial-like primary signal. A general purpose design approach is described, incorporating notch frequencies for removal of narrow-band noise components, such as the 50/60 Hz line frequency. A 24-tap FIR estimator is optimized for tachometer signal smoothing in motor control systems. An analog circuit architecture, targeted for silicon CMOS implementation, is described and simulated.