In the last edition of Don’t Fear the Filter, we built up two examples of the simplest and most-used active filter of all time: the two-pole Sallen-Key lowpass. This time, we’re going to put two of ...

When you design an analog, lowpass, antialiasing filter, you would expect its gain amplitude to continuously decrease beyond the filter's cutoff frequency. For the most part, this assumption is a safe ...

RP Sallen and EL Key of the Massachusetts Institute of Technology’s Lincoln Laboratory in 1955 introduced the Sallen-Key analog filter topology. Engineering literature extensively discusses the second ...

Filters aren’t exactly glamorous things. Yet the job they do in holding back nasties of various sorts means they’re essential to the good health of any engine or hydraulic system. And as farm ...