Abstract: A programmable frequency identifier circuit for identifying the frequency of a contaminated signal including a digital finite impulse response filter, a zero crossing detector, a zero crossing counter, and a frequency range decoder. The filter is a programmable filter for filtering signals of the form: S(n)=S.sub.1 (n)+S.sub.2 (n)=A cos 2.pi.F.sub.1 (n)+B cos 2.pi.F.sub.2 (n) where S.sub.1 (n)=desired signal, S.sub.2 (n)=contamination, F.sub.1 =passband frequency, F.sub.2 =stopband frequency, and A,B=constants. The zero-crossing counter counts the sign changes occuring during a programmably determined frame time. The number of zero crossings occuring during the frame time is a number representing the desired frequency. The frequency range decoder is programmed with a plurality of frequency range boundaries similarly represented by a count that is based upon the programmable frame time.