A Recursive Digital Filter with Maximally Flat Linear Phase at an Arbitrary Specified Frequency

An available recursive digital low-pass filter with constant group delay cannot be spectral transformed to give, for example, a bandpass filter which also has constant group delay. This correspondence describes a technique, using Gauss-Jordan elimination, to design a recursive digital filter with maximally flat linear phase at an arbitrary specified frequency. Copyright © 1978 by The Institute of Electrical and Electronics Engineers, Inc.