An exact method is presented, for the construction of bandpass digital, (or microwave) filters with maximally flat delay at arbitrary specified frequency. It is based upon the solution of a second-order differential equation with eigenvalues. The case of filters with simultaneous flat amplitude and delay is also considered. Illustrative examples are also provided.
John David RhodesM. I. F. Fahmy
T. SaramäkiY. NeuvoT. Saarinen