A recursive digital filter with simultaneous maximally flat magnitude and group delay at an arbitrary specified frequency
P. Thajchayapong, P. Karnchanawadee, F. Cheevasuvit · Proceedings of the IEEE · 1979
A design technique for a recursive digital filter with simultaneously maximally flat magnitude and group delay at an arbitary specified frequency is presented, It employs the power series expansion to formulate a set of simultaneous linear equations which can be solved with a standard computational algorithm.