X. Zhang et H. Iwakura, DESIGN OF DIGITAL ALLPASS FUNCTIONS WITH SPECIFIED PHASE TOLERANCES, Electronics and communications in Japan. Part 3, Fundamental electronic science, 78(8), 1995, pp. 1-9
In this paper, a new method is introduced for designing IIR digital al
lpass functions with specified phase tolerances. Since the phase error
characteristics subject to the desired phase response have been speci
fied in the interest bands, the phase design of digital allpass functi
ons in the form of a linear programming problem can be formulated by u
sing the Remez exchange algorithm. Then the linear equations are solve
d to obtain a set of filter coefficients and the optimal coefficients
in the Chebyshev sense can easily be obtained through a few iterations
. By appropriately selecting the initial extremal frequencies, the pro
posed design algorithm always converges, and the phase error character
istics can be arbitrarily specified. Finally, some design examples are
presented to demonstrate the effectiveness of the proposed method.