Group delay sensitivity of recursive digital filter transfer functions with multiple poles

Studies the group delay sensitivity of recursive digital filters whose group delay frequency response approximates a constant group delay in the Chebyshev sense. A technique is developed which predicts a group delay deviation of recursive digital filters due to changes in digital filter coefficients. It is illustrated that the technique can serve to determine and compare the group delay sensitivity of the transfer function with simple or multiple poles. It is shown that the multiple pole transfer function is less sensitive than a simple pole transfer function.