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进行无限冲击响应(IIR)数字滤波器的无约束Chebyshev设计时,得到的滤波器幅值响应通常在过渡带存在明显过冲现象,且通带边缘的群延迟误差较大。本文提出一种序列约束Chebyshev(SCC)方法,在通带和阻带最大频率响应(FR)误差小于某给定值ρ的条件下,使过渡带频率响应误差(相对某个具有单调幅值特性的过渡响应函数)的Cheby-shev模最小,并通过收缩和对分找出ρ的最小值。该方法不但可以使通带和阻带最大频率响应误差尽可能小,还能减小过渡带幅值响应的过冲以及带边群延迟误差。仿真实例表明了该方法的有效性。
For the unrestricted Chebyshev design of an infinite impulse response (IIR) digital filter, the resulting amplitude response of the filter usually has a significant overshoot in the transition band and a large group delay error at the edge of the pass band. In this paper, we propose a sequence-constrained Chebyshev (SCC) method. Under the condition that the error of the maximum frequency response (FR) of the passband and stopband is less than a given value ρ, the frequency response error of the transition band Of the transitional response function) of the Cheby-shev mode minimum, and through the contraction and bisection to find the minimum value of ρ. This method can not only minimize the maximum frequency response error of passband and stopband, but also reduce the overshoot of the amplitude response of the transitional band and the delay error of the edgeband group. The simulation example shows the effectiveness of the method.