The Chebyshev filter is optimum in the sense that for a given pass band and stop band levels, it has the smallest transition region (Ws Wp) of any filter that consists only of finite poles. Such all poles filters have all their zeros at s = infinity. The Chebyshev characteristic provides an alternative way of obtaining a suitable analog transfer function, H(s). Two categories of Chebyshev filters, called types I and II. Type I Chebyshev filter has equal ripple in the pass band, and is monotonic in the stop band. Type II Chebyshev filter, on the other hand, has equal ripple in the stopband, and is monotonic in the passband.