chebyshev ( <order> , <ripple> ) ;with
results in a Chebyshev cascade filter. Its bandwidth is 1rad/s. If the ripple is zero, the bandwidth is the frequency where the damping is -3 dB. If the ripple is nonzero, the bandwidth is the highest frequency where the damping equals the ripple.
<order> : integer; order, <ripple> : real; ripple in dB