Compute chebyshev type I filter order and cutoff for the desired response
characteristics. Rp is the allowable decibels of ripple in the pass
band. Rs is the minimum attenuation in the stop band.

[n, Wc] = cheb1ord(Wp, Ws, Rp, Rs)
Low pass (WpWs) filter design.  Wp is the
pass band edge and Ws is the stop band edge.  Frequencies are
normalized to [0,1], corresponding to the range [0,Fs/2].

[n, Wc] = cheb1ord([Wp1, Wp2], [Ws1, Ws2], Rp, Rs)
Band pass (Ws1