parameter compatibility for elliptic filter design
[m]=find_freq(epsilon,A,n)
:epsilon passband ripple : :A stopband attenuation : :n filter order : :m frequency needed for construction of elliptic filter :
Search for m such that n=K(1-m1)K(m)/(K(m1)K(1-m)) with
m1=(epsilon*epsilon)/(A*A-1);
If m = omegar^2/omegac^2, the parameters epsilon,A,omegac,omegar and n are then compatible for defining a prototype elliptic filter. Here, K=%k(m) is the complete elliptic integral with parameter m.