Scilab Function

find_freq - parameter compatibility for elliptic filter design

### Sequence d'appel

  `[m]=find_freq(epsilon,A,n)`

### Parametres

- `epsilon` : passband ripple
- `A` : stopband attenuation
- `n` : filter order
- `m` : frequency needed for construction of elliptic filter

### Description

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`.

### Voir aussi

`%k`

### Auteur

F. D.