iirgroup

iirgroup — group delay Lp IIR filter optimization

Calling sequence

[lt,grad]=iirgroup(p,r,theta,omega,wt,td)  
[cout,grad,ind]=iirlp(x,ind,p,[flag],lambda,omega,ad,wa,td,wt)

`r`	: vector of the module of the poles and the zeros of the filters
`theta`	: vector of the argument of the poles and the zeros of the filters
`omega`	: frequencies where the filter specifications are given
`wt`	: weighting function for and the group delay
`td`	: desired group delay
`lt, grad`	: criterium and gradient values

optimization of IIR filters for the Lp criterium for the the group delay. (Rabiner & Gold pp270-273).