minimax approximation of FIR filter
[hn]=eqfir(nf,bedge,des,wate)
number of output filter points desired
Mx2 matrix giving a pair of edges for each band
M-vector giving desired magnitude for each band
M-vector giving relative weight of error in each band
output of linear-phase FIR filter coefficients
Minimax approximation of multi-band, linear phase, FIR filter