.\" @(#)optfir	1.1	11/2/90
.H1 "optfir \(em equirriple FIR filter design"
.pp
Optfir is a Fortran program performing classical FIR filter design
using the Parks-McClellan algorithm.  There is nothing unusual
about this program, so almost any DSP book will give an adequate
explanation of the algorithm as well as the meaning of its arguments.
Briefly, the program permits the design of bandpass filters,
differentiators, hilbert transformers, and half-band filters.
.pp
Bandpass filters include lowpass, highpass, bandstop, and multiband, where
each band can have a different gain (the "desired value").
A desired value of 0 specifies a stopband.
The weight associated with each band determines the ratio of ripple
in each band; a higher weight means less ripple.
