GFARFS: Compute   and  optionally   plot  gain   and   phase   functions   of
         autoregressive  or  difference  filter;  with  user-supplied  control
         values;  return  gain and  phase function  values  and  corresponding
         frequency values

         REAL PHI(iar), GAIN(nf), PHAS(nf), FREQ(nf)
         DOUBLE PRECISION DSTAK(ldstak)
         COMMON /CSTAK/ DSTAK
         :
         :
         CALL GFARFS (PHI, IAR,
        +             NF, FMIN, FMAX, GAIN, PHAS, FREQ, NPRT, LDSTAK)


 Argument definitions are given in the on-line STARPAC User's Guide.
 The ACCESS document describes how to print a copy of the Guide.