Function: freqfilter
FREQFILTER Construct filter in frequency domain
  Usage:   g=freqfilter(winname,bw);
           g=freqfilter(winname,bw,fc);

  Input parameters:
     winname  : Name of prototype
     bw       : Effective support length of the prototype
     fc       : Center frequency
  
  FREQFILTER(winname,bw) creates a full-length frequency response
  filter. The parameter winname specifies the shape of the frequency
  response. For accepted shape please see FREQWIN. bw defines a
  -6dB bandwidth of the filter in normalized frequencies.
  
  FREQFILTER(winname,bw,fc) constructs a filter with a centre
  frequency of fc measured in normalized frequencies.

  If one of the inputs is a vector, the output will be a cell array
  with one entry in the cell array for each element in the vector. If
  more input are vectors, they must have the same size and shape and the
  the filters will be generated by stepping through the vectors. This
  is a quick way to create filters for FILTERBANK and UFILTERBANK.
  
  FREQFILTER accepts the following optional parameters:

    'fs',fs     If the sampling frequency fs is specified then the 
                bandwidth bw and the centre frequency fc are 
                specified in Hz.

    'complex'   Make the filter complex valued if the centre frequency
                is non-zero. This is the default.

    'real'      Make the filter real-valued if the centre frequency
                is non-zero.

    'delay',d   Set the delay of the filter. Default value is zero.

    'scal',s    Scale the filter by the constant s. This can be
                useful to equalize channels in a filter bank.

    'pedantic'  Force window frequency offset (g.foff) to a subsample 
                precision by a subsample shift of the window.

Url: http://ltfat.github.io/doc/sigproc/freqfilter.html

Package: ltfat