WARPEDBLFILTER Construct a warped band-limited filter
Usage: g=warpedblfilter(winname,fsupp,fc,fs,freqtoscale,scaletofreq);
Input parameters:
winname : Name of prototype.
fsupp : Support length of the prototype (in scale units).
fc : Centre frequency (in Hz).
fs : Sampling rate
freqtoscale : Function handle to convert Hz to scale units
scaletofreq : Function to convert scale units into Hz.
Output parameters:
g : Filter definition, see BLFILTER.
WARPEDBLFILTER(winname,fsupp,fc,fs,freqtoscale,scaletofreq) constructs
a band-limited filter that is warped on a given frequency scale. The
parameter winname specifies the basic shape of the frequency response.
The name must be one of the shapes accepted by FIRWIN. The support of
the frequency response measured on the selected frequency scale is
specified by fsupp, the centre frequency by fc and the scale by the
function handle freqtoscale of a function that converts Hz into the
choosen scale and scaletofreq doing the inverse.
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.
WARPEDBLFILTER accepts the following optional parameters:
'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.
'symmetric' The filters with fc<0 (or fc>fs/2) will be created
on the positive frequencies and mirrored. This allows
using freqtoscale defined only for the positive
numbers.
'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 filterbank.
It is possible to normalize the transfer function of the filter by
passing any of the flags from the NORMALIZE function. The default
normalization is 'energy'.
The filter can be used in the PFILT routine to filter a signal, or
in can be placed in a cell-array for use with FILTERBANK or
UFILTERBANK.
The output format is the same as that of BLFILTER.
Url: http://ltfat.github.io/doc/sigproc/warpedblfilter.html
See also: blfilter, firwin, pfilt, filterbank.
Package: ltfat