FILTERBANKREALDUAL Dual filters of filterbank for real signals only
Usage: gd=filterbankrealdual(g,a,L);
gd=filterbankrealdual(g,a);
FILTERBANKREALDUAL(g,a,L) computes the canonical dual filters of g*
for a channel subsampling rate of a (hop-size) and a system length L.
L must be compatible with subsampling rate a as
L==filterbanklength(L,a). The dual filters work only for real-valued
signals. Use this function on the common construction where the filters
in g only covers the positive frequencies.
filterabankrealdual(g,a) does the same, but the filters must be FIR
filters, as the transform length is unspecified. L will be set to
next suitable length equal or bigger than the longest impulse response.
The format of the filters g are described in the help of FILTERBANK.
In addition, the function recognizes a 'forcepainless' flag which
forces treating the filterbank g and a as a painless case
filterbank.
To actually invert the output of a filterbank, use the dual filters
together with 2*real(ifilterbank(...)).
REMARK: Perfect reconstruction can be obtained for signals of length
L. In some cases, using dual system calculated for shorter L might
work but check the reconstruction error.
Url: http://ltfat.github.io/doc/filterbank/filterbankrealdual.html
See also: filterbank, ufilterbank, ifilterbank.
Package: ltfat