FILTERBANK - Wrapper around filter to multiple filtersUsage:
Description:FILTERBANK(b,a,insig) filters the input signal with the filters described in a and b.
FILTERBANK(b,a,insig,hopsize) does the same, but only outputs every hopsize sample in the time domain.
If a and b are matrices then each row corresponds to a subband channel.
If insig is a matrix then filtering is applied along the columns.
If both insig, a and b are matrices the output will be 3-dimensional. First dimension is time, second dimension is frequency channel third dimension corresponds to the column of the input signal.