Efficient filtering with a complex modulated filterbank

Abstract From the Canadian patent

A filter apparatus for filtering a time domain input signal to obtain a time domain output signal, which is a representation of the time domain input signal filtered using a filter characteristic having an non-uniform amplitude/frequency characteristic, comprises a complex analysis filter bank (101) for generating a plurality of complex subband signals from the time domain input signals, a plurality of intermediate filters wherein at least , one of the intermediate filters (102) of the plurality of the intermediate filters has a non-uniform amplitude/frequency characteristic wherein the , plurality of intermediate filters have a shorter impulse response compared to an impulse …