Alternative subband signal structures for complex modulated filter banks with perfect reconstruction

In this paper, two critically sampled perfect reconstruction complex modulated filter banks, used with complex-valued input signals, are compared. The modified discrete Fourier transform filter bank (MDFT-FB) and the recently introduced exponentially modulated filter bank (EMFB) have different approach for critical sampling and they use different channel stacking agreement. It is shown that with certain special modifications, the EMFB system can provide exactly the same subband signal values for the subband processing as the MDFT-FB system. An intuitive and simple spectral interpretation of these modifications and alternative spectral structure of the subband signals are also given.