Application of frequency-response masking technique to the design of a novel modified-DFT filter bank

Abstract

Modified-DFT (MDFT) filter banks permit subchannels with linear phase characteristics, and provide high degrees of computational efficiency. However, in MDFT filter banks with subchannels exhibiting narrow transition-bandwidths, the length of the prototype filter becomes prohibitively long, reducing the computational efficiency. It is well known that the frequency-response masking (FRM) technique provides an attractive technique for the realization of digital filters with very narrow transition-bandwidths. In this paper, the FRM digital filter design technique is exploited and applied to the design of a novel cascaded MDFT filter bank realizing selective subchannels with very narrow transition-bandwidths. An application example is given to illustrate the design of the proposed MDFT filter bank. It is shown that the resulting filter bank entails substantially less computational complexity compared to the conventional MDFT filter banks.