Design of two-channels FIR filterbanks with rational sampling factors using the FRM technique

The design of finite-impulse response (FIR) filters is considered for generating nearly perfect-reconstruction two-channel filterbanks (FB) with rational sampling factors. In order to ensure a good FB performance when there are significant changes in the subband signals, the filters in the FB must have very narrow transition bandwidths. This implies the use of high order FIR filters with a high arithmetic complexity. This paper shows how this complexity can be significantly reduced by properly exploiting the frequency-response masking technique when designing FIR filters in the FB. The benefits of the proposed approach are illustrated by means of an example.