Frequency-domain magnitude constraints for oversampling complex-modulated NPR filter bank system design ensuring prescribed signal-to-distortion ratio
Design approaches for oversampling complex-modulated analysis-synthesis filter bank systems (FBSs) have to control multirate disturbances due to down- and upsampling. Common design methods minimise multirate disturbances by optimising an objective function for arbitrarily given filter lengths. In contrast, approximate frequency-domain magnitude constraints are derived for FBS prototype filters such that a prescribed signal-to-distortion ratio of the FBS output signal is ensured. It is shown that these constraints can be met both by linear-phase equiripple and dedicated FBS filter design algorithms. Without the need of occupying the objective function of a (constrained) filter optimisation to minimise FBS disturbance, the resulting performance is close to that achieved with a current design method.