Tree-structured linear-phase Nyquist FIR filter interpolators and decimators

This paper introduces a new class of linear-phase Nyquist (Mth-band) FIR interpolators and decimators based on tree structures. Through design examples, it is shown that the proposed converter structures have a substantially lower computational complexity than the conventional single-stage converter structures. The complexity is comparable to that of multi-stage Nyquist converters, although the proposed ones tend to have a somewhat higher complexity. A main advantage of the proposed structures is however that they can be used for arbitrary integer conversion factors, thus including prime numbers which cannot be handled by the regular multi-stage Nyquist converters.