Two-Rate Based Low-Complexity Time-Varying Discrete-Time FIR Reconstructors for Two-Periodic Nonuniformly Sampled Signals

This paper deals with time-varying finite-length impulse response (FIR) filters used for reconstruction of two-periodic nonuniformly sampled signals. The complexity of such reconstructors increases as their bandwidth approaches the whole Nyquist band. Reconstructor design that yields minimum reconstructor order requires expensive online redesign while those methods that simplify online redesign result in higher reconstructor complexity. This paper utilizes a two-rate approach to derive a single-rate structure where part of the complexity of the reconstructor is moved to a symmetric filter so as to reduce the number of multipliers. The symmetric filter is designed such that it can be used for all time-skew errors within a certain range, thereby reducing the number of coefficients that need online redesign. The basic two-rate based reconstructor is further extended to completely remove the need for online redesign at the cost of a slight increase in the total number of multipliers.