Thinning the impulse response of FIR digital filters

The design and performance of finite duration impulse response (FIR) digital filters with nonuniform tap spacings is examined. It is shown that a reduction in filter order can be achieved with a relatively small sacrifice in performance by thinning a high order uniformly spaced impulse response. The process of optimally selecting the tap spacings to minimize the statistical mean-squared estimation error is discussed and alternative procedures for implementation of the selection mechanism are mentioned. The results apply to more general estimation problems where control can be exercised over the selection of data to be incorporated into the estimator structure.