Model reduction of digital systems using discrete Walsh series

This study discusses the application of discrete Walsh series expansion to reduce the order of a linear time-invariant digital system described by
z
-transfer function. The approach is based on matching the discrete Walsh spectra to determine both the coefficients of the denominator and numerator of the reduced model. The proposed method is simple for computation, can preserve the dynamic characteristic of the original model satisfactorily, and guarantees to have the same zero initial response as the original system.