Commutativity and Application of Digital Interpolation Filters and Modulators

Interpolation filters are being widely used in a variety of communication applications. An equivalent realization of an interpolation FIR filter is shown to be a cascade combination of a hold and a periodically varying filter. It is also shown that the periodicity of the filter results in the Commutativity of the filter and a sinusoidal modulator. An application of such a scheme to TDM-FDM transmultiplexer is also presented.