Design algorithm for multichannel interleave filters

A one-input M-output (1 x M) circuit configuration and design algorithm for an interleave filter with M output ports (M >= 2) are presented. The circuit configuration is composed of a 1 x M optical lattice filter with a delay time of M Delta tau (Delta tau: unit delay time), an M x AT diagonal delay matrix circuit, and an M x M modified inverse discrete Fourier transform matrix circuit. The proposed circuit with M = 2 corresponds to a conventional interleave filter. The proposed synthesis algorithm is based on polyphase decomposition and yields circuit parameters ensuring that every output characteristic has an Mth-band property. A five-channel interleave filter is presented as an example of the design procedure.