Spar Aerospace Limited

Ems Technologies Canada, Limited

Mohammad Reza Soleymani

Yousef Shayan

A filter network demultiplexes a frequency division multiplexed input signal which involves a reduced number of multiplier or multiplying steps. The filter network comprises L&minus;1 Z shift registers in series receiving the multiplexed input signal Y(n) to produce L&minus;1 corresponding shifted signals, pairs of which are added. The filter network further comprises a set of q multiplier sections including p first multiplier sections each being coupled to the added signals for combining each output of a corresponding set of N transformed filter coefficients g . There are provided a set of N second adder sections each being coupled to distinct outputs of the multiplier sections for producing a corresponding set of N transformed signals, and a set of t third adders each receiving a distinct pair of signals &lcub;C (n),C (n)&rcub; from the transformed signals C (n) for producing a first filtered signal A (n) and a set of N&minus;1 filtered signals A (n&plus;k), with k&equals;1, . . . , N&minus;1.

Apparatus and method for demultiplexing a frequency division multiplexed input signal and polyphase digital filter network therefor

A half-band filter for cellular group demultiplexer has a top half and a symmetrical bottom half. Each half consists of a plurality of shift registers, adders and multipliers connected in serial arrangement so as to produce a desired result at the output whereby the number of multipliers is reduced relative to the amount of multipliers in a conventional half-band filter.

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Beaconsfield, Canada

Mohammad Reza Soleymani