Patent ID: 7095781

Claim:
A frequency analyzer for analyzing a plurality of input signals x 0 (m) . . . x 1 (m) . . . x M−1 (m), the frequency analyzer comprising: a plurality of input modulators for modulating and shifting said input signals x o (m) . . . x 1 (m) . . . x M−1 (m), defining shifted output signals, wherein said plurality of input modulators include a multiplier for multiplying each of said input signals x o (m) . . . x 1 (m) . . . x M−1 (m) by a factor e −jωn , where n is a time index; a polyphase filter network which includes a plurality of polyphase filters p o (m) . . . p ρ (m) . . . p M−1 (m), each having a coefficient for receiving said shifted output signals and defining polyphase filter output signals; and a plurality of output modulators for modulating the output of said polyphase filters, said frequency analyzer configured to process said plurality of input signals x o (m) . . . x 1 (m) . . . x M−1 (m), wherein each of said plurality of polyphase filters includes a network coefficient and said output modulators include a multiplier for multiplying the output of each of said polyphase filters by a predetermined factor selected so that said coefficients are real.