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Abstract

An oversampled filter bank structure that can be implemented using popular and efficient fast filter banks to allow subband processing of an input signal with substantially reduced aliasing between subbands. Even subbands (SB0, SB2, SB4, . . . ) of an input signal (x(n)) are frequency-shifted (212, 1012, 1012′, 1012') prior to analysis filtering (214, 214′, 214') at a 2× oversampled filter bank, subband processing (240, 240′, 240'), and synthesis filtering (216, 216′, 216'). A subsequent frequency-shift (218, 218′) returns the even subbands to their original band positions. The odd subbands (SB1, SB3, SB5, . . . ) are delayed (252) to compensate for the processing time of the frequency shifting. Separate analysis (214, 214′) and synthesis (216, 216′) filter banks may be provided for the even and odd subbands, or common complex analysis (284) and synthesis (286) filter banks may be used. In another embodiment, the subbands are processed in four subband paths (Paths 0, 1, 2, 3), and 4× oversampling is used. A filter bank structure (1400) for 2-D data is also provided.

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First Claim