Patent ID: 8626808

Claim:
A digital signal processing circuit, the circuit comprising: a band selector ( 14 ) for selecting at least one sub-band from a frequency spectrum of a digital sampled input signal, the band selector ( 14 ) comprising a plurality of processing branches corresponding to respective phases and an adder ( 28 a , 28 b ) for adding branch signals from the processing branches, at least two processing branches, each of the processing branches comprising: a sub-sampler ( 20 a,b ) for sub-sampling sample values of the input signal at the phase corresponding to the branch; a filter ( 24 a,b ) comprising a first FIR filter ( 32 , 34 ), applied alternatingly to sets of sub-samples from the sub-sampler ( 20 a,b ) at even sub-sample positions and to sets at odd sample positions, and a second FIR filter ( 36 , 38 ) applied to further sets of sub-samples at odd and even sub-sample positions from the sub-sampler ( 20 a,b ), when the first FIR filter is applied to the sets of sub-samples at even and odd sub-sample positions respectively; and a combiner ( 26 a,b ) for combining output samples from the first and second FIR filters ( 24 a,b ) into the branch signals of the branch, according to a combination pattern that changes cyclically as a function of sub-sample position, and depends on the phase of the branch.