Patent ID: 7577696

Claim:
A multirate filter comprising: an input unit for receiving an input signal and for providing a plurality of intermediate signals in response to said input signal, a filter unit coupled to the input unit, an output unit coupled to the filter unit, for generating an output signal, the filter unit comprising at least a first and a second filter module, having a transfer function H 0 (z) and a transfer function H 1 (z) respectively, which are mutually related according to the relations H 0 ( z )= c 0 ( H B ( z )+ M α,ψ H B ( z )) and H 1 ( z )= c 1 ( H B ( z )+ M α,ψ H B ( z )), wherein M α,ψ ( H B ( z ))=α z −2ψ H B *( z −1 ), and wherein H B *( z )=Σh b *[m]z −m , H B ( z ) being the z -transform of h b [ m], H B ( z )= H Rr ( z )=Σ h[Rn+R]z −n , wherein H ( z ) is the z -transform of h[n] and wherein α is an element from the set C of complex numbers and 2ψ is an integer number selected from z, the multirate filter comprising a combination unit coupled to said filter modules for generating a first combination signal and a second combination signal.