| 摘要 |
A multirate filter according to the invention comprises, a) an input unit ( 10 ) for receiving an input signal (Sin) and for providing a plurality of intermediate signals (IS 1 , IS 2 ) in response to said input signal, b) a filter unit ( 20 ) coupled to the input unit ( 10 ), and c) an output unit ( 30 ) coupled to the filter unit ( 20 ), for generating an output signal (Sout). The filter unit ( 20 ) comprises at least a first and a second filter module ( 21, 22 ), with a transfer function H<SUB>0</SUB>(z) and a transfer function H<SUB>1</SUB>(z) respectively, which are mutually related according to the relations H<SUB>0</SUB>(z)=c<SUB>0</SUB>(H<SUB>B</SUB>(z)+M<SUB>alpha,psi</SUB>H<SUB>B</SUB>(z)) and, H<SUB>1</SUB>(z)=c<SUB>1</SUB>(H<SUB>B</SUB>(z)+M<SUB>alpha,psi</SUB>H<SUB>B</SUB>(z)) wherein, M<SUB>alpha,psi</SUB>(H<SUB>B</SUB>(z))=alphaz<SUP>-2psi</SUP>H<SUB>B</SUB>*(z<SUP>-1</SUP>), and wherein Formula (I), being the z-transform of h<SUB>b</SUB>[m]. The multirate filter comprises a combination unit ( 11 ) coupled to said filter modules ( 21, 22 ) for generating a first combination signal (Ssum) and a second combination signal (Sdiff).
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