| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a cascade integrator comb (CIC) filter capable of changing the characteristic of a filter. <P>SOLUTION: A CIC filter including: a circuit where n-stages of integrators IN<SB POS="POST">1</SB>-IN<SB POS="POST">n</SB>are serially connected; and a circuit where n-stages of comb filters CO<SB POS="POST">1</SB>-CO<SB POS="POST">n</SB>are serially connected, is the filter for performing the downsampling of an input signal when the input signal is added to the first integrator IN<SB POS="POST">1</SB>. The CIC filter includes: a switcher 11 to which the outputs of the n-stages of integrators IN<SB POS="POST">1</SB>-IN<SB POS="POST">n</SB>are connected and which selectively transmits one of the outputs based on stage number information; a thinning circuit 12 for thinning a signal from the switcher 11, based on information expressing a rate conversion ratio, and adding the thinned signal to the first comb filter; a switcher 13 to which the outputs of the n-stages of comb filters CO<SB POS="POST">1</SB>-CO<SB POS="POST">n</SB>are connected and which selects one of the outputs, based on stage number information, so as to define the output as an output signal; and a controller 16 for transmitting the stage number information expressing the stage numbers of the integrators and the comb filters to the switchers 11, 13 and transmitting information expressing the rate conversion ratio for downsampling to the thinning circuit 12. <P>COPYRIGHT: (C)2012,JPO&INPIT |
