| 摘要 |
<P>PROBLEM TO BE SOLVED: To upgrade the sensitivity of a receiver as a whole by enhancing an S/N in a reception signal band even if signals different in center frequency are received. Ž<P>SOLUTION: A band pass delta/sigma A/D converter includes: an integration circuit 2 for integrating a differential signal outputted from a subtractor 1; a quantizer 3 for quantizing the differential signal integrated by the integration circuit 2; a D/A converter 4 for converting the quantized signal outputted from the quantizer 3 into an analog signal; and a differentiation circuit 5 for differentiating the analog signal outputted from the D/A converter 4 and outputting a result of the differentiation to the subtractor 1 as a feedback signal. A switching circuit 7 switches a resonant frequency of a resonance circuit 6 constituted of the integration circuit 2 and the differentiation circuit 5. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
|
