| 摘要 |
PROBLEM TO BE SOLVED: To provide a delta-sigma A/D converter in which the number of comparators in a sub A/D converter is reduced, without deteriorating noise performance. SOLUTION: The delta-sigma AD converter is provided with a loop filter 4, the sub A/D converter 5, and a sub D/A converter 7 so as to execute sampling for each period. The sub A/D converter 5 is provided with first/second A/D converters 8, 10, a decoder 11 for coupling digital signals outputted from the first/second A/D converters 8, 10, and a first D/A converter 9 for converting the digital signals outputted from the first A/D converter 8 to analog signals. A difference between analog signals, which are converted by the first D/A converter 9 from the digital signals converted by the first A/D converter 8 from the analog signals outputted from the loop filter 4, and analog signals, inputted to the second A/D converter 10, is inputted to the second AD converter 10. A delay amount from the first A/D converter 8 to the second A/D converter 10 is set so as to be less than one period. COPYRIGHT: (C)2007,JPO&INPIT
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