| 摘要 |
PROBLEM TO BE SOLVED: To realize an A/D converter including a high-resolution and low-noise noise elimination function. SOLUTION: A clamp means 102 eliminates the input fluctuation of a non-signal level, and a sample/hold means 106 stores the output voltage of an amplifier 104. When the reference signal of a stepwise signal exceeds an input signal level, the output of an amplifier 107 is inverted. A higher-order digital value is determined in this timing, and the sample/hold means 106 stores the output voltage of an amplifier 103. The reference signal is then changed with the amplitude of a stepwise voltage of the stepped wave. When the voltage change in the reference signal is amplified by the amplifier 103 and exceeds the hold voltage of the sample/hold means 106, the output of the amplifier 107 is inverted and a lower-order digital value is determined. An A/D conversion value is synthesized from the higher-order and lower-order digital values. The number of times of voltage comparison can be decreased even with high resolution and noise reduction is made possible by narrowing an analog signal bandwidth. COPYRIGHT: (C)2005,JPO&NCIPI
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