| 摘要 |
PURPOSE:To eliminate the periodical noises of an A/D converter by providing a noise memory to store the noise signal of the output of the A/D converter in a state where no input signal exists. CONSTITUTION:An A/D converter 10 delivers the periodical noises in a state where the converter 10 has no input, and the periodical noises are stored in a noise memory 12. While the converter 10 delivers a digital signal containing the noise component when the converter 10 has an input signal. The output signal of the converter 10 is supplied to a subtractor circuit 14 together with the periodical noise read out of the memory 12. Then the subtraction processing is carried out. Thus the periodical noises can be eliminated for the converter 10. |
