| 摘要 |
PURPOSE:To improve the reproducibility of a characteristic test by adjusting the off-setting voltage of a staircase-wise wave signal added to a measuring object A/D converter. CONSTITUTION:At the time of the characteristic test of a measuring object A/D converter 2, the output voltage of a direct current voltage generating device 6 is added to a staircase-wise wave signal generated by a video signal generating device 1 with an adder 7 and the off-setting voltage is changed. The converter 2 samples the voltage with the clock of a clock generating device 5 and converts it to a digital signal. A D/A converter 3 converts this digital signal to an analog signal and adds it to a video signal measuring instrument 4. The measuring instrument 4 executes the measurement of a differential phase and a differential gain for respective off-setting voltages, and records the measured value in respective off-setting voltages together with an off-setting voltage set value. Thus, by executing the characteristic test of the converter 2, the mutual relation of the off-setting voltage set value and the differential phase and the differential gain concerning the converter 2 is cleared, the influence of the quantizing error due to the change of the off-setting voltage can be removed and the reproducibility of the characteristic test can be increased.
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