| 摘要 |
PURPOSE:To ensure the optimum conversion of signals with no overflow by changing the quantizing level of an A/D converter in response to the gain control signal when an analog signal underwent the gain control is converted into a digital signal by an A/D converter. CONSTITUTION:The analog video signal underwent the gain control by a gain controller 9 is converted into a digital signal by an A/D converter 13. In this case, the reference voltage of the converter 13 is changed by the control signal of the controller 9. thus the quantizing level of the converter 13 is changed. As a result, the level of the input signal is limited within a high dynamic range of the converter 13. This attains the optimum A/D conversion of signals with no overflow.
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