| 摘要 |
An apparatus for converting an analog image signal to a digital image signal based on a reference voltage, includes a counter having a control terminal, for counting a first signal and outputting a counted value in digital form, a D/A converter for converting the counted value to an analog voltage signal served as the reference voltage, an A/D converter for converting the analog image signal to the digital image signal based on the reference voltage generated by the D/A converter, and a comparator for comparing in magnitude the digital image signal and a threshold level used for limiting the magnitude of the digital image signal, thereby outputting a control signal based on the results of comparison. The counter continues to count the first signal until the control signal derived from the comparator is supplied to the control terminal of the counter.
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