| 摘要 |
A gain control circuit includes an automatic gain controller (AGC), an analog-to-digital converter (ADC), a saturation field detecting block, a sync detector and a gain control block. The AGC controls amplitude of an analog image signal including a luminance signal, a color signal and a sync signal. The ADC converts the amplitude-controlled analog image signal to a digital image signal. The saturation field detecting block determines on a per field basis whether the digital image signal is saturated. The sync detector is configured to detect the sync signal in the digital image signal. The gain control block provides a gain control signal to the AGC based on an output signal of the saturation field detecting block and an output signal of the sync detector. Therefore, the gain control circuit may prevent saturation of the analog image signal by controlling gain of the analog image signal.
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