| 摘要 |
PURPOSE:To stably adjust gain of a gain control circuit which is made into LSI on digital copying devices provided with scanners. CONSTITUTION:An A/D conversion output of an analog signal processing circuit 10 for digitalizing an analog signal from a CCD line sensor 5 at the time of reading a white reference board is outputted to CPU through a buffer 30b in a picture signal control circuit 30. CPU decides the optimum gain from the output and a present gain set value, and it is inputted to LSI 10 through a buffer 30c. Thus, the gain can stably be controlled by adjusting the input level of the analog signal which is to be A/D-converted from the outside of LSI 10. |
