| 摘要 |
PURPOSE:To digitally detect a bit of flicker information by a simple circuit constitution by providing a logarithmic amplifier applying logarithmic compression to a light receiving output by an optical sensor and a D flipflop receiving the logarithmic amplifier output as a data input. CONSTITUTION:Outputs of logarithmic amplifiers 3, 4 are subtracted by a differential amplifier 6 and a logarithmic ratio (logR/B) is calculated, a white balance adjusting circuit 7 controls the amplification gain of AMP10, 12 of R, B signals obtained by an optical lens 8 and an image pickup element 9 and the white balance adjustment is realized at an times so that the mean level ratio of the R, G, B signals being outputs of AMP 10-12 is 1:1:1. The output of the logarithmic amplifier 5 is inputted to the amplifier 13 and amplified to a TTL level and fed to a data input terminal D of the D flip-flop 14. A vertical synchronizing signal from a synchronizing signal generating circuit 15 is inputted to a clock input terminal and its output is subjected to peak rectifier by a peak rectifying circuit 17 via a differentiation circuit 16 and the result is outputted as a flicker detection signal at an output terminal 18. |
