| 摘要 |
PURPOSE:To attain binary discrimination of a picture signal without using a light shield plate and a special amplifier, by differentiating an analog picture signal, comparing and discriminating the signal, frequency-dividing it into two and obtaining exclusive OR of the frequency dividing signal. CONSTITUTION:The analog picture signal from a reading element 2 is amplified at an amplifier 3, differentiated at a differentiating circuit 5, inputted to comparators 6, 7 and compared and discriminated in the positive and negative direction at a prescribed slice level. An output of the comparators 6, 7 is applied to flip-flops 9, 10, where the output is frequency-divided into two. The signal divided into two is inputted to an exclsive OR 11 to obtain a digital picture signal. |
