| 摘要 |
PURPOSE:To binary-code correctly a complicated analog picture signal by providing each circuit detecting the leading and trailing of an analog signal and a detecting circuit detecting respectively the increase and decrease from the 1st and 2nd reference values. CONSTITUTION:When the analog signal A falls down rapidly, a differentiating circuit 1 outputs a negative differentiating waveform and when a value of a leading detecting circuit 2 exceeds a prescribed voltage Vb, an output of a trailing detecting circuit 3 goes to 1, is inputted to a set terminals S of an RS FF14 and becomes an output 1. When the analog signal A rises rapidly conversely, the differentiating circuit outputs a positive differentiating waveform and an output 0 is obtained. Further, the analog signal A is changed continuously from a white level to a black level for a half tone changed continuously and when the level is decreased from the 2nd reference value, an output signal of a decrease detection circuit 11 goes to 1 and becomes an output 1 by being added to the RS FF14 via an OR circuit 12.
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