| 摘要 |
PURPOSE:To prevent mis-reading by adding an analog delay circuit, an AND circuit and an OR circuit in addition to a peak hold circuit. CONSTITUTION:A sample-and-hold circuit 1 samples separately only a video signal from noise in an input signal IN and samples and holds it by a prescribed clock. A delay circuit 2 gives a prescribed time of delay to an analog signal A of the circuit 1 and outputs an analog signal B. An AND circuit 4 ANDs analogically the signals A, B. A peak hold circuit 3 follows a samll level of fluctuation of the peak value of the signal A and holds the peak value at large level fluctuation. An OR circuit 7 ORs analogically an output C of the circuit 3 and the signal A. A comparator 8 takes a value dividing an output E of the circuit 7 by a prescribed ratio as a reference compares an output F of the circuit 4 to binary-code. The ruggedness of the input signal is smoothed in the output F to include much black level component and to reduce noise due to dirt or the like. |
