| 摘要 |
PURPOSE:To prevent the generation of a black frame or pictures at the fringe part of a positive picture, by performing binary coding to the undesired part of an analog signal such as the part of an analog picture signal corresponding to the fringe part outside a range showing the desired picture information in comparison with a fixed level value such as a signal which is turned into black after the binary coding. CONSTITUTION:The clock signals of picture element periods which are supplied from an oscillator 15 are counted, and the picture signal is coded to binary number. In this case, a changeover switch 13 is connected to the side of a comparing voltage source 14 by the count output until the sampling output voltage V3 supplied from a sample holding circuit 3 corresponds to the 34th picture element. Then the comparing voltage Vref is supplied to an input terminal of a differential amplifier 5, and the difference output voltage between the voltage V3 and the voltage Vref is coded to binary number. The binary coding is carried out to the picture elements following the 34th one by connecting the switch 13 to the side of a delay element 4. |
