| 摘要 |
PURPOSE:To satisfy with one pin of an IC by adding a blanking signal and a character signal in an addition circuit, supplying to a separating circuit in the IC and supplying respectively the separated blanking signal to a blanking circuit and the character signal to the addition circuit. CONSTITUTION:The blanking signal Sb from a character generator 11 and the character signal Sc are added in the addition circuit 14. When a signal Sa is supplied to the separating circuit 6 through an input terminal of the IC2, namely the pin 15, a transistor 28a is turned on and 28b is turned off and in an output terminal 31, the potential Sd of a power source terminal 20 is obtained. Since the potential of the input terminal 15 is higher than a base potential E1 of a transistor 21b, a transistor 21a is conductive, a transistor 23 is turned off, the transistors 21b and 21a constitute a differential amplifier and signals Se and Sf of a reversed polarity are obtained in output terminals 24a and 24b. Then, the signal Sd is supplied to the blanking circuit 5, the blanking is applied to a video signal, and the signal Sf or Se is supplied to the addition circuit 7 to perform a character display.
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