| 摘要 |
PURPOSE:To simplify and rationalize a system and to attain a proper character signal display by suppling the primary color signals of red, green and blue of a character signal to an OR circuit and making an output signal thereof the control signal of a chrominance signal switching circuit constituting of a color video and the character signals. CONSTITUTION:The primary color signals of red, green and blue of the color video signal are inputted from input terminals 1-3 and supplied to the switching circuits 45-47. The primary color signals of red, green and blue of a screen displaying character signal are inputted from input terminals 6-8, amplified in amplifiers 51-53 and supplied to the switching circuits 45-47. The respective primary color signals of the character signal inputted from the input terminals 6-8 is also supplied to the OR circuit 55, OR processed and the switching control signals is formed. Accordingly, when the primary color signal is inputted to any one of the input terminals 6-8, the switching control signal is outputted from the OR circuit 55 and the switching circuits 45-47 are switched to the character signal side. Thereby, the processing means of the switching control signal is not required but circuit constitution is simplified.
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