| 摘要 |
PURPOSE:To simplify the circuit-constitution and to reduce cost by switching between external R/G/B-signals and television R/G/B-signals by using at least one of the former signals to decrease the number of pins in integrating the circuits. CONSTITUTION:A brightness signal processing circuit 8 lets a brightness signal Y inputted from a terminal 15 pass freely during a time when no control signal is inputted from an OR circuit 7, but when this controlling signal is inputted, outputs a control signal to let matrix circuits 4-6 output only the external R/G/B-signals. Accordingly, if the said signals are inputted to either one of external-R/G/B-signal input terminals 12-14, they are inputted to the circuits 4-6 through switching circuits 1-3. In the mean time, a control signal is outputted from the OR circuit 7, and the such control signal as letting the circuits 4-6 output only the external R/G/B-signals is outputted from the circuit 8. Therefore, only the signals that are inputted to the input terminals 12-14 are outputted to R/G/B-output terminals 16-18.
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