| 摘要 |
PURPOSE:To increase degree of circuit integration by detecting a characteristic change of a picture tube from an anode current of the picture tube and adjusting automatically the characteristic change of each picture tube depending on the detection so as to eliminate the need for re-adjustment at a secular change of a picture tube and reducing number of external connection terminals. CONSTITUTION:One terminal of the secondary coil of a flyback transformer is connected to common via a resistor R and a capacitor C1, a voltage drop of the resistor R1 is a characteristic detection signal of a picture tube 41, and a DC detection signal Vc is obtained via a differentiation circuit comprising R2, C2, an amplifier 44, a diode D1 and a capacitor C3. When an R-Y color difference signal is fed from a chrominance circuit 22 to a bias circuit 23, a switch 33 is thrown to the position to supply the detection signal Vc to a line l11 synchronously with an output signal of a counter circuit 32. Similarly, the detection signal Vc is fed to a line l12 at the supply of a G-Y signal and the detection signal Vc is fed to a line l13 at the supply of a B-Y signal. The circuit operation is executed as above, resulting that bias adjustment in response to an individual characteristic of the picture tube 41 is attained automatically.
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