| 摘要 |
PURPOSE:To enable to reduce the power consumption of deflection circuit, by controlling the passage of deflection wave signal through the use of gate circuit, when the range of search toward specific direction is increased. CONSTITUTION:In the deflector which deflects the electron beam of the Braun tube 5 is spiral or concentrically, the spiral sweep of the deflection wave voltage generation circuits 6, 7 of X and Y axes and the time serial operation of the time serial circuit 3 are made by the synchronizing circuit 16, and each deflection wave voltage of the deflection wave voltage generation circuits 6, 7 is respectively fed to the multiplication circuits 17, 18 for the delivery of squared voltage, and each squared voltage is added at the addition circuit 19. The output voltage of the addition circuit 19 is fed to the comparison circuit 20, and it is compared with the set voltage of the reference voltage set circuit 21, and when the distance to the sweeping position of electron beam is greater than the redius of displayed screen, the comparison circuit 20 delivers the output voltage, enabling the erase of luminance of electron beam with the electron beam positioned at the center position of the displayed screen. |
