| 摘要 |
PURPOSE:To remove the bright lines occurring in a cathode current detection signal as these bright lines appear in the upper part of a screen of the CRT display and disturb the screen display in the case of the underscan display at the time of inserting the above-mentioned detection signal in vertical fly-back time, detecting the cathode current corresponding to this signal and subjecting this current to negative feedback control so as to maintain the specified current. CONSTITUTION:A current for local overscan is passed to an auxiliary deflection coil 20' via an auxiliary deflection circuit 21 at the timing at which the cathode current detection signal is inserted in the vertical fly-back time from a pulse signal generating section 22, by which the bright line disturbance appearing in the upper part of the screen is erased. |
