| 摘要 |
PURPOSE:To ensure the automatic correction for the display distortion by writing into the nonvolatile memory the deflecting current waveform which gives the coincidence between the pickup signal of the cross hatch chart and the cross hatch chart signal produced electrically and then giving the correction based on the written current. CONSTITUTION:Cross hatch chart 2 is picked up, and at the same time the cross hatch signal is produced electrically based on the horizontal and vertical driving pulses. And the difference is obtained through differential amplifier 25 between the both signals. Then the horizontal/vertical current waveforms are digitized via A/D converters 17 and 30 when no signal exists through cancelling on monitor TV26, and then written into nonvolatile memories 18 and 31. The horizontal deflecting current of memory 18 is read out in the same clock as that of the writing time and then turned into the saw-tooth wave through D/A converter 19 and LPF20 to be compared at comparator 21 with the deflecting current sent from resistance 9 via switch S2. And the difference, if any, is eliminated through the feedback via driving circuit 22 and saturable reactor 8. For the vertical deflection, the error signal is also fed back through saturable reactor 36 and in accordance with the output of comparator 34. |
