| 摘要 |
PURPOSE:To enable extremely accurate centering by obtaining a relative error signal of a picture center position from the output signal of each image pickup tube and by converting its magnitude into a counter count value. CONSTITUTION:For position on the basis of green image pickup tube 1, video output G' is passed through delay lines 4 and 11 to main line signal G0 and also supplied to differential amplifier 6 via delay lines 4 and 5 to output edge signal EDG. Either one of video outputs R0 and B0 is applied to differential amplifier 15 together with signal G0 to obtain positionshift signal REG. Those signals EDG and REG are supplied to multiplier 9 for multiplication to generate signal ER of a horizontal error from the center position. This signal ER is compared by the comparator, whose output is converted into the count value of the up-down counter. Then when there are a prescribe number of sampling gate signals SG or more from gate signal generator 10, an accurate error signal is assumed to be obtained by sufficient sampling data so the picture center position is adjusted. |
