| 摘要 |
PURPOSE:To obtain the accurate waveform of a correction signal through simple constitution by measuring the level, etc., of the correction signal with a signal from a photodetector. CONSTITUTION:A horizontal and a vertical deflection signal from a deflecting circuit 1 are supplied to the deflection coil 3 of a picture tube 2. Then, part of the vertical deflection signal is supplied to a parabolic wave generating circuit 4, a parabolic wave signal Sa from which is supplied to a deflection coil 5 for correction. This parabolic wave signal Sa is supplied to a two-phenomenon oscilloscope 6. Further, a detection signal Sb from a photodetector 7 is supplied to the oscilloscope 6 through an attenuator 8. So as a point where the photodetector 7 is in contact is an accurate landing state, the parabolic wave generating circuit 4 is adjusted and the level B at the intersection of the rising signal Sb and signal Sa is read to measure the necessary amount of correction at the point. Further, the distance l from the beginning of the parabolic signal Sa to the rising point of the signal Sb is measured to obtain the accurate position of a measurement point on the deflection signal. |
