| 摘要 |
PURPOSE:To secure the extraction of the steady correction current waveform regardless of some variation of the horizontal pulse duration by modulating the saw- tooth wave of the horizontal period via the saw-tooth wave signal of the vertical period, at the same time securing an assured correction for the keystone distortion. CONSTITUTION:The left-half of the vertical saw-tooth wave is applied to the base of transistor Tr16, and the negative horizontal pulse is applied to the base of Tr25. Thus Tr25 is turned on and then turned off when no negative horizontal pulse is applied. In other words, in the positive left half of the vertical saw-tooth wave voltage, the waveform applied to the base of Tr16 is shwon in the left-half of c; while the waveform applied to the base of Tr16 in the reverse mode is shown in the right-half of c respectively. This waveform c is steady just with a slight reduction of the L1 width as shown by dotted line A even though the pulse duration of the horizontal pulse has some fluctuation. At the same time, vertical saw-tooth wave d is applied to the emitter of Tr16, and add-up wave e is delivered to output terminal 20. |
