| 摘要 |
PURPOSE:To eliminate a shift in TV screen between both L and E systems and also to reproduce a correct picture without providing a switching method, by providing an integrating circuit for fly-back pulses with a switching transistor and discharging resistance. CONSTITUTION:When a horizontal synchronizing signal is applied, switch 8 turns on to put differential amplifiers 1 and 2 into operation. Then when fly-back pulse F is applied to the base of transistor TR19 of the integrating circuit, capacitor C13 is charged from electric power source 11 by way of TR17 and resistance 18. As pulse F is ceased, the accumulated charge of C13 is discharged via resistance 19 because of TR17 turns off to obtain saw-tooth waveform (b) having the upper clipped and the waveform is applied to the base of amplifier 2 as a comparison waveform, so that the outputs of differential amplifiers will be supplied to horizontal oscillating circuit 15 via filter 14. In this case, a phase comparison to the horizontal synchronizing signal is made on the basis of the mean value of the saw-tooth waveform, so that no shift in screen between both E and L systems will be made. |
