| 摘要 |
PURPOSE:To continuously follow up the fluctuation of a vertical synchronizing signal frequency and to optimize vertical linearity by changing the correction of the vertical linearity corresponding to the frequency of an input vertical synchronizing signal. CONSTITUTION:This circuit is constituted of first and second capacitors C1 and C2, a frequency/voltage conversion part 1 for converting the frequency of the vertical synchronizing signal VD to a DC voltage, first and second resistors R1 and R2, a first current control circuit 2 composed of a first operational amplifier 3 and a first FET, etc., and a second current control circuit 4 composed of a second operational amplifier 5 and a second FET, etc. other than that basic charge and discharge by a ramp generator are applied to the first and second capacitors C1 and C2, charge and discharge by the resistor R1 and the circuit 2 are applied to the capacitor C1 and the charge and discharge by the resistor R2 and the circuit 4 are applied to the capacitor C2. Then, the charge and discharge currents of the circuits 2 and 4 are changed by the voltage corresponding to the vertical synchronizing signal frequency and the sawtooth waves of a required waveform are generated. |
