| 摘要 |
PURPOSE:To give a stable DC bias to a video signal amplifier circuit by providing a constant current circuit as a DC regenerating means and constituting an output amplifer so as to be operated under an ideal condition in order to amplify an video signal with fidelity. CONSTITUTION:The video signal Vi inputted from a terminal 1 is inputted to a base of a transistor(TR) Q3 via a capacitor C1. A constant current circuit 12 comprising a TR Q4 and resistor R7, R9 is connected to an emitter of the TR Q3. Further, a resistor R8 and a capacitor C2 deciding an AC gain are connected in series between the emitter of the TR Q3 and ground. Aload resistor RL is connected to the collector of the TR Q3 and its output signal is led to a cathode of a cathode-ray tube 11. Moreover, resistors R5, R6 are connected between the collector of the TR Q3 and ground, a divided output signal obtained from its connecting point enters a sampling gate 4 while being sampled during the back porch period. A capacitor 9 for holding gives one potential of an error amplifer 6. |
