Video signal enhancement circuit

The enhancement circuit shown in the figure can increase the high frequency component of the video signal, thereby enhancing the contrast of the TV image. It can also be connected between the output of the video recorder and the SCART input of the TV. The transistor Tl in the circuit acts as a buffer. The resistor Rl ensures that the input impedance of the enhancement circuit is about 75Ω. The signal is added to the amplifier stage T2, and its gain depends on the position of the potentiometer P2. The frequency characteristics of the base signal of T2 are restricted by Pl, R6, and C6, so it can be controlled by the user to a certain extent (through Pl). The buffer stage T3 provides enough current to properly drive most 75Ω loads. Adjust the potentiometer P2 to make the output 1Vp-p (for open-circuit output, the level should be 2Vp-p).