Video Enhancer

The enhancer amplifies the high frequencies of a video signal, resulting in a sharper picture. It may be inserted between, say, the video recorder output and the SCART input of television receiver.

The simple design is based on only three transistors. The first, T1, is a buffer. Resistor Rensures that input impedance of order of 75Ω. The signal is then applied to amplifier T2,  whose gain is determined by the setting of P2.

The frequency characteristics of a signal at the base of T2  is shaped by P1, R6, and Cand is, therefore, to a certain extent under the control of the user  (by P1). Buffer T3, provides sufficient current for correctly driving most 75Ω loads. Preset P2, must be set to give an output voltage of 1 Vpp (terminated output: for an open circuit output the level should be 2 Vpp).

The enhancer draws a current of about 50mA. Note that 12V supply should be regulated.

Video Enhancer Schematic diagram

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