Kinescope driver apparatus with contrast enhancement

Amplifier apparatus, comprising:

• an inverting amplifier having an input terminal for receiving a video input signal to be amplified, having an output terminal for providing an amplified video output signal and having linear and non-linear feedback paths;
• said two feedback paths together determining a nominal closed loop gain for the amplifier;
• said non-linear path including both amplitude and frequency dependent elements and comprising a circuit node coupled via first and second resistors to respective ones of said input and output terminals of said amplifier and including a voltage dependent impedance, a frequency dependent impedance and a source of reference potential coupled in circuit with said node for modifying said closed loop gain of said amplifier;
• characterized in that;
• for driving a kinescope, said output terminal of said amplifier is coupled to a cathode electrode of a kinescope;
• said frequency dependent impedance and said voltage dependent impedance are coupled in parallel between said circuit node and said source of reference potential;
• the values of said frequency dependent impedance, said voltage dependent impedance, said first and second resistors and said source of reference potential being selected for increasing the closed loop gain of said amplifier in low brightness picture areas and for increasing the closed loop gain of said amplifier for high frequency video detail signal components in high brightness picture areas to provide images on said kinescope having expanded low-light contrast and enhanced high-light picture detail.