Video signal stabilization

An apparatus for stabilizing an unmodulated video signal that has a sync tip voltage includes an amplifier for amplifying the video signal according to a control voltage, a transistor receiving the amplified video signal from the amplifier on the base of the transistor and outputting the amplified video signal on the collector, a sync tip voltage detector connected to the emitter of the transistor for detecting the sync tip voltage in the video signal and outputting a voltage derived from the sync tip voltage, an integrator having three inputs, one of which is the voltage derived from the sync tip voltage and another of which is a reference voltage and an output to the amplifier as the control voltage, a stabilization loop including a low current detector that detects low current levels in the amplified video signal through an optical coupler to a resistive element and a pulse stretcher that outputs a signal to the third input of the integrator, whereby the sync tip voltage detector, integrator and amplifier cooperate to stabilize the video signal in most circumstances, and the stabilization loop prevents video signal voltage from increasing to too high a level for the sync tip voltage detector.