VIDEO SYNC SEPARATOR

A video signal is coupled by an emitter-follower through a capacitor to the base of a transistor connected in a common emitter configuration with its emitter directly connected to a clamping potential. A potential representing the average magnitude of the video signal is developed by an average detector and coupled to one input of a comparator circuit, a second input of which is connected to the clamping potential. Variations in the average magnitude of the video signal causes variations in a control signal developed by the comparator circuit, which control signal is utilized to vary the amount of current delivered to the plate of the coupling capacitor which is directly connected to the clamping transistor. With the time constant of the average detector set equal to at least one video frame interval, larger currents are provided to the coupling capacitor for larger video signals thereby permitting a wide variation in the magnitude of the video signals that may be coupled to the sync separator.