D-c coupled sync clipping video amplifier

Claim 1

In a DC coupled television receiver responsive to composite television signals including video signal components extending over a predetermined useful range of magnitudes and synchronizing signal components having magnitudes outside the predetermined useful range of the video signal components, the television receiver having a circuit for removing the synchronizing signal components including in combination: a video signal transistor amplifier stage including a transistor having input, output, and common terminals; means for supplying the composite video signal, including the video signal components and the synchronizing signal components, to the input terminal of the transistor; means for supplying operating potential to the output terminal of the transistor; voltage responsive switch means coupled in circuit between the common terminal of the transistor and a point of reference potential, the switch means being normally nonconductive and being rendered conductive in response to signals applied thereto having a magnitude in excess of a predetermined threshold, the threshold being such that the magnitudes of the synchronizing signal components are insufficient to render the switch means conductive, with the switch means being rendered conductive in response to composite video signal components within said predetermined range; and the switch means being connected in the primary signal path of the transistor amplifier stage, so that amplification of signals thereby is substantially prevented until the switch means is rendered conductive.