Colour television camera with integrators - uses integrators to control black reference level of each colour together with lineariser and reference voltage

摘要

The colour televison camera produces a video signal from each image tube, each signal contg. a black reference level which is adjusted as a function of the average image luminance. For a particular colour component the image passes through the objective lens, a colour-filter separation unit and onto the faceplate(19) of an image tube(16). Part of the scanned image is kept at reference black(20), resulting in a black reference level in the video signal. After amplification(23) and linearisation(24) the video signal is output(26). An integrator(33) taps this output, passes the average luminance level in the video signal to a lineariser(38) for comparison(44) with a reference voltage before being used, synchronised by the image tube scan signal(55), to adjust the black reference signal(32).