An AGC circuit comprises a video IF amplifier for receiving a amplitude-modulated broadcast wave of a video signal with a signal level having a constant amplitude added thereto, a means connected to the output of said amplifier for generating a video detection output signal of said broadcast wave, and...http://www.google.es/patents/US4234892?utm_source=gb-gplus-sharePatente US4234892 - AGC Circuit responsive to intermediate gray level in video signal
AGC Circuit responsive to intermediate gray level in video signal
