A Monolithic Wideband Synchronous Video Detector for Color TV

This paper describes a low-level detector intended primarily for video IF detection in TV sets and designed specifically for integrated circuit fabrication. The device is a detector for amplitude modulated signals with up to 100% modulation, giving a low distortion high level, wideband output for small input signals. The detection is full-wave synchronous, or doubly-balanced, giving rejection of carrier components in the input signal. When used as a TV video IF detector, where the carrier frequency is in the 40-50 MHz range, the unwanted products of detection are high enough in frequency to be lost in the internal capacitance of the device, with the output comprising only the wanted video signal. A built-in suppression of chroma-sound intercarrier beat greatly eases the sound trapping requirements. The principle behind the device is not new, but the integrated circuit structure used is novel and has many advantages over a discrete approach.