Multiple channel TV remote monitoring system - uses coder and modulator for each camera and decoder and demodulator for each screen

摘要

The method of monitoring remote positions using television cameras for traffic control etc., uses a coding device for each camera each followed by a modulator for connections to a common transmission line. At the receiving point, after passing through intermediate amplifiers, the signals pass through a demodulator for each monitoring screen. A decoding device for each demodulator can give a digital coded signal from the demodulated video signal. The coding device has a summing amplifier between the input and output, and the input is also connected to a preamplifier and two amplitude filters. These are interconnected with an AND-gate and counter for counting the image free hold signals and a decoder and multiplexer which generate a coded bit pattern for feeding back to the summing amplifier.