Transmission system for the transmission of analog image - and synchronizing signals and the course of mixer synchronous numerical data signals by means of analog lines

摘要

A video composite transmission system connecting a camera and a picture receiver of a picture transmitting device and a plurality of data terminals to a video switching network via an analog two path line transmitting an analog video composite signal. In the transmission part, it comprises means for shortening pulses of blanking and synchronizing the signal transmitted from the camera and thereby obtaining a blanking and synchronizing signal, in elongated back blanking porches of which are integrated and companded first digital multiplex data channels transmitted from first data terminals. Second digital multiplex data channels are also integrated and companded into the trace interval of each available black line of vertical blanking and synchronizing signal transmitted from camera. The first and second digital multiplex companded data channels are mixed and converted in a multilevel code, and the multilevel coded channel is analogically mixed with the shortened blanking and synchronizing signal and the whole of video signal to obtain said analog video composite signal. The receiving part of the system enables each initial digital data channel and the initial blanking and synchronizing signal to be reconstituted in response to the analog composite video signal transmitted from video switching network.