GB1306083A - - Google Patents

Abstract

1306083 Remote control of T.V. cameras EMI Ltd 5 May 1970 [9 May 1969] 23656/69 Heading G4H Control signals to an underwater T.V. camera are transmitted over the conductor carrying the returning camera video signal during either line or field blanking periods of the video signal. The control signals are superimposed on a D.C. power signal which is transmitted either continuously or only with the control signals. In the arrangement of Fig. 1, switches SW1 and SW2 in the camera and surface receiver, respectively, in a first position pass video signals from a camera terminal 3 over a coaxial cable 12 to a video output terminal 4. Timing generators 8 and 7 detect line, or alternatively field blanking periods in the video signal and change the two switches to a second position so connecting a control signal transmitter 1 over the cable 12 to a receiver 2. Variable control potentials controlling, for example, pan, tilt and focus of the camera, are applied to terminals 14-16 and produce for each control a serial pair of amplitude significant pulses, the pulses of a pair being of equal and opposite amplitude, which are superimposed upon a D.C. power signal. The respective pairs may be transmitted one after another in a predetermined sequence during a single field blank period. Alternatively the pair of each control may be sent once during each of a group of successive line blank periods, one control after another in successive groups.