Abstract: An apparatus and method is provided wherein a television signal being traitted may be modified by multiplexing in a digital information-bearing signal in a manner that binary pulses are encoded upon horizontal synchronizing pulse windows contained within the composite video signal. The apparatus comprises two primary subsystems, an encoder and a decoder. The encoder is further composed of four components (1) a horizontal synchronous pulse detector, (2) a pulse position modulator, (3) a digital signal conditioner, and (4) a mixer. The decoder consists of three components: (1) a horizontal synchronizing detector, (2) a pulse position demodulator, and (3) a digital signal conditioner. Functionally, the video/digital data multiplexer is a pulse position (PPM) digital communication system which utilizes the leading edge of the horizontal synchronizing pulses of a composite video signal as a marker denoting the location where a pulse will be inserted.

Abstract: This invention improves on explosively actuated cable cutters in that it orporates a remote capability of activating the cutter. The improved apparatus comprises an acoustical transducer for receiving a remote coded signal, an electric circuit designed to detect the specific coded signal, a motor and gear mechanism which is initiated upon detection of the remote coded signal to activate the explosively actuated cable cutter.The electronics and motor compartment are hydrostatically sealed and pitted with a pressure switch and a water intrusion fail-safe circuit. The pressure switch is designed to inactivate the apparatus beyond a preset ocean depth, and the water intrusion fail-safe circuit is designed to detect any seawater seepage into the sealed electronics compartment. Upon the detection of such seepage the intrusion fail-safe circuit disconnects the system from the battery thereby removing danger of premature triggering of the cable cutter.