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This programme investigates the importance of digital communication in contexts ranging from a dramatic rescue at sea to a long-distance consultation between a specialist doctor and a pregnant patient. Computer graphics and extracts from the 1999 Faraday Lecture help to unravel the physical principles behind all this, and reveal the importance of binary code, multiplexing and noise reduction to ensure the successful transfer of information.
Introduction to the digital world.
The dramatic story of a life-threatening capsizing in remote Antarctic waters during a round-the-world yacht race in 1998. Mayday call from capsized boat via communications satellite to rescue centre in Australia. Position of boat determined via the satellite; mayday alert sent by email and satellite to laptop computer on board only vessel in same region: another race competitor. How satellite can deal with many messages at once. Successful rescue of yachtsman. Digital communications essential to safety at sea. New lightweight, energy-efficient equipment creates opportunities for round-the-world racers to conduct live television interviews and maintain websites from the confined cabins of their racing boats. Mobile phones that allow anyone on the move to access the Internet and send and receive live video.
Demonstrations and graphics explain some of the underlying principles of digital communication. The binary code, and how it can be carried by electrical currents, radio and light waves. Demonstration of the use of multiplexing to combine two messages, send them along the same carrier, and separate them at the receiving end.
The use of digital imaging and multiplexing to allow a specialist doctor in London to not only talk to a pregnant patient on the Isle of Wight but also view live ultrasound images of the baby in the womb.
Demonstrations and graphics explain the idea of noise the random low-level background voltage which can contaminate electronic communications. How noise can be removed from digital information, and why it is much more difficult to remove from analogue information. Digital signals from deep space: the importance of removing noise from signals sent back from deep-space probes such as Galileo.
How supermarkets rely on digital information held in bar codes for pricing, charging and restocking.
The crucial importance of communications technology for a young man with cerebral palsy who, like Stephen Hawking, uses computer equipment and software to communicate with the people around him.
Summing up, and a brief preview of the next programme.