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Article: Not the usual channels; Coding theory.(Transmitting information reliably)
- Article from:
- The Economist (US)
- Article date:
- July 3, 2004
CopyrightCOPYRIGHT 2004 Economist Newspaper Ltd. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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How to transmit information reliably
ON JULY 1st, a spacecraft called Cassini went into orbit around Saturn--the first probe to visit the planet since 1981. While the rockets that got it there are surely impressive, just as impressive, and much neglected, is the communications technology that will allow it to transmit its pictures millions of kilometres back to Earth with antennae that use little more power than a light-bulb.
To perform this transmission through the noisy vacuum of space, Cassini employs what are known as error-correcting codes. These contain internal tricks that allow the receiver to determine whether what has been received is accurate ...