Constrained codes
Information Theory Accomplishment | 1970
IBM researchers: Peter A. Franaszek
Where the work was done: IBM T.J. Watson Research Center
What we accomplished: Franaszek (pictured) is responsible for the theory and application of constrained channel coding, a process that transforms a variety of code strings so that they require less storage space or require less transmission time when sent over a communications link. These codes enforce constraints on the sequence of signals in order to limit interference, enable clock synchronization, and shape the signal spectrum. Constrained coding is widely used in digital recording and communications systems.
Related links: Sequence-state methods for run-length-limited coding [IBM Technical Journals]; Wikipedia entry.
Image credit: Computer Hope
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