error correcting code

Definition: Information in a data stream or signal used to ensure the original message can to be decoded without degradation or errors in the decoding. * The code (a) checks for basic errors (e.g. sum of all terms should be a positive integer) and if it detects an error it (b) calls for re-transmission or re-reading of data or (c) indicates an error. * For CDs, cross-interleaved Reed-Solomon code is used. * May be called error detecting codes.
Redundant errors
In a sense, the error correcting code is redundant data in the information stream since its absence does not lead directly to loss of data. But such codes are vital for reliable communications: with digital files, a single misplaced term could render billions of other terms an indecipherable heap of code.

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