Hadamard code: Difference between revisions

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Errors of up to 7 bits per word could be corrected using this scheme. Compared to a 5-[[repetition code]], the error correcting properties of this Hadamard code are much better, yet its rate is comparable. The efficient decoding algorithm was an important factor in the decision to use this code.
 
The circuitry used was called the "Green Machine". It employed the [[fast Fourier transform]] which can increase the decoding speed by a factor of three. Since the 1990s use of this code by space programs has more or less ceased, and the [[NASA Deep Space Network]] does not support this error correction scheme for its dishes that are greater than 26 m.
 
==Constructions==