Hadamard code: Difference between revisions

Revision as of 10:15, 7 June 2018

Revision as of 22:48, 31 July 2018

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The Hadamard code is based on Hadamard matrices, and while there are many different Hadamard matrices that could be used here, normally only [[Hadamard matrix#Sylvester's construction|Sylvester's construction of Hadamard matrices]] is used to obtain the codewords of the Hadamard code.

[[James Joseph Sylvester]] developed his construction of Hadamard matrices in 1867, which actually predates Hadamard's work on Hadamard matrices. Hence the name ''Hadamard code'' is not undisputeddisputed and sometimes the code is called ''Walsh code'', honoring the American mathematician [[Joseph Leonard Walsh]].

A Hadamard code was used during the 1971 [[Mariner 9]] mission to correct for picture transmission errors. The data words used during this mission were 6 bits long, which represented 64 [[grayscale]] values.