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Title: Large symmetric. pi. transformations for Hadamard transforms

Journal Article · · Appl. Opt.; (United States)
DOI:https://doi.org/10.1364/AO.22.000826· OSTI ID:6029620

Many multiplexing instruments utilize the fast Hadamard transform (FHT) to demultiplex the signal. In the past, the HFT includes the ..pi../sub 1/ and ..pi../sub 2/ transformations to reorder vectors before and after a Sylvester-type Hadamard transform. Although the computational effort involved in the ..pi../sub 1/ and the Sylvester-type Hadamard transform scales as n log/sub 2/n, calculating the ..pi../sub 2/ transformation (which only has to be done once) scales as n/sup 2/. Recently Gunson (1980) has suggested a method by which the ..pi.. transformations are symmetric, that is ..pi../sub 2/ = ..pi../sub 1/. We have calculated a complete set of symmetric ..pi.. transformations for FHT of sizes 2/sup 3/ to 2/sup 30/. Special emphasis has been placed on the phase of the ..pi.. transformation so as to have the correct phase in the demultiplexed signal.

Research Organization:
University of California, Los Alamos National Laboratory, Los Alamos, New Mexico 97545
OSTI ID:
6029620
Journal Information:
Appl. Opt.; (United States), Vol. 22:6
Country of Publication:
United States
Language:
English