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The Fast Walsh-Hadamard Transform and Processors by Using Delay Lines

Mikio NAKATSUYAMA, Norio NISHIZUKA

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Summary :

The algorithm for the fast Walsh-Hadamard transform (FWT) derived from the Walsh-Paley function provides fast and simple processors which calculate the i-th Walsh transform Fi (i0, 1, , 2n1) of the natural-, dyadic-, and sequency-ordered Walsh-Hadamard transforms respectively according to control signals. This processor needs only 2・2n1 adder-subtractors (A/S) and is n times as fast as the one of the iterative type with n iterations. The characteristics of FWT with the term T resemble that of the assembly of digital filters. The digital filter representing FWT can be analyzed with z-transform and its transfer function is described as a simple function of z. The 3 dB bandwidth calculated by FWT is almost constant (about 0.85/T) for n2, 3, ...,10. All the Walsh transform Fi can be calculated by the processor with n・2n A/S, while the processor using delay lines needs only 2・2n1 A/S. The improved processor with delay lines deals with successive data and calculates all the Walsh transform or the Walsh spectrograms at the same time. These processors are effective for the recognition of speech and the analysis of signals.

Publication
IEICE TRANSACTIONS on transactions Vol.E64-E No.11 pp.708-715
Publication Date
1981/11/25
Publicized
Online ISSN
DOI
Type of Manuscript
PAPER
Category
Data Processing

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