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A '''Welch-Costas array''' is a [[Costas_array|Costas array]] generated using the following method.
A '''Welch-Costas array''' is a [[Costas array|Costas array]] generated using the following method.


We take a primitive element, alpha, of a prime, p. We raise alpha to successive powers, modulo p. This creates a Costas permutation of length p-1.
We take a primitive element, alpha, of a prime, p. We raise alpha to successive powers, modulo p. This creates a Costas permutation of length p-1.

Revision as of 19:37, 25 May 2006

A Welch-Costas array is a Costas array generated using the following method.

We take a primitive element, alpha, of a prime, p. We raise alpha to successive powers, modulo p. This creates a Costas permutation of length p-1.

Example: 2 is a primitive element of 5. 3^1 = 3 3^2 = 9 = 4 (mod 5) 3^3 = 27 = 2 (mod 5) 3^4 = 81 = 1 (mod 5)

[3 4 2 1] is a Costas permutation.