Costas JohnP

American electrical engineer who invented, among other things, the Costas loop and Costas arrays. The Costas loop is a modified phase locked loop that recovers the "suppressed" carrier in many digital communications receivers. In the 1960s, he helped solve the mystery concerning poor performance of sonar systems. He found that the rapidly time-varying channel made coherent processing inappropriate. His solution involved a kind of permutation array, now known as a Costas array, which has ideal properties for the problem. He died on 9 August 2008, aged 84. Link to Wikipedia biography Read less