Otto Julius Zobel (1887–1970) was a design engineer who worked for the American Telephone & Telegraph Company (AT&T) in the early part of the 20th century. Zobel's work on filter design was revolutionary and led, in conjunction with the work of John R. Carson, to significant commercial advances for AT&T in the field of frequency division multiplex (FDM) telephone transmissions. Although much of Zobel's work has been superseded by more modern filter designs, it remains the basis of filter theory and his papers are still referenced today. Zobel invented the m-derived filter and the constant-resistance filter, which remains in use. Zobel and Carson helped to establish the nature of noise in electric circuits, concluding that—contrary to mainstream belief—it is not even theoretically possible to filter out noise entirely and that noise will always be a limiting factor in what it is possible to transmit. Thus, they anticipated the later work of Claude Shannon, who showed how the theoretical information rate of a channel is related to the noise of the channel. (more...)
Recently featured: Nebula Science Fiction – Australian Cattle Dog – Warkworth Castle Archive – By email – More featured articles... Read the rest of this article: <http://en.wikipedia.org/wiki/Otto_Julius_Zobel> _______________________________ Today's selected anniversaries: 98: Trajan, namesake of a forum, a market and a column in Rome, succeeded his adoptive father Nerva as Roman emperor. <http://en.wikipedia.org/wiki/Trajan> 1813: The novel Pride and Prejudice by English author Jane Austen was published, using material from an unpublished manuscript that she originally wrote between 1796 and 1797. <http://en.wikipedia.org/wiki/Pride_and_Prejudice> 1933: Choudhry Rahmat Ali published a pamphlet entitled "Now or Never" in which he called for the creation of a Muslim state in northwest India that he termed "Pakstan". <http://en.wikipedia.org/wiki/Choudhry_Rahmat_Ali> 1964: An unarmed US Air Force T-39 Sabreliner on a training mission was shot down over Erfurt, East Germany, by a Soviet MiG-19, killing all three aboard. <http://en.wikipedia.org/wiki/1964_T-39_shootdown_incident> 1984: Tropical Storm Domoina made landfall in southern Mozambique, causing some of the most severe flooding so far recorded in the region. <http://en.wikipedia.org/wiki/Tropical_Storm_Domoina> _____________________________ Wiktionary's word of the day: stoically (adv): 1. In a manner that endures pain and hardship without outwardly showing suffering or expressing complaint. 2. In an unfeeling manner that inwardly is unaffected by pain or distress <http://en.wiktionary.org/wiki/stoically> ___________________________ Wikiquote quote of the day: Perhaps the only misplaced curiosity is that which persists in trying to find out here, on this side of death, what lies beyond the grave. --Colette <http://en.wikiquote.org/wiki/Colette> _______________________________________________ Wikipedia Daily Article mailing list. To unsubscribe, visit: https://lists.wikimedia.org/mailman/listinfo/daily-article-l Questions or comments? Contact [email protected]
