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has been superseded by more modern filter designs, it remains the basis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...)
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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published, using material from an unpublished manuscript that she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>
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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>
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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>