four-aspect signal
71Gramophone record — A 12 inch (30 cm) 33⅓ rpm record (left), a 7 inch 45 rpm record (right), and a CD (above) A gramophone record, commonly known as a phonograph record (in American English), vinyl record (in reference to vinyl, the material most commonly used after …
72Laserdisc — Not to be confused with disk laser, a flat configuration solid state laser. Not to be confused with VCD, DVD, or Blu ray, optical disc formats employing digital video encoding. Not to be confused with CED, a coincident but incompatible analogue… …
73Mathematics and Physical Sciences — ▪ 2003 Introduction Mathematics Mathematics in 2002 was marked by two discoveries in number theory. The first may have practical implications; the second satisfied a 150 year old curiosity. Computer scientist Manindra Agrawal of the… …
74Ethology — Not to be confused with ethnology. Animal Behavior redirects here. For the journal, see Animal Behaviour (journal). For the Praxis single, see Transmutation (Mutatis Mutandis). Part of a series on …
75Phase-shift keying — Passband modulation v · d · e Analog modulation AM · …
76Cryptanalysis of the Enigma — enabled the western Allies in World War II to read substantial amounts of secret Morse coded radio communications of the Axis powers that had been enciphered using Enigma machines. This yielded military intelligence which, along with that from… …
77ProHD — State of the Industry = The U.S. consumer appetite for high definition television (HDTV) programming is undeniable. The Consumer Electronics Association says that more than 50 percent of U.S. households now own a digital television. It is… …
78Media and Publishing — ▪ 2007 Introduction The Frankfurt Book Fair enjoyed a record number of exhibitors, and the distribution of free newspapers surged. TV broadcasters experimented with ways of engaging their audience via the Internet; mobile TV grew; magazine… …
79Latin American dance — Introduction dance traditions of Mexico, Central America, and the portions of South America and the Caribbean colonized by the Spanish and the Portuguese. These traditions reflect the distinctive mixtures of indigenous (Amerindian), African, and …
80Consolidated B-24 Liberator — B 24 redirects here. For other meanings, see B24 (disambiguation). B 24 Liberator U.S. Army Air Forces Consolidated B 24D Liberator over Maxwell Field, Alabama …
