Valdemar Poulsen
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Valdemar Poulsen (1869 - 1942) was a Danish engineer. In 1899, he developed a magnetic tape recorder.
The magnetic recording was demonstrated in principle as early as 1898 by Valdemar Poulsen in his telegraphone. Magnetic wire recording, and its successor, magnetic tape recording, involve the use of a magnetizable medium which moves with a constant speed past a recording head. An electrical signal, which is analogous to the sound that is to be recorded, is fed to the recording head, inducing a pattern of magnetization similar to the signal. A playback head can then pick up the changes in magnetic field from the tape and convert it into an electrical signal.
Poulsen obtained a Telegraphone Patent in 1898. Poulsen developed an Arc Converter in 1908, referred to as the "Poulsen Arc Transmitter". A stamp was issued in honor of Poulsen in 1969.
See also
External links
- "1898 - 1998 Poulsen's patent (http://www.amps.net/newsletters/issue27/27_poulsen.htm)". 100 years of magnetic recording.
- Katz, Eugenii, "Valdemar Poulsen (http://www.geocities.com/neveyaakov/electro_science/poulsen.html)". Biosensors & Bioelectronics.
- Poulsen, Valdemar, "US661619 Method of Recordings and Reproducing Sounds or Signals (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=661619.WKU.&OS=PN/661619&RS=PN/661619)". Magnetic Tape Recorder.da:Valdemar Poulsen