Valdemar Poulsen ( dates Valdemar Poulsen , November 23, 1869 , Copenhagen - July 23, 1942 ) - Danish engineer . He developed a method of magnetic recording on a wire in 1898 .
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| Awards and prizes | US National Inventors Hall of Fame |
The principle of magnetic recording was demonstrated by Poulsen in early 1898 . The first device was called a telegraph and used a metal (steel) wire as a carrier. Modern tape recorders use more convenient and reliable magnetic tapes , but the basic principle of analog sound recording has not changed: the signal is fed from the amplifier to the recording head along which the medium (tape or wire) moves at a constant speed, as a result of which the medium is magnetized according to the sound signal. When reproducing sound, the medium at the same speed stretches along the reproducing head, inducing a weak electrical signal in it, which, after amplification, is fed to the loudspeaker .
Poulsen received a telegraph patent in 1898 . There were no sound amplifiers then, so the sound was very weak and could be listened to only with headphones. In 1908, Poulsen developed an improved version of the arc transmitter named after him. He died at the 73rd year of his life in New York , USA . In 1969, a postage stamp was issued in honor of Poulsen.
Telegraph Poulsen
U.S. Patent Pulsen for Magnetic Wire Recorder
Notes
- ↑ Encyclopædia Britannica
- ↑ 1 2 SNAC - 2010.
Links
- " 1898 - 1998 Poulsen's patent ." 100 years of magnetic recording.
- Katz, Eugenii, " Biography ." Biosensors & Bioelectronics.
- Poulsen, Valdemar, " US Patent 661,619 Method of Recordings and Reproducing Sounds or Signals ." Magnetic Tape Recorder.
- 1900 World Exposition recording of Emperor Franz Joseph of Austria by means of Poulsen's telegraphone.