Valdemar Poulsen

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Valdemar Poulsen (1869–1942)

Valdemar Poulsen (born November 23, 1869 in Copenhagen , † June 23, 1942 in Gentofte near Copenhagen) was a Danish physicist , inventor and engineer . In the first decade of the 20th century he achieved the world's first wireless transmission of sounds with his arc transmitter , just like RA Fessenden with a machine transmitter, which was a pioneering achievement both for radio technology and for the development of radio .

Life

Valdemar Poulsen was the son of Jonas Nicolai Johannes Poulsen (1836–1914), a judge at Højesteret and later head of the Ministry of Justice from his first marriage to Rebekka Magdalena nee. Brandt (1848–1873) was born. In school he showed a great interest in physics, chemistry and drawing from an early age. Math was not his great strength, however. He attended Borgerdydskole in Christianshavn until 1889 and then studied philosophy and medicine at the University of Copenhagen , preferring to attend Julius Thomsen's lectures in chemistry and not obtain an academic degree. At the Polyteknisk Læreanstalt he failed the entrance exam in mathematics. He then worked at the mask factory Frich's Efterfølgere in Århus until he got a job as a test engineer at the Copenhagen Telephone Company (KTAS) in Copenhagen in 1893 . During this time he developed a special interest in the recording of sound waves , which he later explained by saying that he was dissatisfied with the fact that a caller could not leave a message if the person called could not be reached.

The telegraphone

Drawing of the magnetic recorder for U.S. Patent 661,619
Telegraphon around 1898 (in Brede works Industriemuseum, Lingby)

By the end of November 1898, Poulsen constructed the world's first functional device for recording and reproducing sound waves via electromagnetic induction . At first he called his invention a telephonograph . However, the French engineer Jules Ernest Othon Kumberg already claimed this artificial concept of telephone and phonograph . Hence, Poulsen eventually used the name telegraphon . On December 1, he applied for a patent in Denmark and then in the German Reich and in numerous other countries. After he had received the German patent on December 10, 1898, but before the decision of the patent office in Denmark, he had already quit his employment and founded the Aktieselskabet Telegrafonen Patent Poulsen with the support of investors . Peder Oluf Pedersen, who later became the rector of Polyteknisk Læreanstalt, was one of the engineers who were subsequently hired for his company, with whom he soon received further patents for improvements to his invention. The board of directors of his young stock corporation, chaired by Lemvig Fog, believed that a strong partner was needed to successfully bring the telegraph onto the market. Poulsen therefore reached an agreement with Mix & Genest , a German manufacturer of telephones that he already knew as a supplier to his former employer KTAS. The majority of his new employees moved from Copenhagen to Berlin to the Mix & Genest research laboratory in the winter of 1899 .

Other inventors had also previously considered a magnetic recording method. The Frenchman Paul Janet wrote a work in 1887 with the title Transverse Magnetization of a Conductor in which he first described in general the possibility of sound recording with a wire. Oberlin Smith in the United States submitted a patent caveat , a kind of advance application, to the American patent office on October 4, 1878 , and published his specific ideas for implementation in a letter to the editor, which was printed on September 29, 1888 in the magazine The Electrical World . Instead of a solid wire, he wanted to use a cotton or silk thread with woven metal shavings for recording, because he was afraid that the magnetization would spread uncontrollably in a wire. It is not known whether Smith attempted to construct a working model for his idea. When he heard about Poulsen's Telegraphon in the newspaper in 1900 and wanted to claim retrospective protection from the US Patent Office for the method he had invented in 1878, he was too late.

Poulsen presented a revised version of his telegraphone to an enthusiastic public at the Paris World Exhibition of 1900 in the Palais de l'Electricité and won a Grand Prix , which was awarded for the best invention. Wilhelm Exner , Director of the Technological Trade Museum in Vienna and as General Commissioner of the Austrian Department for Paris on site, immediately acquired a copy on behalf of the Ministry of Commerce. A year later it was exhibited with other Austrian acquisitions for four weeks in the Gustav Pisko art salon in Vienna and presented to Franz Joseph I , Emperor of Austria-Hungary on October 12, 1901 . Poulsen had arrived from Copenhagen in good time and was supported in the presentation by two representatives from Siemens & Halske , which had meanwhile acquired the production rights for the German Empire, Austria-Hungary and the Russian Empire . The 24-second recording of the Emperor's voice that was made during the demonstration is now the oldest magnetic sound recording that has survived.

Poulsen had already parted ways with Mix & Genest in August 1900 , who did start production but did not want to provide any financial support for the further development of his invention. In April 1902, the new partner Siemens & Halske also got out again, pointing out that there would be no way of improving the volume, which was far too low, in the foreseeable future. The search for investors in the United States, which Poulsen had begun after the World's Fair, dragged on with unsuccessful negotiations. After an agreement in 1903, he founded the American Telegraphone Company in Maine and gave it his American patent rights. However, the company was unable to raise the funds for the planned construction of a production facility. In 1905, stockbroker Charles Funkenhauser persuaded the Danes to undertake a management buy-out . Business in the Danish parent company was also subdued. Although an improved model could record up to 30 minutes at a time with a steel wire running speed of 2.13 m per second, demand was limited. The attempt to record on a steel disc with a diameter of about 13 cm, similar to a vinyl record , instead of on steel wire , led to a device with which only about two minutes of recording were possible on each side of the disc, a multiple of this compared to alternative recording methods such as the phonograph cost. Therefore, only about 100 of them were built.

The arc transmitter

a Poulsen arc transmitter

In 1903 Poulsen invented the arc transmitter to generate undamped vibrations. Because of their constant frequency and amplitude, these are suitable as carrier oscillation for modulation with speech or sound signals. In 1904 Valdemar Poulsen succeeded in establishing a voice connection by radio for the first time . In 1906 the mature technology was published. It forms the basis for today's radio and radio technology. After the world's first successful wireless voice transmission, Poulsen also succeeded in 1907 in bridging the Atlantic with voice signals.

family

In 1894, Poulsen married Frederikke Marie Rasmussen (1868–1921); two years later his son, the future geologist Christian Henrik Otto Poulsen (1896–1975), was born in Frederiksberg . After his wife died on July 24, 1921, Poulsen married Asta Stoltz Nielsen (1899–1974) in 1923.

Services

  • Telegraphone for sound recording
  • Ticker for the recipient
  • Arc transmitter for sound transmission

See also

Web links

Individual evidence

  1. ↑ Eric D. Daniel, C. Denis Mee, Mark H. Clark: Magnetic Recording - The First 100 Years . IEEE Press, New York 1999, ISBN 0-7803-4709-9 . P. 15.
    ( limited preview in Google Book search)
  2. ^ The Telephonograph . In: New Science , Vol 12, No. 308, 23 November 1900, p. 812 f.
  3. ↑ Procedure for receiving and temporarily storing messages, signals or the like , German Imperial Patent No. 109569 of December 10, 1898
  4. ↑ cf. Method of recording and reproducing sounds or signals , U.S. Patent No. 661,619 of November 13, 1900. In: freepatentsonline.com, accessed November 7, 2015
  5. ↑ Eric D. Daniel, C. Denis Mee, Mark H. Clark: Magnetic Recording - The First 100 Years . IEEE Press, New York 1999, ISBN 0-7803-4709-9 . P. 17.
    ( limited preview in Google Book search)
  6. ↑ Elisabeth Antébi: Die Elektronik Epoche , Springer Basel 1982, ISBN 3-0348-6741-7 , p. 161
    restricted preview in the Google book search
  7. ↑ Valdemar Poulsen . In: Encyclopædia Britannica Online, accessed November 6, 2015
  8. ^ Hanns Günther : Wave telegraphy. A radio technical internship. Franckh'sche Verlagshandlung, Stuttgart 1921, p. 72.
  9. ^ Wireless over Atlantic. In: The New York Times . July 28, 1907.
personal data
SURNAME Poulsen, Valdemar
BRIEF DESCRIPTION Danish physicist and engineer
DATE OF BIRTH November 23, 1869
PLACE OF BIRTH Copenhagen
DATE OF DEATH June 23, 1942
Place of death Gentofte