Valdemar Poulsen

Valdemar Poulsen ( born November 23, 1869 in Copenhagen, † June 23, 1942 in Gentofte near Copenhagen) was a Danish physicist, inventor and engineer. He succeeded in the first decade of the 20th century, with its arc transmitter, as well as RA Fessenden with a machine station, the world's first wireless transmission of voice, which both of the two was a pioneering achievement for the wireless technology such as the development of radio.

Life

Born in 1869, Denmark was the inventor of Telegraphons. He not only created a device that is with the help of electromagnetic induction in a position to record sound waves and then reproduce, he founded with his invention and the Magnetic. The telegraphone is therefore the forerunner of all tape recorders and tape recorders. In the 40s and 50s reached the direct development of Telegraphons, the Drahttongerät, a certain distribution.

Poulsen registered his patent for the telegraphone 1898. A revised version of his invention, he presented at the Paris World Exhibition of 1900 and won the Grand Prix with this, a prize that was awarded to the best invention. At the Paris World Exhibition Poulsen took on the voice of the Emperor Franz Joseph of Austria - Hungary; the recording is still preserved.

The telegraphone consisting essentially of a steel strip or wire, which is passed to an electromagnet. When recording of the electromagnet is connected to a microphone, which converts the received sound waves into alternating voltages. Thus, the electromagnet is magnetized and magnetically by the running steel strip.

To play the microphone must be replaced by a speaker. The previously magnetized tape is now gone out again on the electromagnet. Because the magnetic field of the steel strip at each location is not equally strong, a current flows in the solenoid coil of the speaker is generated. Thus, the diaphragm is connected to the coil begins to oscillate and the previously Captured is now heard again.

1903 invented the Poulsen arc transmitter for generating undamped oscillations. This technique was a prerequisite for a narrow-band transmission wave, which was required for the modulation voice or audio signals. 1904 Valdemar Poulsen succeeded for the first time, a voice connection over the radio. 1906, the mature technology has been published. This forms the basis for the current radio and wireless technology. Just as the world's first successful signal transmission in the form of language, managed Poulsen 1907, the first bridging of the Atlantic with speech signals.

List of most important inventions

• Telegraphone to record sound
• Scores for the receiver
• Arc transmitter to transmit sound