THE DEVELOPMENT OF TELEVISION

After the end of the war, on both sides of the Atlantic, the possibility of development continued to be discussed, and around the world researchers were working towards financially-viable systems for television. These pioneers included John Logie Baird in England, Manfred von Ardenne in Germany, Edouard Belin in France, C. Francis Jenkins, Vladimir Zworykin and Ernst Alexanderson in the USA to mention only a few.

The development work at General Electric was led by Ernst Alexanderson. Then, as in earlier times, communication via letters between the different departments within General Electric was usual. In the collection of preserved documentation, which Alexanderson donated to the university library in his home town of Schenectady, there exist parts of the discussions about how to proceed with the development of the new technology. Alexanderson and his co-workers examined new designs, and after tests at the laboratory, a completed television receiver was developed for home use.

NIPKOW DISCS VERSUS MIRROR DRUMS.
The apparatus that was used at this time is entirely different from transmitters and receivers of today. The transmitters and receivers gradually came to have a number of components of pretty much the same kind, such as a strong light source, a lens system, a rotary perforated disk or mirror drum, microphone, amplifiers for sound and picture signal and an antenna system on the transmitting side. On the receiving side, the picture signals were received over an antenna to an amplifier and converted to feed a neon lamp. The light from the lamp passed through a perforated disk or a mirror drum of the same kind as at the transmitter and this was adjusted to rotate at the same speed as the transmitter’s disk. The resulting variation in light intensity was projected as a line pattern on a piece of cloth or paper display and after magnification, the picture reached the eye of the spectator. The technology which Alexanderson used can be studied in contemporary general outlines of his television system.

In January 1928 Alexanderson was ready to start demonstrations with the new receiver designed by General Electric for home use. Here follows a description of his first impressions by the eye witness G.C.B. Rowe in Radio News under the headline “Television enters the home.”