Experimental television receiver

The beginnings of television. The first ‘radiovision’ broadcasts were made twice a week from the École Supérieure des PTT, created in 1933 under the directorship of René Barthélemy, head of the Compagnie des Compteurs’ Experimental Television Centre at Montrouge. At the École Supérieure d’Électricité in Malakoff in April 1931, Barthélemy organised the first demonstration of television in France. He had devised a synchronised electromechanical procedure based on the analysis and reproduction of the image by line-by-line and point-by-point scanning using a Nipkow disc. Light variations are transformed into electrical current by photoelectric cells. The image is then transmitted by electromagnetic waves. Barthélemy developed his procedure, improving image definition from 30 to 60 then 180 lines. But this electromechanical system soon reached its limits, and the development of cathode-ray tubes and electronic image analysers opened the way for television’s commercial exploitation.