ファイル:Early Television System Diagram.png - Wikipedia
- ️Sat Mar 10 1928
English: Diagram of an early mechanical-scan television system. This technology was used in the first experimental television broadcasting stations in the 1920s and 1930s, before it was replaced by modern electronic-scan television systems in the 1940s
The television camera (top left) uses a spinning disk with a spiral pattern of holes, called a Nipkow disk, to sweep a narrow beam of light in a raster pattern across the subject. The reflected light would be picked up by a photoelectric cell whose electrical output would vary with the intensity of the light. This system was often called a "flying spot scanner". The early photoelectric cells were not very sensitive so three or four would be used with the subject in a darkened booth.
The television receiver received the video signal produced by the camera's photoelectric cell, amplified it, and used it to drive a neon lamp. In front of the neon light was another Nipkow disk with the same hole-pattern as the camera, spinning synchronized at the same speed. Each hole passing in front of the neon lamp produced a scan line of the image. The varying video signal from the photoelectric cell varied the intensity of the neon lamp, producing the different The result was a small fuzzy monocolor orange picture about 1.5 inch square of the remote subject. Typical systems produced 25, 48, and 60 line images at frame rates of 15 and 20 frames per second.
Alterations to image: This page was scanned by User:Swtpc6800 on an Epson Perfection 1240U at 300 dpi with half-tone de-screening enabled and stored as TIFF. The image was touched up in Adobe Photo Elements 5.0 and this copy saved as a 150 dpi PNG. The magazine is 8.5 by 11.5 inches (23 by 29 cm).
