File:Early Television System Diagram.png
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Summary[edit]
| Description |
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). |
| Date | |
| Source | Scanned from C. G. B. Rowe, "Television Comes to the Home" in Radio News magazine, published by Experimenter Publishing, New York, NY, Volume 9, Number 10, April 1928, p. 1098. The page numbers were on an annual basis, not per issue. This issue had pages 1089 to 1192. |
| Author | C.G.B. Rowe |
| Permission (Reusing this file) |
The copyright for this 1928 issue of Radio News would have to be renewed in 1955. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. http://onlinebooks.library.upenn.edu/cce/ A search of the Renewals for Periodicals from 1954 to 1957 shows no renewal entries for Radio News. The copyright on the magazine was not renewed and it is in the public domain. |
| Other versions | Image:Radio News Apr 1928 pg1100.png |
Licensing[edit]
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This work is in the public domain in the United States because it was published (or registered with the U.S. Copyright Office) before January 1, 1929.
 Public domain works must be out of copyright in both the United States and in the source country of the work in order to be hosted on the Commons. If the work is not a U.S. work, the file must have an additional copyright tag indicating the copyright status in the source country.
Note: This tag should not be used for sound recordings. |
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
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| current | 04:20, 7 August 2008 | | 1,152 × 630 (371 KB) | Swtpc6800 (talk | contribs) | == Summary == {{Information | Description= Television Comes to the Home ''Radio News'', April 1928. Volume 9 Number 10. :Published by Experimenter Publishing, New York, NY :Editor-in-Chief and Publisher: Hugo Gernsback *[[:Image:Radio News Apr 1928 pg |
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