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File:John Logie Baird and television receiver.jpg

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Summary

Description
English: Scottish television pioneer John Logie Baird (left) and his television receiver. This was one of the world's first television systems, with which Baird demonstrated transmission of moving images in 1925. The transmitter consisted of a spinning disk with 30 lenses in it which focused light from a spot on the image onto a selenium photoelectric cell. As each lens swept across the subject the photocell produced an electric signal which varied with the brightness of the subject at each point along the scan line. In the television receiver shown here, the video signal from the transmitter is applied to a neon lamp behind another spinning disk with holes in it. As each hole sweeps in front of the lamp it reproduces a line of the image. Baird, left, holds a control with which he adjusts the speed of the disk to synchronize it with the transmitter disk. The reproduced image, visible at right was a dim orange, composed of 30 scan lines, just enough to recognise faces.

Because human faces did not have enough contrast to show up well, Baird used ventriloquist dummies in his first demonstrations, making them move and talk for the camera. The image shows his partner with two dummies on his lap. The television image shown was probably retouched in this photo.

Caption: "THE PICTURE THAT THE OBSERVER ACTUALLY SEES - This scene inside the receiving studio shows how the radioed living picture actually appears. The operator is holding the two dolls on his lap in much the same manner as the illustration on page 650. A loudspeaker located in the same cabined reproduces the voices at the same time."
Date
Source Retrieved August 15, 2014 from Orrin Dunlap, Jr., "The Televisor" in Popular Radio magazine, published by Popular Radio, Inc., New York, Vol. 10, No. 7, November 1926, p. 668 on AmericanRadioHistory.com.
Author Orrin Dunlap, Jr.
Permission
(Reusing this file)
This 1926 issue of Popular Radio magazine would have the copyright renewed in 1954. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. [1] Search of the Renewals for Periodicals for 1953, 1954, and 1956 show no renewal entries for Popular Radio. Therefore the magazine's copyright was not renewed and it is in the public domain.
Other versions The transmitter that produced this image is shown in John Logie Baird and Stooky Bill.png

Licensing

Public domain
This work is in the public domain because it was published in the United States between 1929 and 1963, and although there may or may not have been a copyright notice, the copyright was not renewed. For further explanation, see Commons:Hirtle chart and the copyright renewal logs.

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Public domain
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.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:John_Logie_Baird_and_television_receiver.jpg

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November 1926Gregorian

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current07:42, 19 August 2014Thumbnail for version as of 07:42, 19 August 2014683 × 762 (88 KB)ChetvornoUser created page with UploadWizard

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