File:Goldschmidt tone wheel.jpg
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DescriptionGoldschmidt tone wheel.jpg |
English: The Goldschmidt tone wheel, a rotary switch invented by German engineer Rudolf Goldschmidt used in early radio receivers for reception of radiotelegraphy (Morse code) signals. This device was used in RCA's transatlantic reception station at Tuckerton, New Jersey as a beat frequency oscillator to receive international telegram traffic. The device consisted of a commutator wheel with many contacts around the rim spun at a high speed by an electric motor, with a sliding spring contact. When connected to a current source the wheel broke the current many times per second, acting as a high frequency generator. The high frequency signal created by the wheel was mixed with the incoming Morse code signal, and created an audible beat frequency that was heard as a tone in the receiver's earphones ,making the pulses of carrier, the "dots" and "dashes" audible. This tone wheel rotated at 4000 RPM and produced a square wave signal of around 40 kHz. Tone wheels were used for a short time around World War 1, until they were replaced by vacuum tube beat frequency oscillators in the 1920s. Later tone wheels were used in electronic organs to generate audio |
Date | |
Source | Retrieved November 1, 2014 from Elmer Eustice Bucher (1917) Practical wireless telegraphy: A complete text book for students of radio communication, Wireless Press, New York, p. 286, fig. 299 on Google Books |
Author | Elmer Eustice Bucher |
Licensing[edit]
Public domainPublic domainfalsefalse |
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:Goldschmidt_tone_wheel.jpg |
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 15:49, 28 January 2022 | 1,137 × 834 (201 KB) | Thomas H. White (talk | contribs) | Somewhat better scan qaulity | |
18:38, 1 May 2021 | 1,034 × 743 (478 KB) | Materialscientist (talk | contribs) | FFT | ||
19:25, 1 November 2014 | 1,034 × 743 (252 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
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Horizontal resolution | 72 dpi |
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Software used | Adobe Photoshop Elements 2.0 |
File change date and time | 10:45, 28 January 2022 |
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