File:Early NBS crystal oscillator frequency standards.jpg
Early_NBS_crystal_oscillator_frequency_standards.jpg (700 × 395 pixels, file size: 66 KB, MIME type: image/jpeg)
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DescriptionEarly NBS crystal oscillator frequency standards.jpg |
English: Four precision 100 kHz quartz crystal oscillators maintained by the US Bureau of Standards (now the National Institute of Standards and Technology that served as the frequency standard for the United States in 1929. Built by Bell Telephone Laboratories, where the quartz crystal oscillator was invented in 1923, they achieved a frequency stability of 10-7. The oscillators are enclosed in temperature controlled ovens kept at a precisely constant temperature to prevent thermal expansion and contraction of the quartz resonator, which would cause changes in frequency. The large crystal resonators are mounted under the glass domes visible on top of the units. |
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Author | Unknown authorUnknown author |
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Public domainPublic domainfalsefalse |
This image is in the public domain in the United States because it is a work of the United States Federal Government, specifically an employee of the National Institute of Standards and Technology, under the terms of Title 17, Chapter 1, Section 105 of the US Code.
English ∙ 日本語 ∙ македонски ∙ Nederlands ∙ +/− |
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current | 18:12, 3 September 2013 | 700 × 395 (66 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
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