Administration and Logistics
Please contact the technical staff before shipping instruments or standards to the address listed below.
National Institute of Standards and Technology
Boulder, CO 80305-3328
|Service ID Number||Description of Services||Fee($)|
|77110S||Characterization of Atomic Frequency Standards||At Cost|
|77120S||Characterization of Oscillators:Time Domain||At Cost|
Fees are subject to change without notice.
An atomic standard is characterized by comparing it against UTC (NIST). This characterization test determines the long-term performance of the standard in the time domain and requires 30 days of measurements. The 5-MHz output of the standard is sampled every 720 seconds and it is compared with the 5-MHz UTC (NIST) signal using the NIST time scale measurement system. The square root of the Allan deviation σ y (τ) is computed to 2 x 10-15, which is the frequency stability of UTC (NIST) for averaging times longer than 1 day. The fractional frequency drift of UTC (NIST) is less than 2 x 10-16 per day. The offset between UTC (NIST) and TAI used to determine the uncertainty of this calibration is conservatively set at 10-14. The actual values transferable to the standard are often limited by the standard's own stability and noise properties.
NIST provides services to characterize the short-term performance, in the time domain, of frequency sources with a frequency of 5 MHz. The 5-MHz output of the source under test is sampled at 1s intervals and compared with the 5-MHz UTC (NIST) signal. The stability in terms of the square root of the Allan deviation σ y (τ) is then computed and to 4 x 10-13/T1/2 for averaging times up to 10,000 s. The frequency offset is measured with a relative standard uncertainty of 10-14, limited by the offset between UTC (NIST) and TAI used to determine the uncertainty of this calibration. The actual values transferable to the frequency source under test are often limited by the source's own stability and noise properties.
References—Calibration and Characterization of Oscillators and Amplifiers
Introduction to the Time Domain Characterization of Frequency Standards, J. Jesperson, Proc. 25th Annu. Precise Time and Time Interval (PTTI) Meeting, Pasadena, CA, 83-102 (Dec. 1991).
An Introduction to Frequency Standards, L. Lewis, Proc. IEEE 79 (7), 927-935 (July 1991).
Properties of Signal Sources and Measurement Methods, D. A. Howe, D. W. Allan, and J. A. Barnes, in Characterization of Clocks and Oscillators, edited by D. B. Sullivan, D. W. Allan, D. A. Howe, and F. L. Walls, Natl. Inst. Stand. Technol. Tech. Note 1337, 14-16 (1990).
Characterization of Clocks and Oscillators, D. B. Sullivan, D. W. Allan, D. A. Howe, and F. L. Walls, eds., NIST Tech. Note 1337 (Mar. 1990).
Frequency and Time-Their Measurement and Characterization, S. R. Stein, Precision Frequency Control, Vol. 2, edited by E. A. Gerber and A. Ballato (Academic Press, NY), 191–232 (1985).