## Time and Frequency Measurements## Characterization of Oscillators and Amplifiers
Stefania Romisch Trudi Peppler
Fees are subject to change without notice.back to top of page | back to index of time and frequency measurements ## Oscillator Frequency Calibration (77100C)NIST provides calibration services for oscillators with an output frequency of 1 Hz to 50 GHz. The relative standard uncertainty is nominally that of the NIST frequency standard, which is 5 x 10 back to top of page | back to index of time and frequency measurements ## Characterization of Atomic Frequency Standards (77110C)An atomic standard NIST characterizes by introducing it as a member of the NIST time scale system. The output of the standard is sampled every 2 h in sequence with the other clocks in the time scale, and the performance of the standard under test is readily determined. The standard test involves 30 d of measurements. The square root of the Allan variance τ) is measured to 3 x 10^{-15}, for averaging times of 7200 s to 10^{6} s. The relative standard uncertainty of the time scale is 5 x 10^{-15} and the fractional frequency drift is less than 2 x 10^{-16} per day. The actual values transferable to the standard are often limited by the oscillator's stability and noise properties.back to top of page | back to index of time and frequency measurements ## Characterization of Oscillators: Time Domain (77120C)NIST provides services to calibrate oscillator frequencies of 5 MHz, 10 MHz, and 100 MHz. The stability in terms of the square root of the Allan deviation τ) is determined by repeated measurements at 0.5 s intervals σ (_{y}τ) is determined to 4 x 10^{-13}/t^{-1/2} for averaging times of 0.5 s to 10 000 s and frequency offset is measured with a relative standard uncertainty of 5 x 10^{-15}, limited by the noise level and type in the oscillator under test. The frequency measurement transferable to the oscillator is often limited by the oscillator's stability due to transport between laboratories and on-off cycling. Measurements of Allan deviation from approximately 1 µs to 0.5 s can be determined by integration of the oscillator phase noise. This inversion of the data is performed by NIST. Thus, measurements in this range should be done under Service ID Numbers 77130C or 77140S. Characterization of time domain stability at other frequencies is covered under Service ID Number 77140S.back to top of page | back to index of time and frequency measurements ## Characterization of Oscillators and Amplifiers: Phase Noise in the Frequency Domain (77130C)NIST provides calibration services of the phase noise of single oscillators and amplifiers. For frequencies of 5 MHz to 26 GHz, phase modulation (PM) noise ^{2} /Hz. At a carrier frequency of 5 MHz, S can be measured to -145 dB for a frequency offset of 1 Hz and -190 dB for an offset of 10 kHz. At a carrier frequency of 100 MHz, _{φ}(ƒ)Scan be measured to -50 dB for a frequency offset of 1 Hz and -190 dB for an offset of 50 kHz. A typical value of standard uncertainty is 1 dB, but specific values depend on the carrier frequency and the offset frequency. Specific measurement requirements should be discussed prior to placing an order. PM noise for frequencies above this range (but less than 110 GHz) are covered under Service ID Number 77140S._{φ}(ƒ)back to top of page | back to index of time and frequency measurements ## Characterization of Oscillators and Amplifiers: Amplitude Noise in the Frequency Domain (77131C)NIST provides calibration services of amplitude noise of single oscillators and amplifiers. For frequencies from 1 MHz to 26 GHz, amplitude modulation (AM) noise S can be measured to -140 dB for a frequency offset of 1 Hz, and -180 dB for an offset of 10 kHz. At a carrier frequency of 100 MHz, _{α}(ƒ)S can be measured to -30 dB for a frequency offset of 1 Hz and -180 dB for an offset of 50 kHz. A typical value of standard uncertainty is 1 dB, but specific values depend on the carrier frequency and the offset frequency. Specific measurement requirements should be discussed prior to placing an order. AM noise for frequencies above this range (but less than 110 GHz) are covered under Service ID Number 77140S._{α}(ƒ)back to top of page | back to index of time and frequency measurements ## References—Calibration and Characterization of Oscillators and AmplifiersIntroduction 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 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). back to top of page | back to index of time and frequency measurements |