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Time and Frequency Measurements

PM/AM Noise Measurement Systems

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Technical Contact:
David Howe
Tel: 303-497-3277
E-mail: dhowe@boulder.nist.gov

Trudi Peppler
Administration and Logistics
Tel: 303-497-3338
Fax: 303-497-6461
E-mail: tpeppler@boulder.nist.gov

Please contact the technical staff before shipping instruments or standards to the address listed below.

Mailing Address:
National Institute of Standards and Technology
M.C. 847.30
325 Broadway
Boulder, CO 80305-3328

Service ID
Number
Description of Services Fee($)
77135C Tests of RF PM/AM Noise Measurement Systems: On-Site Tests At Cost
77140S Special Time/Frequency Measurements: Oscillators and Other Components At Cost

Fees are subject to change without notice.

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Tests of RF PM/AM Noise Measurement Systems: On Site Tests (77135C)

NIST provides an on-site calibration service of the accuracy of phase modulation (PM) noise and amplitude modulation (AM) noise and noise floor of the measurement systems at the customer's site by use of two separate portable PM/AM secondary noise standards. One noise standard is for carrier frequencies of 5 MHz, 10 MHz, and 100 MHz, designated as model 510100 and the other for carrier frequencies of 10 GHz, 20 GHz and 40 GHz, designated as model 102040. The first PM/AM noise standard (Model – 510100) produces two output signals at 5 MHz, 10 MHz, and 100 MHz carrier frequencies with approximately +10 dBm to +15 dBm. For these three carrier frequencies, the residual double sideband PM noise [Sφ(ƒ)] between the two outputs is typically less than -187 dBrad2/Hz for a Fourier frequency offset from the carrier of 100 kHz. The calibrated PM or AM noise is typically constant with Fourier frequency offset to +0.1 dB out to 3 % of the carrier frequency. 
The second PM/AM noise standard (Model – 102040) also produces two output signals at 10 GHz, 20 GHz, and 40 GHz carrier frequencies with approximately +10 dBm. The residual PM noise, Sφ(ƒ) between the two outputs is typically less than -187 dBrad2/Hz for frequency offsets of 1 MHz and above from the carrier frequency. The calibrated PM or AM noise is typically constant with Fourier frequency offset to +0.2 dB out to 100 MHz. The noise standard at alternative frequencies such as 10.6 GHz, 21.2 GHz, 42.4 GHz is also available.

After each calibration, NIST issues a calibration report for the customer's measurement system at the frequencies tested.

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Special Time/Frequency Measurements: Oscillators and Other Components (77140S)

NIST provides calibration services of the PM noise of oscillators, amplifiers and other components. For frequencies of 5 MHz to 40 GHz, Sφ(ƒ)of oscillators and components can be determined for Fourier frequency offsets from the carrier of 0.1 Hz to a maximum of 10 MHz or 10% of the carrier. The PM noise is measured for only a few user-specified frequency offsets (typically 3 points per decade). All measurements of PM noise are made relative to 1 rad2/Hz. Typical noise floors of the measurements are shown in the table below


      Typical PM measurement noise floor for different carrier frequencies

Carrier Frequency

5 MHz

100 MHz

10 GHz

Sφ(1 Hz), [dBrad2/Hz]

-150

-145

-140

Sφ(Thermal), [dBrad2/Hz]

-187

-187

-187


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.

NIST also provides calibration services of double sideband AM noise [Sα(ƒ)] of oscillators and other components. For frequencies from 1 MHz to 40 GHz, Sα(ƒ) of oscillators and components can be determined for Fourier frequency offsets from the carrier of 0.1 Hz to a maximum of 10 MHz or 10% of the carrier. The AM noise is measured for only a few user-specified frequency offsets (typically 3 points per decade). All measurements of AM noise are made relative to a normalized average amplitude of unity, or 1/Hz.

      Typical AM measurement noise floor for different carrier frequencies

Carrier Frequency

5 MHz

100 MHz

10 GHz

Sα(1 Hz), [dB/Hz]

-137

-135

-130

Sα(Thermal), [dB/Hz]

-177

-177

-177


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.


  NIST can also provide calibration services for frequency and time domains at frequencies other than those cited in the above tests up to 110 GHz or higher. The uncertainty and cost are dependent upon the specific user requirements. Given two or more oscillators, synthesizers, frequency multiplier/dividers, or amplifiers, relative PM noise can be measured with low uncertainty and the frequency for the measurement is not as restrictive as above. Also, the 1 pulse-per-second output of an atomic frequency standard can be used for time-domain measurements of time and time stability, frequency and frequency stability. Please call to discuss your requirements.

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References—PM and AM Noise Measurements

Secondary Standard for PM and AM Noise at 5, 10, and 100 MHz, F. L. Walls, IEEE Trans. I&M 42, 126 (Apr. 1993).

Calibration uncertainty for the NIST PM/AM noise standards, A. Hati, C.W. Nelson, N. Ashby, and D.A. Howe, NIST Spec. Publ. 250-90, (July 2102).

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).

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Program questions: Calibrations
Phone: 301-975-5454, Fax: 301-975-2950
NIST, 100 Bureau Drive, Stop 8363, Gaithersburg, MD 20899-8363