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Displaying 101 - 125 of 130

High Spectral purity oscillator at 40 GHz: Design using air-dielectric Cavity

June 2, 2010
Author(s)
Archita Hati, Craig W. Nelson, Billy F. Riddle, David A. Howe
We describe the design of a low-PM noise 40 GHz oscillator that uses a conventional air-dielectric cavity resonator as a frequency discriminator to clean up the PM noise of a commercial 10 GHz dielectric resonator oscillator (DRO) multiplied by four. The

Low-Frequency Characterization of MEMS-Based Portable Atomic Magnetometer

June 2, 2010
Author(s)
Rahul R. Mhaskar, Svenja A. Knappe, John E. Kitching
Atomic magnetometers based on absorption or polarization rotation of light in an alkali vapor have recently demonstrated sensitivities rivaling those of superconducting quantum interference devices (SQUIDs). Miniaturization of such devices containing vapor

Medium-Term Frequency Stability of Hydrogen Masers as Measured by a Cesium Fountain

June 2, 2010
Author(s)
Thomas E. Parker, Steven R. Jefferts, Thomas P. Heavner
Abstract Hydrogen masers are used extensively in time scale ensembles, but the frequency drift must be accurately known. NIST-F1, the cesium fountain primary frequency standard at the National Institute of Standards and Technology, now operates nearly

Phase noise suppression in frequency comb generators

June 2, 2010
Author(s)
Craig W. Nelson, Archita Hati, J F. Nava-garcia, David A. Howe
We propose an idea to suppress the flicker (1/f) noise in radio frequency (RF) multiplier based frequency comb generators. Comb generators are often used for frequency multiplication in frequency synthesis. In general, comb generators apply high power to a

A common-view disciplined oscillator

May 24, 2010
Author(s)
Michael A. Lombardi, Aaron P. Dahlen
This paper describes a common-view disciplined oscillator (CVDO) that locks to a reference time scale through the use of common-view Global Positioning System (GPS) satellite measurements. A Proportional-Integral-Derivative (PID) controller obtains near

How Accurate is a Radio Controlled Clock?

March 1, 2010
Author(s)
Michael A. Lombardi
This paper discusses the factors that determine the accuracy of radio controlled clocks. The topics covered including the accuracy of the time signal station, path delay, synchronization errors, and the time error that accumulates between synchronizations.

NIST Time and Frequency Bulletin

January 5, 2010
Author(s)
Eyvon Petty
The Time and Frequency Bulletin provides information on performance of time scales and a variety of broadcasts (and related information) to users of the NIST services)

Distributing UTC(NIST) to Industrial Time and Frequency Users

November 18, 2009
Author(s)
Michael A. Lombardi, Victor S. Zhang
The National Institute of Standards and Technology (NIST) maintains one of the world s most accurate and stable time scales, UTC(NIST), as well as the NIST-F1 cesium fountain, the primary frequency standard for the United States. These standards are

Limits on GPS Carrier Phase Time Transfer

November 16, 2009
Author(s)
Marc A. Weiss
The stability of differential delays between Global Navigation Satellite receivers is critical for time and frequency transfer. We study the limit of this transfer between two specific receivers from the study of data taken from these receivers while they

Novel, All-Digital Phase Measurement System for Time Scales

November 16, 2009
Author(s)
Stefania Romisch, Thomas E. Parker, Steven R. Jefferts
A novel, all-digital phase measurement system, to be utilized as part of the NIST Time Scale at NIST in Boulder, CO is presented. The system is used to compare output signals from several commercial atomic frequency standards: the phase differences between

Phase-lock Loops in Vibration Environments

November 16, 2009
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
A popular scheme for achieving low phase noise across a large range of offset frequencies is to employ an oscillator at an output frequency with low far-from-carrier noise that is phase-locked to a reference that has low close-to-carrier noise. We

Two-Way Satellite Time and Frequency Transfer Using 1 MChip/S codes

November 16, 2009
Author(s)
Victor S. Zhang, Thomas E. Parker, Demetrios Matsakis, Joseph Achkar, Daniele Rovera, Dirk Piester, Andreas Bauch, Luca Lorini
The Ku-band transatlantic and Europe to Europe two-way satellite time and frequency transfer (TWSTFT) operations used the 2.5 MChip/s pseudo-random codes with 3.5 MHz bandwidth until the end of July, 2009. The cost of TWSTFT operation is associated with

Optical frequency stabilization of a 10 GHz Ti:sapphire frequency comb by saturated absorption spectroscopy in 87Rubidium

November 4, 2009
Author(s)
Dirk Heinecke, Albrecht Bartels, Tara M. Fortier, Danielle Braje, Leo Hollberg, Scott A. Diddams
The high power per mode of a recently-developed 10 GHz femtosecond Ti:sapphire frequency comb permits nonlinear Doppler-free saturation spectroscopy in 87Rubidium with a single mode of the comb. We use this access to the natural linewidth of the Rubidium

WWVB Radio Controlled Clocks: Recommended Practices for Manufacturers and Consumers (2009 edition)

September 8, 2009
Author(s)
Michael A. Lombardi, Andrew N. Novick, John P. Lowe, Matthew J. Deutch, Glenn K. Nelson, Douglas D. Sutton, William C. Yates, D. W. Hanson
Radio controlled clocks represent a true revolution in timekeeping. Clocks that synchronize to NIST radio station WWVB now number in the millions in the United States, and new sales records are being established every year. As a result, many of us are now

Establishment of the SIM Time Scale

August 1, 2009
Author(s)
J. Mauricio Lopez-Romero, N. Munoz, Michael A. Lombardi
The SIM time and frequency metrology working group has developed a comparison network for the Americas, with the goals of improving metrology in the SIM region and to allow as many countries as possible to participate in the network. As of May 2008, ten

The SIM Time Network and its Contributions to Metrology in the Americas

April 1, 2009
Author(s)
Michael A. Lombardi
The SIM Time Network (SIMTN) has been one of the great success stories of the Sistema Interamericano de Metrologia (SIM), a regional metrology organization (RMO) that includes the 34 member nations of the Organization of American States (OAS). The SIMTN

Stopwatch and Timer Calibrations (2009 edition)

January 28, 2009
Author(s)
Jeff C. Gust, Robert M. Graham, Michael A. Lombardi
Stopwatch and timer calibrations are perhaps the most common calibrations performed in the field of time and frequency metrology. Hundreds of United States laboratories calibrate many thousands of timing devices annually to meet legal and organizational

The SIM Time and Frequency Network

December 1, 2008
Author(s)
Michael A. Lombardi, Andrew N. Novick, Jose M. Lopez, Francisco Jimenez, Jean-Simon Boulanger, Raymond Pelletier, Ricardo de Carvalho, Raul Solis, Carlos Donado, Harold Sanchez, Carlos A. Quevedo, Gregory Pascoe, Daniel Perez
The Sistema Interamericano de Metrologia (SIM) consists of national metrology institutes (NMIs) located in the 34 member nations of the Organization of American States (OAS), which extends throughout North, Central, and South America, and the Caribbean

Establishment of the SIM Time Scale

October 22, 2008
Author(s)
Michael A. Lombardi, Nelida Diaz-Munoz, J. Mauricio Lopez-Romero
The SIM time and frequency metrology working group has developed a comparison network for the Americas, with the goals of improving metrology in the SIM region by allowing as many countries as possible to participate in the network. As of May 2008, 10

Handbook of Frequency Stability Analysis

July 1, 2008
Author(s)
William Riley, David A. Howe
This handbook, which can be used as both a tutorial and a reference, describes practical techniques for frequency stability analysis. It covers the definitions of frequency stability, measuring systems and data formats, pre-processing steps, analysis tools

The First Measurements with Octave-Spanning Femtosecond Laser Frequency Combs

March 13, 2004
Author(s)
Scott A. Diddams, David J. Jones
Here we describe in a historical manner the first optical frequency measurement measurements with octave-spanning frequency combs and the first measurement and stabilization of the carrier-envelope offset frequency for a train of femtosecond laser pulses.

Atomic Time

January 1, 2002
Author(s)
Thomas E. Parker, Marc A. Weiss
Displaying 101 - 125 of 130