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Search Publications by: Michael A. Lombardi (Assoc)

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Displaying 126 - 150 of 287

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

Time and Frequency Transfer Activities at NIST

December 1, 2008
Author(s)
Victor S. Zhang, Michael A. Lombardi
The National Institute of Standards and Technology (NIST) maintains one of the world s most accurate and stable time scales, and also developed and maintains the primary frequency standard for the United States. Various techniques are used to compare the

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

The SIM Network: Improved Time Coordination for North, Central, and South America

April 23, 2008
Author(s)
Jose M. Lopez, Michael A. Lombardi, Andrew Novick, Jean-Simon Boulanger, R. de Carvalho, R. Solis, Francisco Jimenez
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

Selecting a Primary Frequency Standard for a Calibration Laboratory

April 1, 2008
Author(s)
Michael A. Lombardi
Calibration laboratories can choose from a variety of frequency standards, including quartz oscillators, atomic oscillators, and oscillators disciplined to agree with reference signals from the Global Positioning System (GPS) satellites or other sources

The Accuracy and Stability of Quartz Watches

February 1, 2008
Author(s)
Michael A. Lombardi
A short review article about quartz wristwatches that presents measurements of their accuracy and stability. Measurements of both the stepping motors and crystal oscillators inside four quartz watches are made over a 30-day interval, and the results are

NIST Primary Frequency Standards and the Realization of the SI Second

December 1, 2007
Author(s)
Michael A. Lombardi, Thomas P. Heavner, Steven R. Jefferts
As the base unit of time interval, the second holds a place of preeminence in the world of metrology. Time interval, and its reciprocal, frequency, can be measured with more resolution and less uncertainty than any other physical quantities. The precise