NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Michael A. Lombardi, J. Mauricio Lopez-Romero, Nelida Diaz-Munoz
Abstract
This paper presents an analysis of the performance of some of the time scales generated in the Sistema Interamericano de Metrologia (SIM) region. We emphasize the generation of the first international time scale in near real time, the SIM Time scale (SIMT). The SIMT can be used as a reference to evaluate the performance of the time scales of the region taking advantage on the fact that values of the SIMT are disseminated through the web site of the SIM Time and Frequecy Metrology Working Group in real time.
Lombardi, M.
, , J.
and Diaz-Munoz, N.
(2010),
SIM time scales, Proc. 2010 CENAM Symposium of Metrology, Santiago de Queretaro, -1, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=906268
(Accessed October 11, 2025)