Kyriazis G.A.,National Institute of Metrology of Brazil |
Moreno J.A.,CENAM |
18th IMEKO TC4 Symposium on Measurement of Electrical Quantities 2011, Part of Metrologia 2011 | Year: 2011
The traceability chain to derive the capacitance unit from the quantum Hall resistance comprises some coaxial bridges. These bridges employ a main two-stage inductive voltage divider to provide the voltage ratio needed. One such divider has recently been constructed and calibrated at Inmetro. The design techniques responsible for the small ratio errors of the device are detailed. Copyright © 2011 by the International Measurement Confederation (IMEKO) All rights reserved.
Shtin N.,Centro Ind Los Pinos |
Asia-Pacific Microwave Conference Proceedings, APMC | Year: 2010
In this paper we present the design and preliminary results of an experimental evaluation of C-band microwave oscillators with combined frequency stabilization based on Sapphire Whispering Gallery Resonators (WGR). Design features and phase noise performance of both the main oscillator loop and a frequency stabilization system are presented. The frequency stabilization loop has been implemented using a high sensitivity "noiseless" frequency discriminator based on a traveling wave WGR. The intrinsic phase noise of the oscillator electronics has been minimized utilizing low 1/-noise silicon and SiGe discrete components and ICs. The single-sideband phase noise of 128 dBc/Hz and 133 dBc/Hz at 1 kHz offset has been measured for free-running oscillators with Pres = 0.15 W and Pres = 0.4 W respectively. An estimate for the phase noise of the stabilized oscillators has been made involving a phase transfer function approach. © 2010 IEICE Institute of Electronics Informati.
Ortega-Cortes R.,CENAMEP AIP |
Mendez-Lango E.,CENAM |
Araolaza-Rodriguez A.,CENAMEP AIP
AIP Conference Proceedings | Year: 2013
We present the results of the design, construction, filling and test of thermometric cell, to reproduce the triple point of mercury in the Temperature Laboratory of Centro Nacional de Metrología de Panamá AIP (CENAMEP AIP). This cell will be included in the group of thermometric cells of the laboratory. With this cell CENAMEP-AIP is covering the-39°C to 660°C range. This new cell offers the opportunity to reproduce the primary temperature defined by ITS-90 of-38.8344° C, and was built with 0.68 kg of mercury ultra-pure certified by the National Institute of Standards and Technology from United States (NIST-EEUU). The reproducibility obtained with thermometric cell of mercury is approximately one thousandth of kelvin (1 mK). This value satisfies according to current laboratory equipment. © 2013 AIP Publishing LLC.
Marmet L.,National Research Council Canada |
Dube P.,National Research Council Canada |
Shtin N.,SMK Electronica S.A. de C.V. |
2013 Joint European Frequency and Time Forum and International Frequency Control Symposium, EFTF/IFC 2013 | Year: 2013
A preliminary calculation of the frequency shifts resulting from the distributed phase of a rectangular cavity is used to model frequency measurements of the fountain clock NRC-FCs1. The calculation is based on a numerical evaluation of the cavity field made with a finite element EM solver. The frequency shift is obtained by solving the Bloch-equations numerically along the path of the atoms on the free-fall trajectories through the cavity. We study the frequency shifts as a function of the launch direction, the tilt of the physics package and offsets in the position of the MOT relative to the axis defined by the state-selection cavity and the Ramsey cavity. © 2013 IEEE.
Koffman A.,U.S. National Institute of Standards and Technology |
Zhang N.F.,U.S. National Institute of Standards and Technology |
Wang Y.,U.S. National Institute of Standards and Technology |
Shields S.,U.S. National Institute of Standards and Technology |
And 12 more authors.
CPEM Digest (Conference on Precision Electromagnetic Measurements) | Year: 2012
A key comparison of capacitance has been carried out by the Inter-American Metrology System (SIM) Regional Metrology Organization (RMO). The purpose is to establish the degree of equivalence of capacitance between the national metrology institutes (NMIs) within SIM, in support of the International Committee for Weights and Measures (CIPM) Mutual Recognition Agreement (MRA). The key comparison artifact is a 10 pF commercial fused-silica standard capacitor. Seven SIM NMIs participated in the comparison. Results linking the SIM.EM-K4 to CCEM-K4 will show agreement of SIM NMIs to other RMOs. © 2012 IEEE.