Phase noise inter-laboratory comparison preliminary results

Some phase noise benches used and developed by different research and commercial laboratories have to be tested. The problem is not to compare the performances of several oscillators, but to compare and to make an evaluation of the uncertainties, and of course, to compare the resolution and the reproducibility of the measurements, which are of interest for manufacturers. This comparison allows us to determine the ability to get various systems traceable together in order to increase the trust that one can have in phase noise measurements. Standards to be characterized during this comparison are 5 MHz, 100 MHz and microwave commercial oscillators. Obtained spectra can be affected by the Environmental conditions: temperature, hygrometry, electromagnetic radiations, voltage supplies of oscillators under test and measurement instrumentation, but they also depend on starting conditions of the oscillators and due to their intrinsic nature, and to the time they have been stocked after being switched-off and to the benches themselves. The problem consists in evaluating the possible different contributions. These goals are ambitious, so it is preferable to investigate in priority the inter-laboratory reproducibility in using comparable benches or benches that use equivalent methods, but also measurements resulting from various methods, while we stay in the context of measurements performed in a laboratory. It began in October 2005 and will be finished in april 2006. Preliminary results are now available.