The transients produced by the pantograph electric arc and captured by a GSM-R antenna mounted on roof top are characterized in the time domain and in the joint time-frequency domain, in order to quantify the noise produced on the GSM-R channel. The recoded signals are characterized also to evaluate the behavior of the GSM-R protocol to burst noise. The measurements were performed on a 25 kV 50 Hz French line.

Below the frequency of 10 MHz, the calibration fails of electric power sensors made by means of microcalorimeters, mainly because of a reduced sensitivity of the measurement system. This produces a metrological gap in the power standard between the low frequency and radio frequency range. However, as TEM transmission line admits pseudo potential functions, power sensor calibration can be done on coaxial line also in term of RF voltage from DC up to 100 MHz at least. The paper describes how INRIM implements this calibration technique together with the obtained accuracy.

A new PD (partial discharge) measuring system calibrator is described. The device, battery operated, may be used either grounded or in a floating position, and generates securely mains-synchronized impulses by capacitive coupling. It allows the determination of the scale factor k and resolution time T r in PD measuring systems, and it fulfils the requirements of International Standard IEC 60270. PD measuring instruments have mains-synchronized sweeps. Hence, in order to have stationary calibration impulses in the PD measuring instrument, the calibrator must generate mains-synchronized impulses. Usually, PD calibrators synchronize to mains frequency by a photodiode. In case of insufficient pick-up of power frequency light, these calibrators automatically select an internal quartz oscillator. When the internal oscillator is on, there is usually a slight difference between the oscillator frequency (fixed) and the mains frequency (variable), and consequently the impulses generated by the internal oscillator are not stationary in the PD measuring instrument (detector screen). This new calibrator avoids that problem because it generates securely mains-synchronized impulses by capacitive coupling, making unnecessary an internal quartz oscillator.

The Inmetro Thermometry Laboratory uses fixed-points cells defined in the International Temperature Scale of 1990 (ITS-90) to calibrate thermocouples andstandard platinum resistance thermometers. In order to meetthis, the laboratory counts on reference fixed-point cellsfrom theArgon triple point (-189,3442°C) to the Copperfixed-point (1084,62°C). In a quest to improve its best measurement capability and to disseminate this, thelaboratory has been investing in the manufacture of its own primary standards. This process was started with water triple point cells, mercury triple point cells and pure noble metalthermocouples which have results validated through comparisons and are part of the laboratory standards regularly used in calibrations. The following step came to be an open metal cell. Zinc was chosen for being relatively inexpensive. The methodology and the corresponding results achieved were published in 2006 and 2008. Going on with this task, the laboratory constructed a Tin cell in 2010.All Inmetro cells are open, and they were compared to the three commercially available cells the laboratory previously had. The materials, methodology, uncertainty evaluation (impurity effect estimates) and results are discussed in the present paper.

It is well known, that the proper ratio between frequencies of testing signal and sampling signal is required, during a dynamic testing of waveform recorders or analog-to-digital converters. A lot of testing methods suggest applying a coherent sampling, which assures a uniform distribution of samples between 0 and 2π. The paper presents results obtained with Matlab numerical simulations showing influence of the sampling strategy on establishing performances of analog-to-digital converters. It was shown, that the results of tested conversions are different if a non-coherent sampling is applied. A proposal of sampling is presented in case of using a sinewave as an exciting, input signal.