Non-linearity in the ISDB-T transmission chain causes intermodulation products that widens the spectrum emission and should be taken into account to assign frequency channels. The characterization of the transmission spectrum mask is one of the most important measurements in order to achieve the best use of the electromagnetic spectrum. The use of critical mask defined in [1] allows allocations of co-site adjacent channels for anefficient use of the electromagnetic spectrum that is a finite and limited resource. In this paper different test procedure using spectrumanalyzer and dedicated...
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.
The dc voltage fluctuation (sometimes referred to as ripple) is considered for the pantograph voltage on dc railways. Some indexes and processing techniques are considered to evaluate steady state and transient phenomena: Ripple Index based on time and frequency domain expressions, DFT and wavelet analysis.
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.
The complex Ukrainian national electrical standards of national metrological institute "Ukrmetrteststandard", their key and supplementary comparisons and calibration and measurement capabilities "Ukrmetrteststandard" in electrical and magnetism field are considered.
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...
Two methods for the estimation of harmonic parameters of periodic arbitrary signals were compared: a method based on least squares and a Bayesian method using approximations based on the normal distribution and the posterior mode. The methods are reviewed and compareison results are presented and analyzed in this paper.
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...
The traceability chain to derive the capacitance unit from the quantum Hall resistance coaxial bridges. These bridges employ an inductive voltage divider to provide the voltage ratio needed. One such divider has recently been constructed calibrated at Inmetro. The design techniques responsible for the small ratio errors of the device are detailed.
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...