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EMI Measurements, Control Requirements, and Test Methods
Published in David A. Weston, Electromagnetic Compatibility, 2017
The best type of signal source in a radiated or conducted susceptibility test is the analog sweep generator or a frequency synthesizer that can sweep continuously over the frequency range of interest. The disadvantage of the analog type of generator is that typically the sweep must be made manually. A frequency synthesizer-based generator, on the other hand, may usually be programmed via pushbuttons on the front panel or via a computer, using a computer interface such as the GPIB bus. The more modern frequency synthesizer sweep generator is similar to an analog generator and sweeps continuously, whereas the older or simpler types sweep by stepping the frequency. The susceptibility of an EUT often occurs at a single frequency or a limited number of frequencies. This selectivity is commonly a result of increased current flow in circuits or cables at resonance. Depending on the Q of the resonant circuit, the susceptibility may be seen only at a single frequency, with a sharply decreased response either side of that frequency. Use of a generator that must be stepped in frequency, despite a small step size, increases the possibility that a resonant frequency at which susceptibility occurs may be missed. A potential disadvantage of the frequency synthesizer generator is the typically high level of harmonics generated compared to an analog generator. Power amplifiers are required to generate the specified level of E field in a radiated susceptibility test and the specified voltage at the input of the EUT in a conducted susceptibility test. Some examples of the frequency range and typical output powers of amplifiers are provided in Table 9.2. An amplifier is available from Dressier that is rated at 75 W from 9 kHz to 250 MHz, and this is capable, with the majority of antennas and injection probes, of generating the EN 50081-2 C/M RF test level and the RF electromagnetic field of EN 50081-2 and EN 50082-1 up to 250 MHz.
Signal Simulators and Emulators
Published in Felix Alberto Farret, Marcelo Godoy Simões, Danilo Iglesias Brandão, Electronic Instrumentation for Distributed Generation and Power Processes, 2017
Felix Alberto Farret, Marcelo Godoy Simões, Danilo Iglesias Brandão
The sweep generator generates signals with variable frequency in a linear fashion, repeated automatically and within a given range of values. This instrument is used to analyze the frequency response of circuits. A typical scheme of this instrument is shown in Figure 5.12.
Peculiarities of conductivity of PbSnTe(In) in the persistent photoconductivity regime.
Published in J Kono, J Léotin, Narrow Gap Semiconductors, 2006
A E Kozhanov, S N Chesnokov, L I Ryabova, D R Khokhlov
For applying high frequency electric field, we have used a sweep-generator that allowed us to sweep the frequency in the 50 - 650 MHz range. The DC conductivity was measured using the 2-probe technique.
MEPhIST-0 Tokamak for Education and Research
Published in Fusion Science and Technology, 2023
S. Krat, A. Prishvitsyn, A. Alieva, N. Efimov, E. Vinitskiy, D. Ulasevich, A. Izarova, F. Podolyako, A. Belov, A. Meshcheryakov, J. Ongena, N. Kharchev, A. Chernenko, R. Khayrutdinov, V. Lukash, D. Sinelnikov, D. Bulgadaryan, I. Sorokin, K. Gubskiy, A. Kaziev, D. Kolodko, V. Tumarkin, A. Isakova, A. Grunin, L. Begrambekov, R. Voskoboinikov, A. Melnikov
Instead of a centralized analog-to-digital conversion system, the recording of the current flowing in the probe circuit and the voltage on the probes is carried out using a digital oscilloscope with isolated channels. To sync the moment of measurement with the discharge in the tokamak, a centralized pulse delay generator is used. If there is no need to localize the measurements of plasma parameters in time, the voltage sweep generator is operated in a continuous mode, and the pulse from the syncing generator is used to trigger the oscilloscope. As a sweep generator, an arbitrary waveform generator AKIP-3413/2 is used, set to output a sawtooth signal. This signal is symmetrically bipolar, with a magnitude range of 1 to 5 V peak to peak. Since this signal is too small and has no offset, the required voltage on the probes is generated after its boosting by a specially designed amplifier unit AU-10. Its output voltage sweep is in the range +5 to –275 V, and the bandwidth without signal distortion is 40 to 15 kHz. The amplifier supports both continuous and pulsed (burst) operation modes, with a maximum output current of 800 mA per channel (10 channels in total).