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Noise measurement of a preamplifier with high input impedance using an NMR console |
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| Affiliation: | 1. Faculty of Electrical Engineering, University of Ljubljana, Tr?a?ka 25, 1001 Ljubljana, Slovenia;2. Metrel d.d., Ljubljanska cesta 77, SI-1354 Horjul, Slovenia;1. Civil Eng. Dept., University of Malaya, 50603 Kuala Lumpur, Malaysia;2. Institute of Environmental and Water Resources Management, Universiti Teknologi Malaysia, Skudai, Johor, Malaysia;1. Department of Electrical Engineering, University of Córdoba, Córdoba 14071, Spain;2. Department of Physics, University of Córdoba, Córdoba 14071, Spain;1. ENEA Brasimone, Camugnano, BO, Italy;2. Dipartimento di Energia, Ingegneria dell’Informazione e Modelli Matematici, Università di Palermo, Viale delle Scienze, Palermo, Italy;3. ENEA Bologna, Via Martiri di Monte Sole 4, Bologna, Italy |
| Abstract: | This article describes the noise measurement of a preamplifier with high input impedance designed for experiments with receive coils in nuclear magnetic resonance (NMR). The noise of the preamplifier was determined in two ways. A circuital analysis of the preamplifier provided an equation for the preamplifier noise calculation and the noise voltage was measured with an NMR console and in accordance with known theory the measured analogue noise signal was modified to a discrete noise signal. An objective function with noise parameters of the preamplifier as variables was created. The noise parameters of the preamplifier were calculated with an optimization procedure and the results of the calculation and of the measurement compared. Qualitative and quantitative agreement was good. It was proved that the noise parameters of a preamplifier for NMR experiments can be measured with an NMR console and derived theory. |
| Keywords: | Low-field NMR Noise measurement Receive coil High input impedance Preamplifier Optimization procedure |
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