A Low Input Impedance MRI Preamplifier Using a Purely Capacitive Feedback Network
نویسندگان
چکیده
R. Oppelt, M. Vester Corporate Technology, Siemens AG, Erlangen, Germany, Medical Solutions, Siemens AG, Erlangen, Germany Introduction: MRI preamplifiers need to meet a number of technical requirements that are not easily to be achieved simultaneously. Major challenges are a low noise figure (e.g. <= 0.5 dB), a stable gain and a high dynamic range. In addition, the small signal input impedance, in in in i v z / = , should be very low (≤ 5 Ω) so that a sufficient decoupling of adjacent and second neighbour loops in an MRloop array is obtained. A low in z is usually realized by means of a resonant step-up LC-network at the input (s. [1]). In order to keep the
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