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ResistiveProbehead

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Magnetically ordered materials, in particular those presenting ferro- and ferri-magnetic order, may display a large amplification of the applied radio frequency (r.f.), called r.f. enhancement. In these special cases a resonant circuit for NMR transission and detection may not be strictly needed, since the transmitter r.f. power may be enough to produce an observable NMR signal. In this case the NMR coil can be simply put in series with a 50 Ohm resistor, to match the cable and transmitter's impedance.

This greatly simplifies data acquisition because such a probehead allows the recording of the NMR signal over a large frequency interval without requiring tuning of the circuit at each new frequency, like in the previous case of the LC probehead.

< The probehead | Index | The receiver block diagram >