Abstract
An improved analysis of continuous wave (cw) NMR detection by Q‐meters is presented which explicitly includes parallel resistive loading of the sample coil and frequency dependent losses caused by the rf skin effect. A versatile MOSFET Q‐meter is described which operates at frequencies up to 60 MHz and rf input levels between 2 and 100 mV peak‐to‐peak. The noise figure is shown to be less than 3 dB at 8 MHz and a 7 mV peak‐to‐peak rf level. A comparison of Q‐meters with other types of cw NMR detectors is given, and their advantages for accurate line‐shape and susceptibility experiments are discussed.
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