AN AUTOMATICALLY STABILIZED BRIDGE NUCLEAR MAGNETIC RESONANCE SPECTROMETER

A twin-T bridge nuclear magnetic resonance spectrometer is described in which the bridge has two outputs. The nuclear magnetic resonance signal from one output is accompanied by an in-phase r.f. leakage voltage, so that the dispersion mode of the signal is obtained on detection, whereas the other output contains an out-of-phase leakage voltage, so that the absorption mode is obtained. A stabilizing system ensures that the leakage signals remain at a fixed level of attenuation with respect to the input to the bridge. The absorption and dispersion signals may be simultaneously recorded. A bridged-T circuit employing a p-i-n diode can be stabilized in the same way.