Tuned limiter for receiver amplifier in a fast-recovery pulsed NMR spectrometer

A simple tuned limiter is described which limits the rf voltage amplitude at the input of the receiver amplifier of a pulsed NMR spectrometer. This device prevents overload of the receiver amplifier during the high-power rf pulse and thereby allows fast recovery of the spectrometer following the pulse. When used with Avantek unit amplifiers at 24 MHz, a recovery time of 2.5 mus is achieved.