Wideband Feedback Coherence Control for Superregenerative NQR Spectrometers

Abstract

A description is given of a wideband feedback coherence control system for superregenerative NQR spectrometers. By making use of a servo motor to adjust the oscillator grid bias, increases in rf searching band are possible. As an example, a bandwidth of 30 Mc around a center frequency of 70 Mc has been obtained. The sensitivity of the circuit to nuclear quadrupole resonance signals is high. The spectrometer will operate unattended.