Digital double boxcar integrator for pulsed NMR experiments

A simple double boxcar integrator used for averaging free induction decay (FID) signals in pulsed NMR experiments is described. The gating time circuit, the gated integrator, A/D convertor and the totaliser ¿ all these circuits have been designed and constructed with solid-state devices. The boxcar integrator is operated in the single-point mode and is capable of measuring both positive and negative signals of 2.5 V. The linearity of the boxcar is better than 0.1% in the totaliser mode.