High Stability ``Boxcar'' Integrator for Fast NMR Transients in Solids

Abstract

An improved double channel electronic sampling integrator with digital output is described which is particularly suitable for enhancing signal‐to‐noise in pulsed NMR studies in solids where narrow sampling gate widths and long data memory are essential. The sampling gate widths are 1 μsec or less. The difference signal between the channel inputs is converted to digital form and stored in a standard counter which may be modified to add successive counts, thereby computing the mean numerically. Since there is no analog integration the system has a pulse response time of 1 μsec. The system is free of ion or grid current drift problems common to previous designs. Thermal drift is small. Details of the circuits and graphs of integrating performance are presented.