A BROAD-BAND NUCLEAR-MAGNETIC-RESONANCE SPECTROMETER - DIGITAL PHASE-SHIFTING AND FLEXIBLE PULSE PROGRAMMER

A simple, low-cost pulse nuclear magnetic resonance (NMR) spectrometer is described. There are two key features of the instrument: (1) all r adio frequency phase shifting is done digitally with a new-generation frequency synthesizer and (2) the pulse programmer is based on a high- speed 32-bit parallel interface card in a desktop computer. The spectr ometer is well suited for single-frequency channel experiments such as nuclear quadrupole resonance and deuterium quadrupole echo NMR experi ments. Because the rf phase shifting is done digitally, the spectromet er operates easily over a wide frequency range, here 10-300 MHz. The p ulse programmer and other software functions are written in LabView, a graphical programming language.