DATA-ACQUISITION AND PULSE GENERATION SYSTEM FOR NUCLEAR-MAGNETIC-RESONANCE SPECTROMETERS ON A SINGLE PC-ISA COMPATIBLE BOARD

A data acquisition and pulse generation system for NMR spectrometers i s described. It has been implemented on a single board for MS-DOS pers onal computers with an ISA standard bus interface and uses a simple ar chitecture optimizing the integration of the hardware and software res ources. The system, owing to its versatility and low cost, is particul arly suitable to upgrade old pulsed NMR instruments with outdated data and control systems, for applications where expensive new cryomagneti c instruments would be inappropriate, such as in industrial control or as educational tools. The board provides two simultaneous data acquis ition channels allowing 250000 12-bit conversions per second per chann el. including real-time signal averaging, and is able to produce essen tially any pulse sequence on several output lines. The duration of eac h pulse can range from 0.1 mu s to 180 s with a minimum pulse separati on of 5 mu s and with a resolution of 0.1 mu s. All classic NMR pulse sequences are allowed in addition to those required for self-diffusion coefficient measurements using pulsed magnetic field gradients. All f unctions of the system are managed by machine-language routines callab le from within a VisualBASIC program. The cost of the hardware of this device is under US$500.