Data acquisition and pulse generation system for nuclear magnetic resonance spectrometers on a single PC-ISA compatible board

摘要

A data acquisition and pulse generation system for NMR spectrometers is described. It has been implemented on a single board for MS-DOS personal computers with an ISA standard bus interface and uses a simple architecture optimizing the integration of the hardware and software resources. The system, owing to its versatility and low cost, is particularly suitable to upgrade old pulsed NMR instruments with outdated data and control systems, for applications where expensive new cryomagnetic instruments would be inappropriate, such as in industrial control or as educational tools. The board provides two simultaneous data acquisition channels allowing 250 000 12-bit conversions per second per channel, including real-time signal averaging, and is able to produce essentially any pulse sequence on several output lines. The duration of each pulse can range from 0.1 μs to 180 s with a minimum pulse separation of 5#s and with a resolution of 0.1μs. All classic NMR pulse sequences are allowed in addition to those required for self-diffusion coefficient measurements using pulsed magnetic field gradients. All functions of the system are managed by machine-language routines callable from within a VisuaIBASIC program. The cost of the hardware of this device is under US