A MICROCOMPUTER (IBM PC) BASED PULSED NMR SPECTROMETER

This paper describes the design and construction of a personal compute r (PC) based pulsed NMR spectrometer to measure spin-lattice relaxatio n times in solids. The spectrometer works at 10 MHz and produces r.f. pulses of amplitude 200 V-p-p. The pulse programmer provides various p ulse sequences such as 180 degrees-tau-90 degrees and 90 degrees-tau-1 80 degrees and inter pulse intervals (tau) can be computer programmed. The rise and fall times of r.f. pulses are less than 0.4 mu s. The re jection ratio of the transmitter is better than 3 x 10(7). The overall gain of the receiver system is 120 dB with a band width of 2 MHz. The recovery time of the receiver is 7 mu s. The PC controls the spectrom eter and data acquisition system. A detailed description of the spectr ometer is presented.