FOURIER TRANSFORM NUCLEAR MAGNETIC RESONANCE SPECTROMETER EMPLOYING MEANS FOR GENERATING RANDOM PULSE INTERVALS TO AVOID ANOMALIES DUE TO NET TRANSVERSE MAGNETIZATION

摘要

Means for eliminating phase and intensity anomalies in high resolution nuclear magnetic resonance spectra particularly useful in impulse Fourier spectrometers wherein free induction decay signals are obtained from a sample under analysis, the demodulated free precession signals being averaged in a time-averaging computer and then Fourier-transformed and displayed as a resonance frequency spectrum. Phase and intensity anomalies are avoidable by not permitting establishment of a finite net transverse component of magnetization in the steady state regime by introducing a delay into each recycle time. Alternatively, net transverse magnetization may be permitted to occur for a set of pulses but the phase and intensity anomalies may be avoided by changing the pulse rate for each set and by time-averaging the responses of the sets of pulses, each set of pulses being a predetermined number of pulses at a fixed pulse interval for each set, the pulse intervals for each set being different from the pulse interval of said first set by a random period.