MODEL RELEASED. NMR spectrometer. Researcher adding a sample to a nuclear magnetic resonance spectrometer (NMR). NMR spectroscopy utilizes the spin of certain chemical nuclei, which generate magnetic fields. When these magnetic nuclei are subjected to a uniform magnetic field their attempts to line up with the field result in a wobble or precession about the field direction. This precession frequency depends on the type of nucleus and strength of field. Nuclei are identified by measuring their precession frequencies at a known field strength.