The overall width in hertz needed to observe a particular NMR spectrum. This width is generally set using the Nyquist limit; namely, that the temporal sampling rate must be equal to twice the maximum spread in frequencies.

The part of the NMR system that actually produce the NMR phenomenon and acquire the signals, including the magnet, the probe, the RF circuitry, the gradient coils, etc. The spectrometer is controlled via the interface.

For the wide uses of NMR spectroscopy (from mineralogy to medicine) there is a variety of different spectroscopic imaging techniques available.
A short listing of the most frequent variations:

Edward Purcell and Felix Bloch discovered the basic of spectroscopy in 1946 (see MRI History). Nuclear magnetic resonance spectroscopy (NMR Spectroscopy or MRS) is an analytical tool, based on nuclei that have a spin (nuclei with an odd number of neutrons and/or protons) like 1H, 13C, 17O, 19F, 31P etc.
Through nuclear magnetic principles as precession, chemical shift, spin spin coupling etc., the analysis of the content, purity, and molecular structure of a sample is possible. The spectrum produced by this process contains a number of peaks; the highs and the positions of these peaks allow the exact analysis. Unknown compounds can be matched against spectral libraries. Even very complex organic compounds as enzymes and proteins can be determined. For the wide uses of NMR spectroscopy (from mineralogy to medicine) there is a variety of different techniques available.
See Spectroscopic Imaging Techniques.

An array of the frequency components of the MR signal according to frequency. Nuclei with different resonant frequencies will show up as values at different corresponding frequencies in the spectrum. When resonances are relatively isolated they appear as peaks or lines in the spectrum.
A spectrum is also a graphic representation of the range over which a quantity extends.