In Fourier Transform lon Cyclotron Resonance Mass Spectrometry, the signals of the ions cyclotron orbital motions undergo periodically destructive interference on the time scale of the measurement if the frequencies of these motions are closely-spaced. This results into a beat pattern in the measured time-domain signal.

ASMS

van Rooij, G. J., Easterling, M. L., Amster, I. J., & Heeren, R. (1999). Isotope beating effects in the analysis of polymer distributions by Fourier Transform Mass Spectrometry. In Proceedings of the 47th ASMS conference on Mass Spectrometry and Allied Topics, Dallas, Texas, June 13-17, 1999 [published on CD-ROM only] (pp. 379–380).