FWHM

This abbreviation refers to the mathematical function of full width at half maximum. FWHM is defined as the difference between the two extreme values of an independent variable at which the dependent variable is equal to half of its maximum value. In other words, it is the width of a spectrum curve measured between those points on the y-axis that are half the maximum amplitude. FWHM is a common form of measurement for pulse waveforms, and the spectral width of sources used for optical communications. This is also used in signal processing to define bandwidth as the “width of frequency range where less than half the signal’s power is attenuated.”