Teledyne LeCroy WaveExpert 100H Operators Manual - Manual (Page 119)

Wave Expert
WE-OM-E Rev A
117
Histogram Parameters
fwhm Full Width at Half Maximum
Definition: Determines the width of the largest area peak, measured between bins on
either side of the highest bin in the peak that have a population of half the
highest's population. If several peaks have an area equal to the maximum
population, the leftmost peak is used in the computation.
Description: First, the highest population peak is identified and the height of its highest bin
(population) determined (for a discussion on how peaks are determined see
the pks parameter Description:). Next, the populations of bins to the right and
left are found, until a bin on each side is found to have a population of less
than 50% of that of the highest bin's. A line is calculated on each side, from the
center point of the first bin below the 50% population to that of the adjacent
bin, towards the highest bin. The intersection points of these lines with the
50% height value is then determined. The length of a line connecting the
intersection points is the value for fwhm.
Example: