f = fwhm (y) ¶f = fwhm (x, y) ¶f = fwhm (…, "zero") ¶f = fwhm (…, "min") ¶f = fwhm (…, "alevel", level) ¶f = fwhm (…, "rlevel", level) ¶Compute peak full-width at half maximum (FWHM) or at another level of peak maximum for vector or matrix data y, optionally sampled as y(x). If y is a matrix, return FWHM for each column as a row vector.
The default option "zero" computes fwhm at half maximum, i.e. 0.5*max(y). The option "min" computes fwhm at the middle curve, i.e. 0.5*(min(y)+max(y)).
The option "rlevel" computes full-width at the given relative level of peak
profile, i.e. at rlevel*max(y) or rlevel*(min(y)+max(y)),
respectively. For example, fwhm (…, "rlevel", 0.1) computes
full width at 10 % of peak maximum with respect to zero or minimum; FWHM is
equivalent to fwhm(…, "rlevel", 0.5).
The option "alevel" computes full-width at the given absolute level of y.
Return 0 if FWHM does not exist (e.g. monotonous function or the function does not cut horizontal line at rlevel*max(y) or rlevel*(max(y)+min(y)) or alevel, respectively).
Package: signal