Full Width at Half-Maximum

Calculating full width at half maximum (FWHM, aka line width). This function returns the ppm difference where peak line crosses half of the peak height. It requires one signal across all spectra within ppm ranges specified in shift.

lw(X, ppm, sh = c(-0.1, 0.1), sf)

Arguments

X	num matrix, NMR data with rows representing spectra.
ppm	num array describing chemical shift positions, its length equals to nrow(X).
sh	num array(2), chemical shift range of a singlet for which fwhm is calculated
sf	num, operating frequency of the spectrometer (meta$SFO1)

Value

Array of line widths in ppm. To convert from ppm to Hertz (Hz), multiply values with the spectrometer frequency (column a_SF01 in meta data frame).

See also

Other estimation: get_idx(), noise(), shift_pickr()

Author

Torben Kimhofer torben.kimhofer@murdoch.edu.au

Examples

read_in(path = system.file('extdata',package='concentr8r'),
        exp_type = list(exp=c("PROF_URINE_NOESY")),
        n_spec='multiple')
lnw <- lw(X, ppm, sh = c(-0.1, 0.1), meta$a_SF01)
bad <- which(lnw>1)
if (length(bad)!=0){cat("The spectra", bad, "have line widths over 1")
} else {cat("All Spectra have line widths under 1")}
#> All Spectra have line widths under 1