Because the DAFS and XAFS signals have limited photoelectron wavenumber
``bandwidths'', their information content is limited. The number of
independent XAFS points is given by 
, where
is the filtering window width in R-space and 
is the
window width in K-space [24]. For typical values, 
Å and 
, the number of independent points
is approximately 10. This is the maximum number of parameters that can
be determined from single shell XAFS data. Note, however, that if there
are m inequivalent sites, a set of DAFS measurements for m or more
inequivalent reflections can provide up to m times as much information as
XAFS. If there are also p components in the sample, and each component
has m inequivalent sites, then a total of (pmN) parameters can be
determined per shell.