statistical jargon (UNCLASSIFIED)

[Mullins, Bill AMRDEC]

Classification: UNCLASSIFIED
Caveats: NONE

> Another coinage seems to be mishandled completely.
>
> Spectral, adj.
> > spectral analysis n. Chemical analysis of substances by means of
their
> > spectra; analysis of light or another oscillating system into a
spectrum.
> > 1862 /Amer. Jrnl. Sci./ *84* 404 There are few branches of science
> > which promise more magnificent results than the spectral analysis.
> > 1888 /London, Edinb. & Dublin Philos. Mag./ 5th Ser. *25* 343
> > (/heading/) Mathematical spectral analysis of magnesium and carbon.
> > 1930 /Proc. IRE/ *18* 1199 Expression (9) lends itself to spectral
> > analysis into its component frequencies by the following process.
> > 1978 /Nature/ 16 Mar. 232/2 As a further step, we carried out a
> > spectral analysis according to the techniques of Blackman and Tukey
on
> > the time series for each of our latitude bands.
>
> Note that the last quote mentions Tukey. In fact, it does not refer to
> the same kind of spectral analysis that is identified in the
definition.
> In this case, it is a purely statistical technique (hence Tukey's
name).
> Check Wiki disambiguation of "spectral analysis" for details.
>

I think that the problem with this entry is that it gives too much
weight to chemical spectral analysis as representing "spectral analysis"
as a whole.

Pretty much any quantity which can be represented in a frequency domain
can have a spectrum, and that spectrum may be analyzed.  Optical or
infrared spectra are usually what is being analyzed in chemical spectral
analysis (above); much astronomy is done this way.  Audio spectra may be
analyzed as well.  The designer of a graphic equalizer, or the crossover
network in a loudspeaker, will have to accomplish spectral analysis of a
sort.  Images may be represented in a two-dimensional frequency domain
(much image processing is done in the frequency domain), and spectral
analysis is done there as well.  (A poorly focused picture will have its
high frequency content eliminated.)  Camera lenses are described by
their Modulation Transfer Function (MTF), which may be measured
outright, or may be calculated by spectral analysis techniques.
Earthquakes, nuclear physics, radio communications, x-ray
crystallography, and many other fields all have quantities that may be
described in terms of their spectra, and spectral analysis would be the
sets of tools used to describe them.

So to my way of thinking, the definition for "spectral analysis" should
be broad and refer to the mathematical processes used to accomplish it,
and then the various fields in which it is used my be brought into play
as examples, or by citations.


Classification: UNCLASSIFIED
Caveats: NONE

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