Signal-averaging techniques

Each of the two noise-methods mentioned uses a periodic excitation by noise to produce a periodic response, apparently, so that signal-averaging techniques may be used to (a) diminish the total quantity of data stored, and (b) permit the computation of crosscorrelation and Fourier-transform functions as discrete sums of a reasonably finite number of terms.162,163... 

When picking a solvent there are several considerations. First, and most obvious, the solvent must be inert, and it must dissolve the sample Of course, if your sample is sparingly soluble or if there is only a fraction of a milligram of sample available, you can usually resort to signal-averaging techniques to obtain the desired S/N. Besides that, it is best if the solvent does not contain any nuclei of the isotope to be examined. 

To improve the dynamic range (DR) achievable in an interferogram, signal-averaging techniques must be used. The dynamic range is defined as... 

The detection sensitivity of the experimental arrangement is defined by the minimum absorbed power that can still be detected. In most cases it is limited by the detector noise and by intensity fluctuations of the radiation source. Generally, the limit of the detectable absorption is reached at relative absorptions AP/P > 10 -10 . This limit can be pushed further down only in favorable cases by using special sources and lock-in detection or signal-averaging techniques. 

Grotjahn L, Taylor LCE. The use of signal averaging techniques for the quantitation and mass measurement of high molecular weight compounds using fast atom bombardment mass spectrometry. Org Mass Spectrom. 1985 20 146 52. 

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