|Abstract: ||A method involving the non-destructive testing of a sample electrical or
electronic device is provided. The method includes measuring a power
spectrum of the device and performing a Principal Component Analysis on
the power spectrum, thereby to obtain a set of principal components of
the power spectrum. The method further includes selecting a subset
consisting of some of the principal components, and comparing the subset
to stored reference data that include representations in terms of
principal components of one or more reference populations of devices.
Based at least partly on the comparison, the sample device is classified
relative to the reference populations.