It is shown that a useful generalized linear filter W can be construct
ed from experimental data. The data are divided into many experiments
and this ensemble is used to calculate the autocorrelation functions w
hich appear in W. In turn, from this filter one determines a ''Hamilto
nian'' H. The eigenvectors and eigenvalues of this Hamiltonian are eva
luated. For a ''good'' experiment there is one small eigenvalue, and t
he rest are approximately 1. The W' so determined usefully reduces the
noise in a new data set. The presence of two or more small eigenvalue
s indicates that the experimental data contains more than a single sig
nal. The action of W on selected members of the ensemble, and/or new d
ata sets, extracts the different signals with, again, a useful noise r
eduction. Both computer simulations and real positron annihilation dat
a are used to illustrate these developments.