The LNP_TEST function computes the Lomb Normalized Periodogram of two sample populations X and Y and tests the hypothesis that the populations represent a significant periodic signal against the hypothesis that they represent random noise. The result is a two-element vector containing the maximum peak in the Lomb Normalized Periodogram and its significance. The significance is a value in the interval [0.0, 1.0]; a small value indicates that a significant periodic signal is present.
LNP_TEST is based on the routine
described in section 13.8 of
Numerical Recipes in C: The Art of Scientific Computing
(Second Edition), published by Cambridge University Press, and is used by permission.
The small value of the significance represents the possibility of a significant periodic signal. A larger number of samples for X and Y would produce a more conclusive result. WK1 and WK2 are both 48-element vectors containing linear frequencies and corresponding Lomb values, respectively. JMAX is the indexed location of the maximum Lomb value in WK2.