Tests Of Hidden Periodicities In Nongaussian Noise

We will discuss the problem of ascertaining the number of sinusoids in nonGaussian noise environment! Most tests of significance for the existence of .qinusoids are based on second order statistics. S&h testing procedures include Fisher's test, Batitlett's test, whittle's test among others. We will~ use information contained in the higher order (third and fourth) spectral function as well as second orber spectral function to form more powerful tests. Some asymptotic resullts are discussed. The question of signal to noise ratio with respect to the sample size are considered. Simulation example and sunspot data are used tO demonstrate the e~fectiveness of the methods.