is absolutely necessary to know (or to estimate) exactly a noise which may be found in any analyzed data. The most problem in the procedure is the presence of anomalous magnitudes in the noise spectrum. If the signal/noise ratio is not good enough the anomalies may cause a significant variation in the parameters to be estimated.

We emphasize that a cause of the anomalies may be some residual systematic errors. In this case it is very difficult to build up a statistical model of the anomaly and the accuracy of the signal estimation may drops below a point that can be tolerated.

If the number of the anomalous harmonics is not large in comparison with the total signal harmonics, the radical solution of the problem is an exclusion of the anomalous harmonics from the analysis. If data are regular, the excluding some anomalous (in the noise spectrum) harmonics is rather safe procedure. That is because the cosmological signal and the noise are Gauss type, and the signal parameters are weakly depended on both the fact of excluding and the criteria of anomalous outliers selection (in our case we rated to anomalous the outliers beyond the 3–sigma).

But if the neglected 