range or with peculiarities of used periodogram method described above. To search the periodic emission from X-ray pulsars in Prognoz 9 and GRIF “Mir” experiments it is necessary to analyze the frequency spectra in the range of small periods comparable with the duration of one telemetric data output record. In such a way the number of bins in trial period $T$ was chosen constant and equal 20 only for the large period values (more than $20\Delta t$, where $\Delta t$ is the time of one output record), while for periods shorter than $20\Delta t$ the number of bin was chosen equal to the ratio $T\over \Delta t$ rounded off to the nearest integer. The mean phase profiles constructed with such dividing on bins allow to obtain the pulsation profile in details and provide the sufficient elimination of random component. The minimal trial period for all periodograms and frequency spectra was equal $5\Delta t$. The analyzing time sets are the numbers of count rate values averaging actually for the time from the beginning to the end of an output telemetric record. These count rate values correspond to all intermediate time moments of the record but not only to one of them. 