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** Description:** The subject of research is a method of calibrating precision rubidium or cesium frequency measures. The subject of research is the calibration of precision frequency measures. The purpose of the research is the practical creation of a method (model) for calibrating of precision rubidium or cesium frequency measures with an accuracy of 1•10-12 with the help of the frequency comparator Ч7-308A/1 (range of measurement of frequencies from 5 MHz to 50 MHz, extended uncertainty of measurement of relative frequency instability, introduced by a comparator at a zero difference of input sinusoidal signals, at a confidence probability of 95% is 3•10-13), the secondary standard of units of time and frequency VETU 07-01-03-10, nominal value of the output frequency of 5 MHz, 10 MHz, 100 MHz, expanded uncertain of the measurement of the relative frequency deviation with a confidence probability of 95% is 1•10-13), using modern software, which significantly reduces the time to conduct research. As a result of the research the model and budget of calibration of precision frequency measures were obtained, as well as recommendations for the selection of points of calibration were given. The results of calibration and extended uncertainty of the frequency and time standard for СЧВ-74 were obtained. The resulting calibration model contains the following components: unknown real relative deviation of the frequency of the investigated measure, average value of the measured relative deviation of the frequency of the investigated measure, the correction due to the deviation of the indicators of the standard, the correction due to the drift of the standard since its last calibration, the correction due to the discreteness of the comparator's indicators, the correction due to the environmental impact. Conclusions and field of application of the research results: the calibration method (model) described in the article significantly reduces the time for research and can be used in any calibration laboratory, in so doing other standards can be used, depending on the accuracy required for the measurements.

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Keywords:
** calibration, frequency measures, uncertainty of measurements, frequency comparator, software

1. Mescheryak, O., Velichko, O., Shevkun, S. and Dobrolyubova, M. (2018), “Kalibrovka pretsizionnyih mer chastotyi” [Calibration of precision frequency measures], XV International Scientific and Technical Seminar “Measurement Uncertainty: Scientific, Normative, Applied and Methodical Aspects” (UM-2018): Theses of Reports, September 10, Sozopol-Kharkov, pp. 28.

2. Mescheryak, O., Velichko, O., Shevkun, S. and Dobrolyubova, M. (2018), “Kalibrovka pretsizionnyih mer chastotyi” [Calibration of precision standards of frequency], XI International Scientific and Technical Conference “Metrology and Measuring Technology”: Theses of Reports, October 9-11, pp. 194-195.

3. DP “UKRMETRTESTSTANDART” (2015), “Instruktsiia. Metrolohiia. Miry chasu ta chastoty. Metodyka povirky MPU 412/07-2015” [Instruction. Metrology. Measure of time and frequency. Method of verification. МПУ 412/07-2015], Kyiv, 4 p.

4. ZAO “VREMYa-Ch” (2014), “Komparator chastotnyiy Ch7-308A/1. Rukovodstvo po ekspluatatsii. Instruktsiya polzovatelya. Prilozhenie A (obyazatelnoe). YaKUR.411146.011-01IP” [Frequency comparator Ч7-308А/1. Manual. User's Manual. Appendix A (mandatory). ЯКУР.411146.011-01ИП], Nizhniy Novgorod, 8 p.

5. Recommendation ITU-T G.811 (1997), Timing characteristics of primary reference clocks, available at: https://www.itu.int/rec/T-REC-G.811-199709-I/en.

6. Recommendation ITU-T G.811.1 (2017), Timing characteristics of enhanced primary reference clocks, available at: https://www.itu.int/rec/T-REC-G.811.1-201708-I/en.

7. Recommendation ITU-T G.812 (2004), Timing requirements of slave clocks suitable for use as node clocks in synchronization networks, available at: https://www.itu.int/rec/T-REC-G.812-200406-I/en.

Meshcheriak, O.O., Velychko, O.M., Shevkun, S.M. and Dobroliubova, M.V. (2019), “Kalibruvannia pretsyziinykh mir chastoty” [Calibration of precision frequency measures],