  We develop an universal method to significantly suppress probe-induced shifts
in any types of atomic clocks using the Ramsey spectroscopy. Our approach is
based on adaptation of the synthetic frequency concept [V. I. Yudin, et al.,
Phys. Rev. Lett. 107, 030801 (2011)] (previously developed for BBR shift
suppression) to the Ramsey spectroscopy with the use of interrogations for
different dark time intervals. Universality of the method consists in
arbitrariness of the possible Ramsey schemes. However, most extremal results
are obtained in combination with so-called hyper-Ramsey spectroscopy [V. I.
Yudin, et al., Phys. Rev. A 82, 011804(R) (2010)]. In the latter case, the
probe-induced frequency shifts can be suppressed considerably below a
fractional level of 10$^{-18}$ practically for any optical atomic clocks, where
this shift previously was metrologically significant. The main advantage of our
method in comparison with other radical hyper-Ramsey approaches [R. Hobson, et
al., Phys. Rev. A 93, 010501(R) (2016); T. Zanon-Willette, et al., Phys. Rev. A
93, 042506 (2016)] consist in much greater efficiency and resistibility in the
presence of decoherentization.
