  We show that state-of-the-art phase noise and high frequency stability could
be simultaneously achieved in a microwave oscillator based on the
sapphire-loaded cavity resonator. The 9 GHz sapphire oscillator was constructed
with the SSB phase noise close to -170 dBc/Hz at an offset frequency of 10 kHz
and fractional frequency instability less than 2 10$^{-13}$ for integration
times from 5 to 50 s. In this work, we focus on the technique for
phase-referencing the microwave sapphire oscillator to a stable radio-frequency
source. We also discuss the suppression of the fast phase fluctuations of the
microwave signal due to its transmission through the high-Q resonator.
