Moin, Common wisdom says that you want to use a PLL to lock two oscillators together instead of an FLL, to avoid small frequency offsets or randomly shifting phase.
Almost all atomic clocks use a technique to frequency lock to an transition frequency of the atom in question. The frequency gets probed and when it's spot on, the output signal is at a maximum. This is true for the Cs beam and fountain clocks, the classical Rb, CPT designs and the passive H maser. Now, the active H maser is the only one, where the atoms are let to "oscillate" at their natural frequency and the resulting radiation is coupled out to a PLL that steers a crystal oscillator. But i've read that the passive H masers are inherently more stable than the active H masers. Could someone enlighten me why this is the case? Attila Kinali -- There is no secret ingredient -- Po, Kung Fu Panda _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.