[time-nuts] Speaking of Costas loops

[Dennis Ferguson]

On 3 Jul, 2013, at 11:47 , Bob Camp <lists at rtty.us> wrote:
> The pipe in this case is up on one frequency and down on another. The conversion oscillator on satellite that's the weak link, no matter how good the signal from the ground happens to be. 

That's certainly true but it doesn't seem like a problem that the
presence of a high stability free-running oscillator, like a rubidium,
would help.  The oscillator on a geostationary satellite has a
continuous frequency reference to lock to (the uplink carrier) and
hence only needs short term stability sufficient to track this and
transfer it accurately to the downlink.  It seems like this is the
kind of problem that quartz excels at.

Dennis Ferguson