Sun Nov 26 19:16:22 EST 2006
and frequency domain. Also, that the Alan deviation and phase noise plots
are the recommended performance measures to compare clocks in the respective
domains. Another cool thing is that there is an empirical link between the
two and that one can switch between the two with reasonable accuracy.
If one took two Allan deviation (or phase noise) plots one can compare two
clocks directly. Both the phase noise and Allan deviation measures are
statistical in nature and are respectively frequency and time dependent. I
also know that one can get a grip on the phase noise plot by integrating
under the curve for a specific frequency range. This answer can then be
scaled to seconds to give the integrated jitter over the frequency range
involved. What I don't understand is how does one use the Alan deviation to
predict how much a clock will drift on a certain time scale. For example,
500ps over a period of 1us. Or 1s for each day.
Initially I was convinced that the Alan deviation is very nifty because one
can easily identify the different noise types. And, of course to directly
compare clocks in the time domain. However, there seems to be an easy to
read off by how much a clock will drift after a certain period in time? It
would be much appreciated if someone could elaborate a bit on this topic. Or
point me to a previous thread that already did.
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