Hi, Sorry about that - only have the question came through earlier. Strange..
For a while now I've got a growing interest in clocks, stability and specifically GPSDOs (mostly quartz). My education started out with the NIST Tech Note 1337. After studying the largest part of the document I felt that this was probably not a bad starting point. This document explained the various issues involved with characterizing clocks (Alan deviation and phase noise) and I bet that most of you are familiar with it. - >From latter I've learnt that clocks can be characterized in both the time 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. - Regards, - Stephan Sandenbergh _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
