From: Bruce Griffiths <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Of rubidium life and piggy-bank anemia.... Date: Sun, 02 Dec 2007 09:36:14 +1300 Message-ID: <[EMAIL PROTECTED]>
> This technique creates the issue of how to correct for the effects of > deadtime. If you only switches among the sources, then you don't have a dead time as such, it is just the time between the samples. You can make measures between N sources in a repeatable fashion with a normal 2-input TIC such that you get measures between all sources. For instance, if you have 5 sources, it takes 10 measures to measure all sources against all others. You can set up them such that you access each source so that you shift from one source to another and then stay with that for the next measure. In the case of 5 sources each source would be selected and de-selected twice in each cycle. If you use RF relays or ECL muxes is a choice. For a PPS rate dividing down 5 or 10 MHz sources to 20 Hz would allow for smart edge-selection to ensure an in-window edge even with slow drift relative the others. Such a setup would give you PPS rate updates for TIC values between all sources as straight measures (i.e. not indirect relative some other source, which would only consume 4 measures for 5 sources). No dead-time. When a slip from one 20 Hz cycle to another due to phase drift occurs, it can be handled in the software post-processing. The access-pattern would make the measures not perfectly fit as well as if you had multiple TICs on the task, but it would mostly be an issue for taus near tau0. Cheers, Magnus _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
