From: "Tom Van Baak" <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Positional accuracy of the M12+T Date: Thu, 4 Jan 2007 09:12:30 -0800 Message-ID: <[EMAIL PROTECTED]>
Tom, > [ sorry, let me try that again ] > > > Hmmm... with 25m position accuracy (and 100ns is > > about 30m), how do they really get time down to a > > few ns. Clever engineering! :-) > > You're comparing apples and oranges: accuracy and > stability. > > The 25 m value you often read is probably a valid > figure for the positional accuracy of an M12. > > But do not confuse this with the "few ns" timing value > you read about here. No one I know has an M12 that > is accurate to a few ns. What many of us have are > M12 that exhibit residual timing jitter of a few ns, when > properly sawtooth corrected and averaged over time > compared to a local cesium standard. > > In other words, a properly filtered M12 is *stable* to a > few ns over some time frame. But it's highly unlikely it > is *accurate* to a few ns. A couple of ten ns is much > more likely. And this is in the same ballpark as the > "25 m" positional value. Yes¸ let's not confuse our statistical deviation of samples with the accuracy in their mean. Good point there. Cheers, Magnus _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
