Hello Jonathan, On Sunday, July 10, 2005 at 10:59:54 AM +0100, Jonathan Buzzard wrote:
> Depending on your serial port it will be going from ground to > something close to 10V, but the switch point between a zero and one is > around 1.5V. Hence the leading edge of the pulse is detected quicker > than the trailing edge. How much delay does this effect add? Is it stable? People with reverse polarity boards should use another time1 offset? > On Sat, 09 Jul 2005 12:04:23 +0200, Serge Bets wrote: >> pulses that should be in theory 100 ms (or 200 ms), when seen by >> "radioclk -t" are always shorter, around 92.9 ms (or 190 ms). > I considered it basically unimportant, as it is pretty much constant. And anyway in normal operations radioclk 1.0 doesn't care about precise pulse lenght nor falling edge. > For meaningful statistics in addition to the min/max/mean you need to > know what the standard deviation of the pulse lengths is. Redone stats on new data, always in µs. Longer 1 pulses lenght seem more accurate and stable than shorter 0 pulses: | 0 values=1157, min= 87930, max= 97234, mean= 93021, stddev=1794 | 1 values= 476, min=185793, max=194271, mean=189817, stddev=1389 > the idea is to make a cheap, *SIMPLE TO CONSTRUCT*, reliable device > that provides performance that at least matches other radio clocks. In > my opinion all design goals have been met, and performance of the > device outstrips almost all other radioclocks. I fully agree. I'm very happy with your project. It permited to a complete electronics illiterate that is also a poor man, me, to build a very good refclock with it's own fingers and be proud of it. And total cost of pieces was 17.27€ only. Mostly 10.76€ for the Conrad receiver, 4.40€ for the cable, 1.10€ for the DB9 connector, plus other components. And I have left some cable and components to build a second refclock, the day I can find an MSF receiver. Unfortunately near impossible to get those here, even online. BTW a bug report: radioclk 1.0 will not deal nicely with the added leap second next December 31. Serge. -- Serge point Bets arobase laposte point net _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
