>>The phase of the PPSOUT and the generated 10 MHz will probably not align > up, >something which is critical to some applications. > Yes, for example the DVB-T SFN requires the PPS and 10MHz phases to be > aligned, better, not to move. This requires to slightly alter the 10MHz to > keep the PPS aligned. > > Let me ask Bjorn: did you succeed in aligning the two PRS10?
Somewhat... I had a "stable" offset between the 10MHz PRS10 signals of almost 8ns, moving +-2.5ns over some hours. Moreover, > what > do you mean by "each other", a scheme like this: > > > > |-------------------------------------------------------------------| > | | > | PRS10A PRS10B | > |--->PPS IN PPS OUT------>PPS IN PPS OUT--| > > > hoping that the font doesn't mess up the ASCII schematic... Almost, I also let the PRS10A be steered by a Tbolt. PLL settings 8 on PRS10A, and 0 on PRS10B, which should make PRS10B quick enough to follow any wiggle the PRS10A do slowly following its Tbolt supplied PPS_in. I had locked Tbolt 1PPS going into PPS_IN of PRS10A PPS Out of PRS10A going into PPS_IN of PRS10B. I watched/measured 1) PPS out from Tbolt on ch 1 (yellow) 2) 10MHz out from PRS10B on ch 2 (green) 3) 10MHz out from PRS10A on ch 3 (blue) 4) 1PPS out from PRS10 B on ch 4 (red) see attached screendump from a 500MHz Scope. I did not have enough time to completely remove offsets between 10MHz signals from PRS10A & B. More tuning should have been done on the PRS10A wrt the Tbolt PPS also. Any comments? -- Björn > On Wed, May 2, 2012 at 11:07 PM, Magnus Danielson < > mag...@rubidium.dyndns.org> wrote: > >> Hi Azelio, >> >> On 05/02/2012 10:30 PM, Azelio Boriani wrote: >> >>> Magnus, you are correct but can I avoid to list our beloved >>> counters/analyzers? The time-nut main tool is the TIC. >>> >> >> Hehe, yes. But you can do great things even with a spare HP5335A for >> instance. It's quite respectable with about 1 ns resolution in this >> context. >> >> I have not tried using the SIA-3000 for TIC purposes. Just "getting >> into" >> the machine GPIB-wise is a bit of a challenge. >> >> Anyway, to correct the PPS input for the PRS10 the hardware approach is >> a >>> must: so a delay line and a microprocessor are needed. Unless the SRS >>> can >>> develop a suitable software for the PRS10 (an inverted TTL serial line >>> is >>> already present) to read the M12+. >>> >> >> Well, look at the Spectratime SRO-100, which already has that feature. >> >> http://www.spectratime.com/products/isync/gps-disciplined/SRO-100 >> >> Architecture-wise it is very similar to the FEI 5680, a 60 MHz VCXO, DDS >> for FLL and then DDS for output. PPS input and output makes you think >> about >> PRS-10. The PPS input has about 1 ns resolution. >> >> Now, there is a few things which differs from the PRS-10. It move it's >> internal (and later also its output) PPS to align up to the PPS >> reference. >> It hence does not need an output alignment. This makes the 7,5 MHz clock >> (133 ns cycle) less critical. BTW I do the same in my products. The >> phase >> of the PPSOUT and the generated 10 MHz will probably not align up, >> something which is critical to some applications. >> >> Also, it can take info from Jupiter-T, OnCore, M12+ and SuperStar II >> receivers for detailed timing info. >> >> Cheers, >> Magnus >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >
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