Björn,

On 05/03/2012 12:42 AM, [email protected] wrote:
Yes, all made clear.
Trigger on Ch.4, I see. You have written "green: 10MHz PRS10B" but it must
be A, otherwise it seems that the PPS and the 10MHz of the PRS10 are not
phase aligned. Moreover, the PRS10B seems to track the PRS10A with "some
delay" as the 10MHz from A spreads on more than 5nS (useful, the infinite
persistence, isn't it? I use it a lot)



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 PRS10A on ch 2 (green)   // Corrected
     3) 10MHz out from PRS10B on ch 3 (blue)    // Corrected
     4) 1PPS out from PRS10 B on ch 4 (red)

I should do some proper measurements with TIC, instead of just 'watching'
on the scope. Yes the 1pps and 10MHz is ofcause stable within the same
PRS10. But should not the 10MHz zero crossing be aligned with the 1PPS?

No. See my other posting. As far as I can see, the PRS-10 does not bother to create relative phase alignment between 10 MHz and PPS. If you want that, you will have to play tricks with the time-offsets (TO) with the hints from the time-tags (TT) and then some separate calibration.

It seems like there is still some time-offset calibration to be done.

Cables were not perfectly matched, but should be within 2-3ns of each
other.

Yes, persistance is very nice!

Indeed. For stuff like this, I like having a scope in parallel with the signals so I see what happens. The counter gives the quality measures, but the scope gives the overall picture and you get such a more direct response of behaviour as you see the PPS move about.

Cheers,
Magnus

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