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Entry  Fri Apr 12 09:39:30 2019, Lev Pavlov, multi-board 
    Reply  Fri Apr 12 09:55:50 2019, Stefan Ritt, multi-board 
       Reply  Fri Apr 12 09:59:15 2019, Lev Pavlov, multi-board 
          Reply  Fri Apr 12 12:50:18 2019, Stefan Ritt, multi-board 
Message ID: 752     Entry time: Fri Apr 12 12:50:18 2019     In reply to: 751
Author: Stefan Ritt 
Subject: multi-board 

If you have two signal going through two cables, the cable have never the same length (on a scale of picoseconds), and you have to calibrate that anyway. So a proper timing calibration is not a crutch.

What do you mean by "manual 50ps"? The manual does not mention any resolution. In my experience, you can achieve about 10ps between channels of the SAME board easily. The phase shift between boards in multi-mode is always there, unfortunately there are no cable which conduct current faster than the speed of light! What you can do is to split a common reference clock and send a copy to one channel of each board, then calculate the timing relative to the next edge in that reference signal. This way you get rid of the phase shift, but this is also a kind of calibration, so in your laguange that would be "a big crutch".

Stefan

 

Lev Pavlov wrote:

 

I understand this, thanks. But my Chief does not understand this, he wants to see the phase difference without “crutches”. And what is meant in the manual 50 ps resolution? Maybe I just do not understand something? And if you submit a reference signal not in the mode of a garland, but simultaneously in parallel to all the boards, will this shift go? Thanks

Lev Pavlov

Stefan Ritt wrote:

Subtract 16 ns from your measured value ;-)

Stefan

Lev Pavlov wrote:

Good afternoon, I use 5 boards in multi-mode, everything is connected according to the instructions. Can I measure the phase difference between the two signals on channel 1 and channel 20? with each board the phase shift is added +16 ns I can not figure out how to compensate for this. give thanks

 

 

 

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