Synchronize Trigger between RFSA and external signal generator

[mclim]

Hello All,

Have an RFSA consisting of PXIe5622, PXIe5603, and PXIe 5653.  Would synchronize measurment with output from and external (standalone) signal generator.  WIthin my PXI chassis, I have a PXIe6672 Timing module.  This unit will allow me to synchronize between my PXI chassis with the star configuration. 

Is not clear how to get this done.  Would like to measure within 10nS.

*) Setup RFSA for measurement

*) Setup Signal Genertor for output

*) Send trigger via PXIe6672.

       -Lag in PXI side should be negligible through the back plane.

       -Delay RFSA trigger to account for signal generator delays.

Questions:

*) Does this sound right?

*) Should I connect my signal generator to the PXI6672 output?

*) Are there other considerations I am not accounting for?

Thank you all for reading.

[Joe_S]

Hi mclim,

To synchronize your RFSA with an external signal generator, you will need to share a start trigger and a reference clock between the two devices. How exactly you would do that depends on your signal generator. You can use a trigger out or sync output from the signal generator and connect it to an input on the front panel of your RFSA to send a start trigger. Then you can route a 10 MHz reference clock from the signal generator into the PXI chassis through your PXIe-6672. It depends what kind of connections you have available on your signal generator.

Let me know if you have any follow-up questions, thanks!

Regards,

Joe S.

[anna_li]

Hi Joe,

This is Anna, I am with mclim.

Let me describe the steps we would like to do:

1) We have two PXI chassis, each one has some NI modules plugged in, each one has a timing card 6672. how are we connect these two chassis together?

2) One of the module on chassis one can issue a trigger signal, we would like this trigger to go to the external SG ( this should be easy, just put it into the trigger in at the back of the SG) and go to the NI-SA on chassis two, how will that work?

3) how are we getting the 10MHz reference connected between the two chassis and external SG?

Thank you very much,

Anna

[Lea_D]

Hi Anna,

I just wanted to follow-up on some of your questions. I'm also the applications engineer working with you on your existing service request as well.

1.)  Each timing card has a CLKOUT and a CLKIN. In order to synchronize the two chassis, we can connect the cable from the CLKOUT of one card into the CLKIN of the other card. This way both cards are using the same clocks.

2.) You can directly route the trigger from the module in chassis one to one of the PFI inputs on chassis 2. You don't need to go through the 6672 on chassis 1 at all for this. Then, in software, you can use the ConnectTriggerTerminals command. One of the parameters is the source terminal... this would be your PFI line. The other parameter is the destination terminal which would be your trigger line.

3.) Similar to the timing and synchronization card, we would physically connect the Ref Out into a splitter. Then you could take two cables and run them into the CLK IN on both 6672 cards. You would still be synchonized accross chassis, and would no longer be running a cable from CLK OUT to CLK IN. This document shows you more about that Ref Out. This explains the LO inputs. Lastly, this gives you a high-level block diagram.

Hope this helps!