How do you capture IQ data with RFSA vi's triggering from ext trg on digitizer?

Question

I am trying to write an application using RFSA vis that will capture IQ data when triggered from the external trigger port on the digitizer card.  This does not seem to be supported by the RFSA vis and I am not sure how to integrate ni-Scope and niRFSA in one application.

Answer 1

Hi Jltetzlaff,
The Clk in and Clk out ports on the 5142 can be used to input and
export a reference clock.  You can import this as your sample clock
source over the Clk in by using a simple property node.  This is
assuming your using LabVIEW.  My main concern is regarding your clock. 
If you take a look at page 20 of the reference manual here:
http://www.ni.com/pdf/manuals/374300c.pdf, you can see the PFI lines
follow a very specific digital logic specification (TTL).  It looks like your
signal won't be recognized properly by these lines.  The lines require
a voltage above 2.0V to register high.  There is no minimum frequency
on these PFI lines.  The problem is the logic levels.  My
recommendation would be to export a start trigger with your AWG to
begin the RFSA session.  If I'm misunderstanding the setup, could you
please give more details on devices (model numbers), development
enviroment (LabVIEW etc.), and what connections you require.  From what
I understand, you want to sync the RFSA devices with the AWG and DUT. 
Perhaps the session from the AWG that is generating the clock can also
export an event to start the AWG to start the RFSA device through PFI 0
or PFI 1.  This can be done using the niFGEN Export Signals.vi.  The
exported signals by this vi will follow the correct logic accepted by
the 5142 digitizer in the RFSA setup.
I hope this helps,
Paul C.