Syncronise continuous analog with analog aquasition

[tomwp]

Hi I am trying to create a psuedo Vector Network Anaylser from a PCI-6110 DAQ card.  I am using one analog output to generate a continuous sine wave then detecting the amplitude and phase of the received signal on one of the analog inputs.  I am then sweeping this process across frequency to simulate a VNA.

My problem is that I need to syncronise the detection with the phase of the generated sine wave so I can measure the phase change correctly.  I can do this if I generate finite samples and trigger the acquasition from the "ao/SampleClock" but then I start acquiring from the very begining of the signal.  What I really need to do is start acquasition on the Nth cycle of the generated waveform.

[JonBowers]

You can specify a delay to get the acquisition to wait for a specified amount of time after recieving a trigger before it actually starts. You do this by setting the Start >> More >> Delay trigger property. What development environment are you using (LabVIEW, CVI, VB...)?

Regards

Jon Bowers
Applications Engineer
NI UK & Ireland

[tomwp]

Hi Jon,

I am using LabVIEW 8.20, and a PCI-6115 DAQ board.

Thanks,

Tom

[JonBowers]

Hi Tom,

If you are using LabVIEW then you should be able to use the trigger property node to set the delay time. See the attached screen shot.

Regards

Jon B  
Applications Engineer
NI UK & Ireland

[tomwp]

Excellent, thank you.