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Externally triggered acquisition with MHz rate

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Hi,

 

I am using PCI 6110 with signal applied to one of the analog inputs and ext. trigger applied at PFI0 input of the card. I am using sampling rate as 5MSPS (max.). Labview 2011 is being used in windows pc.

 

The pulse fed to the card (to read) is having 800kHz rep rate with 180ns duration, +/-2Vpp amplitude. So roughly I have 6.25 samples between two consecutive triggers. Since the signal is within 180ns, effectively only one sample (sample just after the trigger pulse) would have information about this signal. I want to read this one sample corresponding to each ext. trigger pulse and (without skipping) such 100000 points (so for 125ms with this rate) in one go.  The basic program I use to check it is shown in the attachment.  I can get two samples: one within the pulse and the other away from the pulse  using ""analog single channel multiple sample read.vi" " for one trigger.  The problem is how to read 100000 consecutive points???? One possibility was for/while loop, which I tried but found very slow. What I did was placed read.vi inside a loop and run the loop without wait VIs. But the iteration speed of loops was very slow (only few kHz), whereas a blank loop runs with a iteration speed of 10 MHz?  Also how can one synchronize loop iterations with  ext. trigger? How can I read/record 100000 or more such samples, each one obtaied from a ext. trigger pulse. Ofcourse, the display and processing could be done after the recording to optimize time.

 

Thank you in advance.


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