Wave reconstitu​tion

Question

Hello
I am using a wave generator to simulate a 200 Hz wave and a NI acquisition board is used to acquire the signal.
I think that according to Nyquist theorem, I must, at least, acquire at 2x the frequency of the wave.
Thus, I'm acquiring, in continuous samples, at 1000Hz. I checked for different number of samples and only 20 seemed ok for wave reconstitution in excel.
When I try to acquire two waves simultaneously, (both 200 HZ) I can't seem to manage...
I'm not very confident with acquiring at high frequency...
Hope someone can help me  
I attached my vi
Thanks in advance
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Attachments:
gerador sinais 07_01_10.vi ‏342 KB

Answer 1

Hi,
When you said that you can't seem to manage, what did you mean?  Did you have an error?  Did you buffer overflow?  Some questions and comments that I have.
1. What kind of hardware do you have?  We need to know the capability of the hardware.
2. In the code, you are doing a continuous acquisition at 2k for 2 channels, 2000 samples/s/channel.  You set the number of samples to read as 200.  That means you will read 200 samples at every loop count.  What worries me is that you have a lot of analysis code in the acquisition loop.  If the analysis code slow down the loop enough, you can have a buffer overflow.  One thing that you can try is to do two parallel loops, one for acquisition and one for analysis.  From the acquisition loop, you can queue the data onto a queue structure and dequeue the data in the analysis loop. 
Yik
Kudos and Accepted as Solution are welcome!