SINAD SNR sinus wave NI 6733

[Mystogan]

hi everyone,

maybe this question is a bit too much, since I've seen there already too many posts regarding SNR and SINAD in this forum. But honestly, I've been looking to all the threads, and I couldnt find what I really need, thats why I'm posting this however.

My question is, how do I get the real SNR or SINAD from sinus wave from analog output PXI-6733. I've tried to look at example Basic SINAD measurement, and also niScope EX Fetch Forever using PXI-5105, but I don't think I get the real SINAD value just using simply SINAD measurement block. I'm getting only 38dB SINAD while using 1MHz sample rate and 100k points per fetch. Im geneating 10kHz sinus wave with PXI 6733 with example Cont Gen Voltage Wm-Int Clk.vi.

Any idea what do I miss here?

[Mystogan]

I couldnt upload more than 3 files in 1 post.

Maybe you'll need this to test the Cont Gen Voltage Wfm-Int Clk1.vi

regards,

Yan.

[Mystogan]

hi,

just want to correct something, SINAD I'm getting with the given setup is not 38dB, but 50dB. But still, I think its not good enough.

regards,

Yan.

[Mystogan]

still waiting :S

[Mystogan]

hi everyone,

have I posted this question in the wrong sub-forum? Should I post in other sub-forum (Multifunction DAQ) and delete this one?

regards,

Yan.

[Duffy2007 · Accepted solution]

Hi Mystogan,

if i understand you correct, you generate a sine with the PXI-6733 and measure this signal back

with the PXI-5105 and the expected value is not reached because you only get measurements

round about 50 db?

The problem could be that in manual of the PXI-5105 page 7 the SINAD of the device is between 50 - 62 db,

if you want receive better result, you should use a better card like the PXI-5122 page 9 the range is here

89 - 102 db.