Need help with settings for the FFT measurements

[Rus_K]

When I am trying to use SV kit for FFT. it already has 1000 in the sensitivity (mv/EU). What is it setting for? Whan is the reason for 1000?

Thank you

[MickeyD]

Hi Rus,

That setting is to allow you to account for any scaling you would like to set.

The default is 1000 mV assuming your engineering unit will be a volt.

If you have used DAQmx to convert your data to engineering units already. you can either remove that VI from the program. Or you can select the correct units and make the value 1 as you don't need any scaling.

If you have further questions please let me know. Posting a screenshot and the name of the VI you are using will let me explain more quickly any further questions.

Have a great day,

[Rus_K]

hello MckeyD.

I am trying to redo software that was done using DSA 4551. I am trying to measure spectrum density of the noise level using ref mic and DUT mic and then use it to calculate SNR.

Now I am using DSA 4461and SV kit rev4. I am trying to upply example from the kit SVXMPL_Baseband FFT(DAQmx). The old vi did not have any settings for sencitivity. Using 4461and 1000mV/EU I get the same SNR measurements, but wneh I look at the spectrum graph my noise level is 20db off.