Measuring self noise of ADCs

[ASIM_BHATTI]

Hello all

Is there any standard procedure with which we can practically measure self noises of NI PXI /non PXI based DAQ (ADC) cards please?

Regards

Asim

[amckittrick]

Hi Asim,

All National Instrument DAQ devices should have an accuracy rating within their specification sheet that factors in noise. Is there a reason that you want to specifically measure this instead of using the information from the specification sheet?

Thanks,

Andrew M.

[ASIM_BHATTI]

Dear Andrew

It is requirement of our project to measure individually self noise level of each component including NI ADC Cards

Best Regards

asim

[Henrik_Volkers]

Noise is of stochastic nature ...  

There is no unique truth.

common ways:

- capture a declaired number of samples and make a histogram 

- measure Peak to Peak Noise  (IIRR about 3x RMS noise)

I had a look at the NI5922 calibration procedure, an adaption:

Connect a imput impedance matching your task, (1M or 50Ohm resistor ?)

configure your Task (for every SR used)

capture  65536 samples

FFT

and start with the freq. bin depending of freq range and SR choosen. FFT bin 0 is the DC and should always be ignored. (That's offset 😉 )

Document the way you have choosen together with the result.