RFSA Averaging Mode

[HWJ]

Anyone has any idea of how the RFSA performs the averaging when you set the averaging mode to RMS or Vector Averaging?

Any weighting used on the averaging?

[Sumayyah]

Hi HWJ,

My recent encounter with an RFSA prompted me to take on your question.

So, I've found this link that might be of interest to you, take  a look:

http://digital.ni.com/public.nsf/allkb/862567530005F09C862567210074EA10?OpenDocument

I think the site has done most of the explaining. Do let me know if this is any help kay 🙂

Good luck!

Best regards,

Sumayyah, AE NI ASEAN.

[HWJ]

Hi Thanks for your reply.

May I know how this is this averaging process being performed? Is it done by the RFSA? or is it done at the controller?

Recently we encountered some memory issues when we performed spectrum acquisition on 1 x RFSA and IF Recording on another. Would like to understand more into the processing of the hardware. Thanks!

[Sastry]

Hi HWJ,

I am assuming you have Spectral Measurements Toolset. Do you? If yes, then for example, you may want to look at a vi like "SMT Averaged Power Spectrum.vi" Inside that VI you can find the subvis that do RMS Averagin, Vector Averaging, Peak Hold Averaging etc. 

Certain Factors that play the role are : 

Weighting Type : Linear or Exponential 

Linear  Weighting Mode : One-shot, Continuous, auto restart one-shot or moving average

The above factors just play the role of how many samples to hold etc.

Effectively, it is squaring the signal and then summing them. Square Root is taken or not taken based on FFT or Power Spectrum. 

I gave an answer in general RMS usage context. 

Please do let me know if the above helped or if you have any questions. 

Regards, 

Sastry