Measuring power using NI-USRP and Spectral measurements tool kit

[MHantera]

Hello every one 

I'm just inquiring how to calculate the power in a channel using NI USRP and SMT tool kit because I have failed calculating it using direct method so I purchased SMT so could any one help me by providing me with an example that describes how to calculate the power using spectral measurements tool kit , our he could tell me the steps that I could follow .

Thanks a lot 

[Peter_W]

Hi MHantera,

To get the channel power you would want to use the SMT Power In Band VI. You could add this to something like the NiUSRP Ex One Shot RX example VI and then feed that Magnitude Spectrum that comes out of the FFT into the Power In Band VI. Then you would just need to specify the center frequency and bandwidth for your channel and the units to return the power in. Conversely, you could start with the SMT Power In Band for niRFSA example VI (in the Example Finder) and replace the RFSA VIs with the USRP API and add in an FFT for switching to a frequency spectrum.

Best Regards,

Peter W.

[MHantera]

Thanks for your reply , I'm inquiring how to construct the power spectrum cluster such that the output from FFT is ""CDB"" only which is one element of the cluster so how to set fo or df and I'm also questioning if I could use   FFT power spectrum and PSD VI to have this cluster but here risses two questions the first one in this vi he wants me to specify  the mode either power spectrum or PSD so which one I chooses and also the second question this vi doesn't support me with the size of the window used or fft size that power inband want them so what to do 

[Peter_W]

Hi MHantera,

I don't think I'm fully understanding your most recent message. The FFT Spectrum (Mag-Phase) VI in the USRP example as well as the FFT Power Spectrum and PSD VI both output a full spectrum that already includes the f0 and df so you don't need to set those. If you're using the later you should select Power Spectrum (the default for "export mode") for the In Band measurement. Using that VI are you seeing a size limitation? What settings and sample size are you trying to use? Is it returning an error about being unable to perform the FFT or are you just not seeing the results you should? Any more information you can provide about this would be helpful.

Best Regards,

Peter W.