power measurement with USRP

[mathias19100]

Hello,
I am trying to measure the power of a signal received in RX thanks to my USRP 2900 card. Can you help me?
I took again an example of VI provided with the drivers and modified a little. I put you my VI in appendix. I can not measure the power.
Thanks you,
MPM

[ArmandoF]

Hello mathias19100,

Before looking deeper in your VI, are you able to make the example work without any modification?
Is everything set properly in NI MAX regarding drivers and hardware detection? 

Have a nice evening,

Armando

[mathias19100]

hello Armando,

thanks you for your answer.

yes, without modification, i can run the VI and NI MAX decteted my USRP card.

I noticed, When i send a signal at 1kHz tone frequency, i measure a power at the 1kHz. But, i want measure the power at my carrier frequency.

[ArmandoF]

Hello Mathias,

Sorry for the late reply.

It looks like are you able to measure properly the signal in your VI. Do you confirm?

The VI you are using for acquiring the Power spectrum is a VI Express that may not work in your case.
Have you tried using another VI? From the Signal processing toolkit, for example.

Have a nice day,

Best regards,

Armando

[mathias19100]

Hi armando,

I can measure the Power. but when i generate a signal at -30 dBm for exemple with a signal generator, with My USRP card i measure -22 dBM. there is gain and not a loss. I do not konw why, do you have an idea ?

Thanks you,

have a nice day

Mathias

[ArmandoF]

Hello Mathias19100,

L'USRP n'est pas calibré et vous ne pouvez donc pas effectuer de mesure précise de puissance.

Vous pouvez le calibrer si vous le désirez en utilisant les outils Ettus prévus à cet effet (https://files.ettus.com/manual/page_calibration.html)

Je vous souhaite une très bonne journée 🙂

Cordialement,

Armando