[Discuss-gnuradio] How to test and change SNR in GNURadio by B210

[Yan Huang]

Hi all,

I'm using USRP B210 to employ spectrum sensing, I want to plot ROC curve of the 
sensing output  signal. 

So I need to test and change the SNR of the receive signal. The attached 
picture is the flowgraph I use.

I choose 'MPSK USRP Estimator' to test SNR since my tx signal is BPSK. 

The problem is:

 1.why the SNR I get is nearly 0(about 10^-3)? If I increase the noise 
amplitude, the SNR increase slightly(about 10^-1), I think it will decrease as 
noise increase.

 2.Can I use  'MPSK USRP Estimator' to test SNR to test SNR in this situation? 

 3.How can I read the SNR information by using  'MPSK USRP Estimator prob'?

Many thanks in advance.

Kind regards,

Yan



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snr estimate.png
Description: snr estimate.png