Re: [Discuss-gnuradio] AWGN using E310 (Update)

[John B. Wood]

Hello, all.  Perhaps I was a little too optimistic in attempting to use 
the Ettus E310 as a broadband noise source.  I'm using the GRC models 
"Fast Noise Source" with uniform noise type connected to a "UHD: USRP 
Sink" with a CF of 1 GHZ and sample rate set to 4 Msps.  Running the 
GRC-generated .py code on the E310's embedded Arm processor results in a 
reasonably flat noise spectrum over ~3.5 MHz about the CF as displayed 
on a spectrum analyzer.  Attempting to increase the sample rate above 4 
Msps to obtain a wider noise BW results in a whole lot of buffer 
underruns (all those "U"s in the terminal window and a ragged noise output.

The advertised instantaneous BW of the E310 is 56 MHz but clearly the 
available flat noise spectrum is no where near that.  As always your 
comment is most appreciated.  Sincerely,


                        John Wood
                        U.S. Naval Research Laboratory