[USRP-users] Usrp Gain Settings

Marcus Müller marcus.mueller at ettus.com
Wed Oct 15 04:25:52 EDT 2014


Hello Paul,

On 14.10.2014 02:34, drpaulcreaser via USRP-users wrote:
> Hi
>
> I currently have a usrp x310 with a sbx daughter board.
>
> Using the uhd driver, I can set the transmission and reception gains. 
>
> I assume there are two gain types on the usrp:
>
> 1 Daughter board- ADC gain
> 2 Digital Gain which may occur in the fpga. 
Your assumptions are accurate. Actually, on some daughterboards you even
have multiple stages of amplification and UHD distributes gain optimally
by itself (minimizing noise figure).
> I am assuming the software/firmware automatically splits the gain between gain types.
>
> Another assumption I am making is the gain is fixed. There is no AGC functionality?
On the SBX there is no AGC functionality, as AGC is inherently
application specific (e.g. your AGC needs to be significantly slower
than your amplitude modulation).
> Are these assumptions correct? I come from a software engineering background, so apologies if these questions are a bit basic.
Rest assured that those are good questions and especially your question
regarding splitting gains shows you have understanding of the technology
at hand ;)

Greetings,
Marcus




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