Re: controlling gain of USRP Sink

[Marcus D. Leech]

On 15/12/2023 15:58, Manuel Caldas wrote:
> Hi all,
>
> I am using an Ettus b200 mini for transmitting a tone at 4GHz (which 
> in turn feeds a radiometer), through a signal source block and a USRP 
> Sink. Also in my flowgraph I have a Qt GUI Range for manually setting 
> the USRPs Gain. I manually change the gain and see perfectly in a 
> fosphor sink how the power spectrum changes accordingly.
>
> What I now want to do is to make the Gain follow a gaussian evolution 
> over time (a single pulse is fine), which of course is not practical 
> nor accurate to accomplish by manually changing the gain slider.
>
> So, is there any way to achieve this? I'm using grc 3.10.8.0 (Python 
> 3.11.6) on a win 10 PC.
>
> (btw, what I am actually trying to do is to simulate the transit of a 
> radioastronomical point signal in front of an antenna, and see how my 
> radiometer responds to that).
>
> Best regards and thanks in advance!
>
> /Manuel
I would instead of changing the RF gain, change the baseband magnitude 
over time -- probably using a custom embedded
  Python block -- if the sample rates aren't too high.