Thanks Paul,
After re-reading my original email, it was a bit misleading.  The streaming
samples are never coming to the host - they are just looped from Rx to Tx
on the FPGA.  Thus, I can't determine the digital power on the host.  I'm
guessing that the probe signal block you mentioned operates on the host
rather than the FPGA.  I'm looking for some simple power detector that may
be part of the RFNoC radio block or DDC block that I could query
occasionally from the host to determine the digital signal power level.
Rob

On Thu, Sep 1, 2022 at 1:39 PM Paul Atreides <maud.dib1...@gmail.com> wrote:

> Hey Rob:
> If you use GNURadio, The probe signal block can take in a stream and the
> function probe block can poll The level on a time interval that you set in
> the block. Then you can use that changing variable elsewhere in the
> flowgraph to adjust the gain.
>
> <end transmission>
>
> > On Sep 1, 2022, at 10:46, Rob Kossler <rkoss...@nd.edu> wrote:
> >
> > 
> > Hi,
> > I am interested in implementing a relatively simple repeater application
> on the X310 and E310. I ran the Ettus rfnoc_radio_loopback example and this
> is nearly a perfect fit for the functionality I want. However, I am
> wondering how my application can intelligently set the Rx Gain & Tx Gain.
> Actually, the Tx gain is easy: I can leave it fixed or I can change it
> inversely with the Rx gain to maintain constant loop gain.  But, the Rx
> Gain I would like to set based on input signal power.
> >
> > I'm not thinking of a fast AGC or even logic residing on the FPGA at
> all. I'm thinking more along the lines of the host PC occasionally querying
> an "rssi" or other digital power estimate and then changing the Rx gain in
> response.  I don't care about actual power levels - I just want to maximize
> the digital dynamic range.
> >
> > I know that I can implement a custom RFNoC block that simply passes
> samples through while computing this estimate such that it can be queried
> with a register read. But, before doing so, I'm wondering if something
> already exists such that I wouldn't have to do so.
> > Rob
> > _______________________________________________
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>
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