Oh ok, yes. I was a bit confused when I read it, but Now I understand. Yes you would have to have sample streaming to the host. I believe the FFT block has a magnitude output that you could query. It’s been a while since I looked at the code, but it was talked about at GRcon last year as a good candidate for a simple energy detector, obviously you said you wouldn’t need to detect anything so the magnitude of a signal bin vs noise bin could help find dynamic range. I’m assuming you have a known signal frequency and a known frequency which is unoccupied (noise only).
<end transmission> > On Sep 1, 2022, at 15:26, Rob Kossler <rkoss...@nd.edu> wrote: > > > 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 >> > _______________________________________________ >> > USRP-users mailing list -- usrp-users@lists.ettus.com >> > To unsubscribe send an email to usrp-users-le...@lists.ettus.com
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