Are you talking about the gain of the “RFNoC Rx Radio” block or a software gain block before the FFT? Even with the highest possible hardware gain it doesn’t seem to work.
Von: Marcus D. Leech <patchvonbr...@gmail.com> Gesendet: Montag, 21. August 2023 16:49 An: usrp-users@lists.ettus.com Betreff: [USRP-users] Re: RFNoC: strange behavior of FFT block On 21/08/2023 09:04, Bachmaier, Luca wrote: Hello everyone, I’m currently running into issues while trying to use the RFNoC FFT block in GNU Radio. A picture of my GNU Radio flowgraph and its QT GUI Vector Sink output are attached. The configuration of UHD / my USRP should be correct as there are no problems when I stream the RFNoC RX Radio Data to my host and calculate the FFT on the host. However, when I try calculating the FFT on the FPGA, the output seems to make no sense. I can’t see a noise floor or any proper signals. There’s just a randomly appearing and disappearing DC spike. Other than that, the spectrum is just a flat line (see vector_sink.png). I think that this problem comes from some faulty configuration of the RFNoC FFT block. Unfortuantely, I haven’t been able to find any helpful and up-to-date information about its usage online. I would be very glad to get some help from this mailing list. Thank you and regards Luca _______________________________________________ USRP-users mailing list -- usrp-users@lists.ettus.com<mailto:usrp-users@lists.ettus.com> To unsubscribe send an email to usrp-users-le...@lists.ettus.com<mailto:usrp-users-le...@lists.ettus.com> You could try increasing the gain--it may be that due to the integer implementation of the FFT, the signal levels are dropping below the minimum quantization.
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