On Mon, Aug 26, 2024 at 7:14 PM Olo via USRP-users < usrp-users@lists.ettus.com> wrote:
> Thank you for your detailed responses to my previous questions. I > appreciate the information provided about the limitations and potential > issues related to FFT size and TwinRX configuration. > > However, I noticed that there was no feedback regarding the YAML file I > attached in my original email. Could you please review it and let me know > if the configuration I've set up is correct? > I didn't build and test it, but if it manages to squeeze in all the IP, I see no general issues. Note that after the split block, you need to collect all the data from both outputs, meaning you need a full streaming setup. Make sure the total data doesn't exceed your link capabilities (i.e., that you are not oversubscribing your 10 GbE connection, and that your receiving computer is fast enough). > Additionally, based on your recommendations, I plan to use a window > function (Window block) with a size of 1024, along with an FFT block of the > same size for the scanner (sweep spectrum) functionality. Would this > approach be correct given the current limitations and your suggestions? > Same answer: If it fits, you're good. --M > > Your confirmation on these points would be invaluable to ensure that I am > on the right track with my project. > > Thank you once again for your time and assistance. I look forward to your > response. > > Best regards, > Olo. > On Monday, August 26th, 2024 at 18:04, Rob Kossler via USRP-users < > usrp-users@lists.ettus.com> wrote: > > > > On Mon, Aug 26, 2024 at 10:24 AM Marcus D. Leech <patchvonbr...@gmail.com> > wrote: > >> On 26/08/2024 10:21, Rob Kossler via USRP-users wrote: >> >> Hi Olo, >> On one point regarding an FFT length of 8192, there is likely an issue >> with using the Ettus FFT block. In the past (I haven't checked recently), >> this block was limited to a maximum FFT size of 1024 because the entire FFT >> had to fit in one packet where the maximum packet payload was about 2000 >> samples. It is possible to use larger FFTs, but this requires some custom >> code that divorces the FFT size from the packet size. >> Rob >> >> My understanding is that in recent RFNoC, the limit has been raised to >> 2048: >> >> >> https://files.ettus.com/manual/classuhd_1_1rfnoc_1_1fft__block__control.html >> >> The xci file > <https://github.com/EttusResearch/uhd/blob/master/fpga/usrp3/lib/ip/axi_fft/axi_fft.xci> > still shows a transform length of 1024. Also, I think that the X300 MTU > size is 10 which implies 2^10=1024 x 64bit is the max payload. This implies > 2048 32-bit words in the payload. But, because of a few bytes of header, it > is not possible to use an FFT of length 2048 unless the FFT length is > divorced from the packet length. > 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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