If I recall correctly, the app has to be the same in all blocks when you use the FFT, that’s the case for the Fosphor graph anyways. Does that track with your understanding Rob?
Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ From: Rob Kossler <rkoss...@nd.edu> Sent: Tuesday, September 13, 2022 9:54:02 AM To: Minutolo, Lorenzo <minut...@caltech.edu> Cc: USRP-users@lists.ettus.com <usrp-users@lists.ettus.com> Subject: [USRP-users] Re: RFNOC4, FFT Block, Python Hi Lorenzo, The FFT block requires the number of samples per packet to exactly equal the FFT size. When the graph commits, UHD will try to resolve a packet size that all of the blocks are happy with. Perhaps if the FFT size is 2^11, this packet size may be bigger than the radio wants to deliver (or bigger than the SPP you specified in the rx_streamer, I don't really know). In my opinion, this is a really unnecessary limitation of the stock FFT block. With relatively minor changes, this block would not need any linkage between packet size and FFT length. Rob On Mon, Sep 12, 2022 at 8:20 PM Minutolo, Lorenzo <minut...@caltech.edu<mailto:minut...@caltech.edu>> wrote: Hi All, I'm using UHD 4.2 to play around with RFNOC4. I successfully added an FFT block to the XG image of an X300, no static connections. uhd_usrp_probe returns as expected. I use the attached code to test it out. When I commit the graph I get the following error: Traceback (most recent call last): File "/home/lorenzo/test_rfnoc_fft.py", line 71, in <module> graph.commit() RuntimeError: ValueError: samples per package must not be smaller than atomic item size Digging a bit in the libraries I see that it originates from rfnoc_streamer.cpp, specifically: [...] if (ais.is_valid()) { const auto spp = this->rx_streamer_impl::get_max_num_samps(); if (spp < ais.get()) { throw uhd::value_error("samples per package must not be smaller than atomic item size"); } [...] Has someone encountered this error before? Thenks, Lorenzo Attached code: args = "addr=192.168.30.2" graph = uhd.rfnoc.RfnocGraph(args) radio_ID_A = uhd.rfnoc.BlockID(0, "Radio", 0); radio_block_A = graph.get_block(radio_ID_A); radio_ctrl_A = uhd.rfnoc.RadioControl(radio_block_A) set_freq = 300e6 spp = 512 radio_ctrl_A.set_tx_frequency(set_freq, 0) tx_freq = radio_ctrl_A.get_tx_frequency(0) radio_ctrl_A.set_rx_frequency(set_freq, 0) rx_freq = radio_ctrl_A.get_rx_frequency(0) print("Tuning is TX %.1f, RX: %.1f MHz" % (tx_freq/1e6,rx_freq/1e6 ) ) radio_ctrl_A.set_properties(f'spp={spp}', 0) radio_ctrl_A.set_rx_antenna('RX2',0) radio_ctrl_A.set_rate(200e6) DDC_ID = graph.find_blocks("DDC")[0] DDC_block = graph.get_block(DDC_ID) DDC_control = uhd.rfnoc.DdcBlockControl(DDC_block) DDC_control.set_input_rate(200e6, 0) DDC_control.set_output_rate(5e6, 0) FFT_ID = graph.find_blocks("FFT")[0] FFT_block = graph.get_block(FFT_ID) FFT_control = uhd.rfnoc.FftBlockControl(FFT_block) FFT_control.set_length(spp) FFT_control.set_magnitude(uhd.libpyuhd.rfnoc.fft_magnitude.COMPLEX) FFT_control.set_direction(uhd.libpyuhd.rfnoc.fft_direction.FORWARD) FFT_control.set_shift_config(uhd.libpyuhd.rfnoc.fft_shift.REVERSE) stream_args = uhd.usrp.StreamArgs('fc32','sc16') stream_args.args = 'spp='+str(spp) rx_stream = graph.create_rx_streamer(1, stream_args) graph.connect( radio_ID_A,0, DDC_ID,0, False ) graph.connect( DDC_ID,0, FFT_ID,0, False ) graph.connect( FFT_ID,0, rx_stream,0 ) graph.commit() _______________________________________________ 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>
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