Hi Massoud - The 'O' and 'U' mean overflow and underrun, respectively; see also:< https://files.ettus.com/manual/page_general.html#general_ounotes >. Note that if the O/U occur regularly during runtime they -will- impact data flow; these are best avoided! Any that occur during flowgraph startup or shutdown can generally be ignored.
Whether your B210 can support bi-directional 10 MS/s or 20 MS/s or 28 MS/s depends on a number of factors, such as the quality of the USB cable, the USB chipset in the host computer, the general speed / power of the host computer to do CPU-based processing, and whatever application is generating (for Tx) and/or processing (on Rx) the data. Since you're using GNU Radio, the actual flowgraph you're executing impacts the max supported throughput: UHD will generate a 'U' for underrun on Tx if the host computer isn't supplying data fast enough to UHD (and thence to the USRP), and an 'O' for overflow on Rx if the host computer isn't consuming data fast enough from UHD (and thus from the USRP). A faster computer might help here, but a "better" flowgraph might also do the trick. You can test out pure-UHD (no GNU Radio or anything else) Tx, Rx, or Tx/Rx max rates for your setup via the UHD "benchmark_rate" example; for example: "benchmark_rate --rx_rate 2e6 --tx_rate 2e6" will test simultaneous Tx and Rx at 2MS/s each way. In this manner, you can figure out what the max rates supported by your setup are. On my setup, I can get 28 MS/s bidirectional without issues; my setup is a 2019 8-core MacBook Pro with USB-C, and the cable is high quality ... so I'm confident my overall computer setup is very capable! If, after testing with just UHD, your system can't support the your desired 28 MS/s bidirectional, then you should explore (1) a better USB cable, since they are relatively inexpensive; and then (2) a better host computer. If testing with just UHD shows good throughput, then it's a GNU Radio issue and you should explore a better GNU Radio flowgraph (whatever that might mean for your specific needs here). Hope this is useful! - MLD On Fri, Jan 24, 2020 at 3:00 AM massoud pourmandi via USRP-users < [email protected]> wrote: > Dear colleagues, > > Based on the USRP B210 datasheet, I can increase the sampling rate of the > device to 28 MS/s if I use RFA (TX/RX, RX2) ports simultaneously as > transmitter and receiver, respectively. Thought, for sampling rate greater > than 2MS/s, I start getting messages at the output terminal. I attached the > messages in the following. > > First: theses ‘O’ and ‘U’ signs, what are the meanings of these signs? > > Second: I need to be able to use the highest sampling rate of B210, should > I have to use a more powerful PC? > > I would appreciate if you explain the solutions of this issue in more > detail. > _______________________________________________ > USRP-users mailing list > [email protected] > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > -- Michael Dickens Ettus Research Technical Support Email: [email protected] Web: https://ettus.com/
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