On Tue, May 21, 2024 at 9:34 PM Marcus D. Leech <patchvonbr...@gmail.com> wrote: > > On 21/05/2024 21:05, Hamid Niknami wrote: > > Thank you for your reply. REgarding the write speed, I assume that fast SD;s > should be able to easily do that: > > The NVMe Gen4 x4 interface delivers extreme performance of up to 7,500MB/s > seq. read and 6,850MB/s seq. write speeds. > > Well, of course, fast disk-drives are necessarily connected to a computer, > with the attendant operating-system and > CPU bottlenecks. It's not like the SDR just directly talks to you disk > drives with no intervening "system stuff". > > > By synchronization, I mean that all three SDRs start sampling at the same > time (with less than 1us difference). > > That should be doable. > > > The questions that I have are as below: > Q1) Considering the fact that I will have a minimum of three SDRs, can one > instance of the GNU Radio running on my PC handle three or more SDRs? > > Keeping in mind *performance* considerations, that shouldn't be an issue. > Gnu Radio places each block in its own thread, > and for quirky reasons each of your B2xx blocks will need to be separate. > > > Q2) Is there any ready to use GNU Radio Flow graph for such a scheme to work? > > There may be. You could check cgran.org, or ask on the discuss-gnuradio > mailing list. But, really, the set > "useful and interesting things one might do at the intersection of radio, > DSP, and computers" is large-to-infinite. > So expecting something "out there" that does exactly the thing you want to > do is, I would say, naive. > > > Q3) Can you suggest any other low cost approach for recording and playing > back 100MHz bandwidth at 2.4GHz? > > Not immediately. But I've been an SDR guy since 2004, and a USRP guy since > shortly after that. So, that's kind of > where my head-space is at.
Hi Hamid, I will just add a few comments. 1) If you want 100 MHz bandwidth, I would highly recommend getting a model that can handle that bandwidth (such as X300, X310, etc). Although this device is more expensive than 3 B200 devices, it will be much easier and provide a fully coherent 100 MHz signal. 2) if you want to record to the PC, I would recommend recording to a RAM-drive (ramfs) if possible. This, of course, depends on whether your PC has enough RAM to hold your required number of samples. If you have enough RAM, you will have less problems (such as overflow, out-of-sequence packets) if you record to a RAM-based file and then transfer it to your SSD later. 3) if your sample depth requirement is even shorter, it is possible that the onboard device RAM could store your recording (unless you want it saved for later use). The RFNoC Replay block can record the incoming Rx signal (up to 1GB or 250MS on the X3xx, I think) which you could later play out from device RAM to the Tx path. But, this may not be as easy from gnuradio (i'm not really sure) so it might require a custom program (python or c++) using the UHD API. Rob _______________________________________________ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
