Hi Farnaz, A couple of remarks and questions - Remark 1: in order to get 200 MS/s transmit streaming, you will NEED to have the samples on the USRP. The host-to-USRP streaming does not work at 200 MS/s for the transmit case (unless something has recently changed). The host-to-USRP max for transmit is 100 MS/s per channel - Remark 2: that leads into your question about having the samples stored on the USRP rather than streamed from host. This is not presently a capability, but can be added with some modest FPGA work. I have been desiring such capability for a couple of years - I hope that Ettus adds such capability in the future. - Question 1: why do you plan to use a 10gbe switch with a single connection to the host PC? Why not have multiple 10Gbe links at the PC which connect to each USRP individually. A NIC such as Intel XL-710 provides 4 10gbe links.
Rob On Thu, Jul 26, 2018 at 12:13 PM Farnaz Chamanzadeh via USRP-users < usrp-users@lists.ettus.com> wrote: > Dears, > > To be more specific, we want to control multiple USRPs with one (remote) > computer. We would like to stream known and periodic signal from each USRP. > The sequence on each USRP is unique and is different from other USRPs. > > Since the samples from each USRP are known, it would be more > convenient if we can generate the samples once and preferably store them > locally on each USRP. In this configuration, we want to use the host > computer to send control commands to the USRPs specifying when each of them > must transmit its specific samples. The USRPs are assumed to be > synchronized, so the control commands from the host will generate a TDMA > scheme. Each USRP will start signal transmission upon receiving the control > command from the host computer. I would like to know that: > > 1. Is it possible to store the samples on the USRPs? or should we stream > the samples from the host computer to the USRPs for each transmission? > 2. Can we use the full bandwidth and 200MS/s in this setup? > 3. After knowing the answer to the previous question, I would like to > know how we can implement it? do you happen to have a demo or an example > that can guide us in this implementation? > > Best, > Farnaz > > > > > > > On Wed, Jun 27, 2018 at 4:50 AM, Michael West <michael.w...@ettus.com> > wrote: > >> Hi Farnaz, >> >> To clarify and expand on Marcus' comments, the answer is maybe. You can >> do burst captures and transmissions at full rate and you can even use timed >> commands to synchronize them, but there are limitations. If you can >> describe in more detail what you want to do, we can more clearly tell you >> if it is possible. How many channels do you plan to do simultaneously? >> How many 10 GbE connections between the host and switch? How many 10 GbE >> connections between each USRP and the switch? >> >> There is buffering of the TX samples on the X310 and it is configurable. >> The current default is 32 MB. The DRAM is a total of 1 GB, and it can be >> divided up however necessary. >> >> Regards, >> Michael >> >> On Mon, Jun 25, 2018 at 12:23 PM, Marcus Müller via USRP-users < >> usrp-users@lists.ettus.com> wrote: >> >>> Dear Fernaz, >>> >>> you can't cheat 10Gig bandwidth! If you time-share any medium, then >>> it's bandwidth must be shared. Since ethernet is de facto a timesharing >>> thing, anyway, no, this won't work: >>> Since you need to push through all the data through a single 10GigE >>> connection, your 10 gigabits per second need to be divided along *all >>> simultaneously operating* USRPs. So, if you have, say 10 USRPs, and all >>> should be working at the same time, you've only got 1 gigabit per >>> second per USRP, which limits you to about 25 MSample/s per USRP. It's >>> really the same principle as a single internet access being shared by >>> all people attached to the same router. >>> >>> Now, if these USRPs *don't* have to transmit all at the same time, then >>> more is possible. >>> >>> > Also, does anyone know if it is possible to store the samples on the >>> transmit USRPs? >>> >>> I'll go with a: no, at least probably not like you hope it is. Can you >>> elaborate on your use case? Maybe we can help you if we better >>> understand what you're trying to implement, from a bit of distance? >>> >>> Best regards, >>> Marcus >>> >>> On Mon, 2018-06-25 at 20:32 +0200, Farnaz Chamanzadeh via USRP-users >>> wrote: >>> > Dear all, >>> > >>> > I want to connect multiple USRP X310 to one host PC and control them >>> > all from that Pc, using one 10Gigabit Ethernet switch. My question >>> > is that if it is possible to stream from each USRP in a different >>> > time slot using the full bandwidth and 200MS/s in a setup similar to >>> > the picture below? >>> > >>> > Also, does anyone know if it is possible to store the samples on the >>> > transmit USRPs? >>> > >>> > >>> > >>> > >>> > Best, >>> > Farnaz >>> > >>> > _______________________________________________ >>> > USRP-users mailing list >>> > USRP-users@lists.ettus.com >>> > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>> >>> _______________________________________________ >>> USRP-users mailing list >>> USRP-users@lists.ettus.com >>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>> >> >> > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >
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