Re: [Discuss-gnuradio] Ettus E310 & MIMO -- data rate?
Hi Marcus and Johannes, Thanks for your replies!! I fear that I'll have to change platform then -- I was targeting 2 x 9.1428MHz, but this is clearly going to be impossible :( Thanks again and have a nice day! Rob On Tue, 26 Feb 2019 at 16:35, Müller, Marcus (CEL) wrote: > Hi Johannes, Hi Rob, > On Tue, 2019-02-26 at 15:00 +, Johannes Demel wrote: > > Hi Rob, > > > > > (1) I cannot set an arbitrary sampling rate (for instance 9.1428M), > but > > > I am required to set e.g. 4M. > > > > USRPs, like every hardware, is constraint in terms of available sampling > > rates. You should stick with power of 2 divides of the master clock > > rate. Otherwise, the CIC filters on the USRP will corrupt your signal. > > > > While that's true, it's omitting the important point, maybe: The E310 > has a very flexible master clock rate. So, from the top of my head, > 9.1428 MHz could be possible, but only if you set the MCR to a multiple > of that first. > > > > (2) even with small sampling rates (like 2M), and despite a 10MB > buffer > > > in between the USRP source and the ZMQ sink, the system keeps > overflowin > > > > That's not very surprising. The Zynq's architecture makes it very hard > to keep both the USRP sample interface and the network interface afloat > at the same time. > > All in all, the E310 has not a great CPU, and what needs to be done > should be done on the E310 until the data rate is really low. > > This might imply that multi-MHz bandwidth applications need FPGA > design. > > Best regards, > Marcus > > ___ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Ettus E310 & MIMO -- data rate?
Hi Johannes, Hi Rob, On Tue, 2019-02-26 at 15:00 +, Johannes Demel wrote: > Hi Rob, > > > (1) I cannot set an arbitrary sampling rate (for instance 9.1428M), but > > I am required to set e.g. 4M. > > USRPs, like every hardware, is constraint in terms of available sampling > rates. You should stick with power of 2 divides of the master clock > rate. Otherwise, the CIC filters on the USRP will corrupt your signal. > While that's true, it's omitting the important point, maybe: The E310 has a very flexible master clock rate. So, from the top of my head, 9.1428 MHz could be possible, but only if you set the MCR to a multiple of that first. > > (2) even with small sampling rates (like 2M), and despite a 10MB buffer > > in between the USRP source and the ZMQ sink, the system keeps overflowin > > That's not very surprising. The Zynq's architecture makes it very hard to keep both the USRP sample interface and the network interface afloat at the same time. All in all, the E310 has not a great CPU, and what needs to be done should be done on the E310 until the data rate is really low. This might imply that multi-MHz bandwidth applications need FPGA design. Best regards, Marcus smime.p7s Description: S/MIME cryptographic signature ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Ettus E310 & MIMO -- data rate?
Hi Rob, Am 26.02.19 um 15:51 schrieb Rob Heig: > Hi, > > I've bought an Ettus E310 board and I am trying to use it for a MIMO > project, but I am encountering several issues. > > In particular, I have created a GNU Radio design, compiled it as Python > script (as illustrated on the page > https://kb.ettus.com/Streaming_processed_data_from_the_E31x_with_GNU_Radio_and_ZMQ), > > modified it (because it was complaining due to a > TypeError: push_sink_make() takes at most 5 arguments (6 given) > error with the ZMQ sink) and scp'd to the board. > > What I've found is > (1) I cannot set an arbitrary sampling rate (for instance 9.1428M), but > I am required to set e.g. 4M. USRPs, like every hardware, is constraint in terms of available sampling rates. You should stick with power of 2 divides of the master clock rate. Otherwise, the CIC filters on the USRP will corrupt your signal. > (2) even with small sampling rates (like 2M), and despite a 10MB buffer > in between the USRP source and the ZMQ sink, the system keeps overflowin > > The design I'm using is depicted here: https://ibb.co/GVJxwcm > > - Am I doing anything wrong? > - What is the sampling rate I am supposed to achieve? > > Thanks a lot in advance! > Best, > Rob > > ___ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Ettus E310 & MIMO -- data rate?
Hi, I've bought an Ettus E310 board and I am trying to use it for a MIMO project, but I am encountering several issues. In particular, I have created a GNU Radio design, compiled it as Python script (as illustrated on the page https://kb.ettus.com/Streaming_processed_data_from_the_E31x_with_GNU_Radio_and_ZMQ), modified it (because it was complaining due to a TypeError: push_sink_make() takes at most 5 arguments (6 given) error with the ZMQ sink) and scp'd to the board. What I've found is (1) I cannot set an arbitrary sampling rate (for instance 9.1428M), but I am required to set e.g. 4M. (2) even with small sampling rates (like 2M), and despite a 10MB buffer in between the USRP source and the ZMQ sink, the system keeps overflowing. The design I'm using is depicted here: https://ibb.co/GVJxwcm - Am I doing anything wrong? - What is the sampling rate I am supposed to achieve? Thanks a lot in advance! Best, Rob ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
