Hi Seshan, um, this is a bit awkward, but you wrote an email with "internal use only" to a public mailing list. Now, it's public, and due to how email works, that can't be reversed; so I might as well answer!
On 17.06.20 06:08, Seshan Govender via USRP-users wrote: > We have recently purchased a x310 and are busy testing it’s capabilities. > We would like to use the x310 to stream out and receive wideband signals at a > sample rate of 100Msps and 200Msps. Yes, that should be possible, assuming your PC is fast enough at streaming data to the device, and receiving data from the device. These rates are very high, it's non-trivial to tune your system to reliable do that, and it's even harder to do something useful with the data without completely overloading your computer! > I have connected 2 x 10Gbe, however when using the gnuradio UHD-USRP sink > with two channels, I get Underruns or Late packets error at sample rate of > 66.7Msps and above. 2 channels × 66.72 MS/s = 133.44 MS/s. That is a high rate. Your computer is simply not keeping up with the speed. > The same error happens also with the UHD benchmark tool. However, it works > with one channel, with one 10Gbe connected at a sample rate of 200Msps, with > few underruns in the beginning. That's mostly because two channels are harder to coordinate; that's not really perfect about UHD, I'd agree. > > I have the following questions: > > 1. Is it possible to achieve 2 x 200Msp with dual 10GBe without using DPDK? It should be, but I've rarely seen it work. > if so what are the necessary configurations that have to be made using > gnuradio? You have to use the DPDK-specific device address/parameter strings. > Is another image required for the x310 (other than the bit image files > downloaded from ettus) in order to enable stream on both 10GBe at the same > time? no > > 2. What is the max sample rate feasible using one 10GBe. The on-the-wire format for samples that UHD uses is complex values built from 16 bit signed integers, so 32 bit per sample. 10 Gb/s --------- ~= 0.3 GS/s = 300 MS/s 32 b/S Allow for a bit of overhead, and you can still be pretty certain that the full 200 MS/s per channel work, and that you can only do one of these channels with a single 10 Gbe link. > 3. How can we enable to stream out using dual 10GBe in gnuradio? > > 4. I tried to install DPDK also but was not successful in running it. Which > version of DPDK is recommended with uhd 3.15. What are the exact procedures > for setting up DPDK. https://kb.ettus.com/Getting_Started_with_DPDK_and_UHD > 5. It is required to transmit a band of a signal (bandwidth lower than the > sampling rate) using Gnu-radio and x310. usually, the digital bandwidth *is* the sampling rate. You're of course right, the analog bandwidths of all our daughterboards are less than 200 MHz – the UBX160 has 160 MHz of analog bandwidth. > * However, the output from the X310 is distorted as shown in the attached > file. I'm sorry, I'm having a hard time interpreting that diagram. Would you have a picture from an actual spectrum analyzer, preferrably a screenshot made with the built-in screenshotting function of that spectrum analyzer? > Also the signal is extended to the full band equal to the sampling rate. That would be indedd desirable for any rate < 160 MHz on the UBX, for example. > This happens by using 16bit integer samples.> Moreover, the signal obtained > from the X310 is different when using 12 bit int wire, the output extends the full band but is not the same as the input signal. Not quite sure I fully understand what that means. But, if you mean that the digital signal isn't faithfully restored: well, if you have underruns, your signal is broken, so anything might happen. > 6. Moreover, I want to use RFnoc with UHD 3.15, however I do not have vivado > to compile RFnoc for this version. Are there existing images for RFnoc > compatible with the latest version of UHD 3.15? We would want the RFNOC image > bit file for X310 that contains Replay block. As far as I know, no, not that I'm aware of. Best regards, Marcus _______________________________________________ USRP-users mailing list [email protected] http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
