SDR transceiver having independent mixer and ADC sampling clocks
Hi experts in SDR RF transceivers, I am working on a timing and synchronization system which generates a high-precision timing signal from a terrestrial broadcast signal. I am looking for a suitable SDR HW-board providing independent clocks for the RF mixers and the ADC. It seems that many SDR boards use transceiver chips having mixer and ADC clocks which are derived from a single clock. Thus, it is not feasible to control the ADC sampling clock frequency without affecting the mixer frequency. For example, some USRP products have Analog Devices AD9361 transceiver chips providing no option to have fully independent mixer and ADC clocks. Why would I like to have independent mixer and ADC sampling clock? The target is to generate a physical clock signal having small jitter and accurate phase. Hence, I need to control the frequency of some VCO based on the information the receiver signal processing gives. The most straightforward way to do this is to control the frequency of a VCO wherefrom the ADC sampling clock is derived. I would appreciate any suggestions about SDR HW-platforms having the capability described above. Regards, Heikki
Re: SDR transceiver having independent mixer and ADC sampling clocks
On Mon, Feb 24, 2020 at 10:39 AM Heikki Laamanen wrote: > Hi experts in SDR RF transceivers, > > > > I am working on a timing and synchronization system which generates a > high-precision timing signal from a terrestrial broadcast signal. I am > looking for a suitable SDR HW-board providing independent clocks for the RF > mixers and the ADC. > > > > It seems that many SDR boards use transceiver chips having mixer and ADC > clocks which are derived from a single clock. Thus, it is not feasible to > control the ADC sampling clock frequency without affecting the mixer > frequency. For example, some USRP products have Analog Devices AD9361 > transceiver chips providing no option to have fully independent mixer and > ADC clocks. > Is this assertion true? According to this document: https://ez.analog.com/wide-band-rf-transceivers/design-support/w/documents/10064/ad936x-local-oscillator-lo There exists 3 VCO's in the AD9361. One for TX, one for RX, and one for the baseband. Why do you believe the clocks are not independent? I agree the sampling clock might not be able to achieve the resolution you want, but I don't see why they are not fully independent already. > > > Why would I like to have independent mixer and ADC sampling clock? > > > > The target is to generate a physical clock signal having small jitter and > accurate phase. Hence, I need to control the frequency of some VCO based on > the information the receiver signal processing gives. The most > straightforward way to do this is to control the frequency of a VCO > wherefrom the ADC sampling clock is derived. > You need to be more specific regarding your jitter and phase requirements. Also remember that time is all completely relative. Lastly, what does accurate phase mean to you? Brian
gr-fosphor on AMD RX 550
Hi all, We have some new AMD machines with RX 550 graphics. I want to run gr-fosphor on them. So far I've failed to make it work. It's an AMD system with RX 550 and Ubuntu 18.04 with amdgpu open source drivers. I work with GR 3.8-master (or 3.9.0.0-git) `4f53ac5a76e3ab05960a81905a570cd74d2708d7` Since it was quite tricky for me to install OpenCL and make gr-fosphor find it, I just document my workflow really quick. I found this website: https://einsteinathome.org/content/quick-guide-how-install-opencl-amd-gpus-linux-kubuntu-1804-and-similar-distro First, I went to amd.com and got the drivers for my GPU: https://www.amd.com/en/support/graphics/radeon-500-series/radeon-rx-500-series/radeon-rx-550 Then I ran: ./amdgpu-pro-install --opencl=legacy,pal This does only install OpenCL Further, I had to install these packages on Ubuntu: libfreetype6-dev ocl-icd-opencl-dev libglfw3-dev Also, `clinfo` was useful because it gives you some info about your system. So finally, I could compile and install `gr-fosphor`. It appears in GRC and I can plug the block (Qt version) in a flowgraph. But if I run this flowgraph, I get the following error: ``` [!] gl_cmap shader compilation failed (cmap_simple.glsl) [w] Color map shader 'simple' failed to load, will use fallback [!] gl_cmap shader compile log : [!] gl_cmap shader compilation failed (cmap_bicubic.glsl) [w] Color map shader 'bicubic' failed to load, will use fallback [!] gl_cmap shader compile log : [!] gl_cmap shader compilation failed (cmap_fallback.glsl) [!] Color map shader 'fallback' failed, aborting gr::log :ERROR: qt_sink_c0 - Failed to initialize fosphor ``` I have no idea why and so far googling brought me to some macports threads that were related to Intel GPUs on MacOS. Did someone already succeed with gr-fosphor on this hardware? Do I have suitable hardware? Did I fail the installation process somewhere? Do I need to provide additional info? Cheers Johannes
GSOC 2020
Hi , My name is Narayanan and I am a second year ECE student at REC ,Chennai , India . I am interested in doing this project named "Extending and Updating gr-radar" through GSOC 2020 Program. As per the skills required I have basic knowledge in signal processing and radars. Also i am familiar with c++,python which i could code better with some guidance . I would like to know how to start working for this project .Can there be a guidance for me? Sincerely , Narayanan Vinod
[VOLK] Release v2.2.1
Hi everyone, with VOLK 2.2.0, we introduced another AVX rotator bug which is fixed with this release. In the process 2 more bugs were identified and fixed. Further, we saw some documentation improvements. ### Contributors * Clayton Smith * Michael Dickens ### Changes * Fix loop bound in AVX rotator * Fix out-of-bounds read in AVX2 square dist kernel * Fix length checks in AVX2 index max kernels * includes: rearrange attributes to simplify macros Whitespace * kernels: fix usage in header comments
Re: gr-fosphor on AMD RX 550
Hi Johannes, First off the RX550 should work just fine. I have a RX570 and run fosphor on it with no issues. I am using Ubuntu 19.10 though which is much newer kernel and newer Mesa. The OpenCL procedure looks fine and if it gets to that point, that also worked fine. For some reason the shader fail ... but it's supposed to print the error message which it's obviously not doing :/ Can you provide the full output of glxinfo and also try some open gl application / benchmark (like glmark) see if they run fine ? Cheers, Sylvain
Re: SDR transceiver having independent mixer and ADC sampling clocks
Hi "The target is to generate a physical clock signal having small jitter and accurate phase. Hence, I need to control the frequency of some VCO based on the information the receiver signal processing gives." You have the option to generate the clock entirely in digital domain because a voltage controlled clock exhibits a higher level of phase noise as com- pared to a free running clock, and hence injects more timing jitter (variation of the clock transitions around its mean value) into the system. Cheers, Qasim https://wirelesspi.com On Mon, Feb 24, 2020 at 10:02 PM wrote: > Send Discuss-gnuradio mailing list submissions to > discuss-gnuradio@gnu.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > or, via email, send a message with subject or body 'help' to > discuss-gnuradio-requ...@gnu.org > > You can reach the person managing the list at > discuss-gnuradio-ow...@gnu.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Discuss-gnuradio digest..." > > > Today's Topics: > >1. SDR transceiver having independent mixer and ADC sampling > clocks (Heikki Laamanen) >2. Re: SDR transceiver having independent mixer and ADC sampling > clocks (Brian Padalino) >3. gr-fosphor on AMD RX 550 (Johannes Demel) > > > -- > > Message: 1 > Date: Mon, 24 Feb 2020 17:38:35 +0200 > From: "Heikki Laamanen" > To: > Subject: SDR transceiver having independent mixer and ADC sampling > clocks > Message-ID: <009801d5eb28$7a78e460$6f6aad20$@dlc.fi> > Content-Type: text/plain; charset="utf-8" > > Hi experts in SDR RF transceivers, > > > > I am working on a timing and synchronization system which generates a > high-precision timing signal from a terrestrial broadcast signal. I am > looking for a suitable SDR HW-board providing independent clocks for the RF > mixers and the ADC. > > > > It seems that many SDR boards use transceiver chips having mixer and ADC > clocks which are derived from a single clock. Thus, it is not feasible to > control the ADC sampling clock frequency without affecting the mixer > frequency. For example, some USRP products have Analog Devices AD9361 > transceiver chips providing no option to have fully independent mixer and > ADC clocks. > > > > Why would I like to have independent mixer and ADC sampling clock? > > > > The target is to generate a physical clock signal having small jitter and > accurate phase. Hence, I need to control the frequency of some VCO based on > the information the receiver signal processing gives. The most > straightforward way to do this is to control the frequency of a VCO > wherefrom the ADC sampling clock is derived. > > > > I would appreciate any suggestions about SDR HW-platforms having the > capability described above. > > > > Regards, > > Heikki > > > > -- next part -- > An HTML attachment was scrubbed... > URL: < > https://lists.gnu.org/archive/html/discuss-gnuradio/attachments/20200224/52b5e327/attachment.html > > > > -- > > Message: 2 > Date: Mon, 24 Feb 2020 11:11:25 -0500 > From: Brian Padalino > To: Heikki Laamanen > Cc: GNURadio Discussion List > Subject: Re: SDR transceiver having independent mixer and ADC sampling > clocks > Message-ID: > jxu...@mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > On Mon, Feb 24, 2020 at 10:39 AM Heikki Laamanen > wrote: > > > Hi experts in SDR RF transceivers, > > > > > > > > I am working on a timing and synchronization system which generates a > > high-precision timing signal from a terrestrial broadcast signal. I am > > looking for a suitable SDR HW-board providing independent clocks for the > RF > > mixers and the ADC. > > > > > > > > It seems that many SDR boards use transceiver chips having mixer and ADC > > clocks which are derived from a single clock. Thus, it is not feasible to > > control the ADC sampling clock frequency without affecting the mixer > > frequency. For example, some USRP products have Analog Devices AD9361 > > transceiver chips providing no option to have fully independent mixer and > > ADC clocks. > > > > Is this assertion true? According to this document: > > > > https://ez.analog.com/wide-band-rf-transceivers/design-support/w/documents/10064/ad936x-local-oscil
