Hi, I am a new user of USRP/GNU Radio. I am experimenting with a system comprised of one transmitter and multiple receivers. For now, I have two USRP N200. On the first USRP, I got one LFTX and one LFRX daughter boards. On the other, I got one LFRX daughter board.
In my application, it is important that the transmit and receive channels are synchronized (i.e., both device time and channel phase). For this, I am using my own GPS and PPS signals. For the sake of testing, I am feeding the output of LFTX to all the inputs in LFRX (i.e., four receive channels). The output/input type is Complexfloat32. In GRC, when I use a separate USRP source block for each motherboard (i.e., without synchronization), the system is working and I can receive four unsynchronised replicas of my transmitted signal. However, when I a use a single USRP source with two-motherboard and four-channel options, I get the following error message: linux; GNU C++ version 4.8.2; Boost_105400; UHD_003.007.001-68-gc4b1f810 -- Opening a USRP2/N-Series device... -- Current recv frame size: 1472 bytes -- Current send frame size: 1472 bytes -- Opening a USRP2/N-Series device... -- Current recv frame size: 1472 bytes -- Current send frame size: 1472 bytes -- 1) catch time transition at pps edge -- 2) set times next pps (synchronously) Using Volk machine: sse4_a_64_orc *thread[thread-per-block[4]: <block gr uhd usrp source (1)>]: RuntimeError: fifo ctrl timed out looking for acks* >>> Done My sample rate is 100e6/128 Hz. In the USRP source I set synch to: UnknownPPS, Mb0/1 clock source and Mb0/1 time source to EXTERNAL. Mb0/1 subdev spec: A:A A:B. I tried to change the WireFormat from AUTOMATIC to ComplexInt16 without any difference. I checked ./test_pps_input and I got a 'success'. I think the issue has to do with the settings for syncing. Any ideas on what causes this problem? BTW, I am also aware of this link ( http://files.ettus.com/uhd_docs/manual/html/sync.html), but I am not sure where the commands of synchronizing the device time and channel phase should be applied? Thank you. Best regards, Khalid On Tue, Jun 10, 2014 at 1:31 PM, <[email protected]> wrote: > Send Discuss-gnuradio mailing list submissions to > [email protected] > > 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 > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Discuss-gnuradio digest..." > > > Today's Topics: > > 1. Scanoo_rx: New GUI, Center Freq Hopping & SSB Modulation > (Mike Jameson) > 2. Re: Help with wx-gui, window size error (Thilina Mallawa Arachchi) > 3. Re: post_guard and pre_guard in Pecog implementation > (Vanush Vaswani) > 4. Clock block slow in position satellite calculation (caruiz.ext) > 5. Re: Clock block slow in position satellite calculation > (Marcus M?ller) > 6. CMake error (sreena p h) > 7. Re: Clock block slow in position satellite calculation > (caruiz.ext) > 8. Re: CMake error (Martin Braun) > 9. Re: Ver 3.7 stable? (Martin Braun) > 10. Re: tx_time tag accuraccy (Martin Braun) > 11. Re: Error creating block with different input signature > (Martin Braun) > 12. Re: Ver 3.7 stable? (Martin Braun) > 13. Re: DPSK demodulator computational efficiency (Kevin Langer) > 14. Time Limit (Bekir Sait ?iftler) > 15. Re: DPSK demodulator computational efficiency (Tom Rondeau) > > >
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