discuss-gnuradio
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Discuss-gnuradio] Issues with syncing two USRPs!


From: khalid.el-darymli
Subject: [Discuss-gnuradio] Issues with syncing two USRPs!
Date: Tue, 10 Jun 2014 17:39:12 -0230

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, <address@hidden> wrote:
Send Discuss-gnuradio mailing list submissions to
        address@hidden

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
        address@hidden

You can reach the person managing the list at
        address@hidden

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)





reply via email to

[Prev in Thread] Current Thread [Next in Thread]