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    <div class="moz-cite-prefix">On 03/05/2019 11:10 AM, Koyel Das
      (Vehere) wrote:<br>
    </div>
    <blockquote
cite="mid:MA1PR01MB0715B6200891299A8DE48CA990720@MA1PR01MB0715.INDPRD01.PROD.OUTLOOK.COM"
      type="cite">
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      Are RX1 and RX2 of RF0 controlled by same master oscillator? Will
      connecting two antennas to RX1 and RX2 of RF0, rather than to RX1
      of RF0 and to RX1 of RF1, give same phase difference between these
      two channels at every run?<br>
    </blockquote>
    All channels have their own LO.<br>
    <br>
    The TwinRx has LO sharing mode.<br>
    <br>
    <br>
    <blockquote
cite="mid:MA1PR01MB0715B6200891299A8DE48CA990720@MA1PR01MB0715.INDPRD01.PROD.OUTLOOK.COM"
      type="cite">
      <br>
      Koyel Das<br>
      Senior – Product Engineer<br>
      Vehere | Proactive Communications Intelligence & Cyber Defence<br>
      M: +919051132173 | T: +91 33 40545454 | F: +91 33 40545455 | W:
      <a class="moz-txt-link-abbreviated" href="http://www.vehere.com">www.vehere.com</a><br>
      <br>
      <br>
      <br>
      Vehere is the proud recipient of the Fastest Growing Technology
      Company Awards in India & Asia since 2012!<br>
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      any virus transmitted by this email.<br>
      <hr style="display:inline-block;width:98%" tabindex="-1">
      <div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt"
          color="#000000" face="Calibri, sans-serif"><b>From:</b>
          USRP-users <a class="moz-txt-link-rfc2396E" href="mailto:usrp-users-bounces@lists.ettus.com"><usrp-users-bounces@lists.ettus.com></a> on
          behalf of Marcus D. Leech via USRP-users
          <a class="moz-txt-link-rfc2396E" href="mailto:usrp-users@lists.ettus.com"><usrp-users@lists.ettus.com></a><br>
          <b>Sent:</b> Tuesday, March 5, 2019 7:03:42 PM<br>
          <b>To:</b> <a class="moz-txt-link-abbreviated" href="mailto:usrp-users@lists.ettus.com">usrp-users@lists.ettus.com</a><br>
          <b>Subject:</b> Re: [USRP-users] different phase difference
          using splitter on each run</font>
        <div> </div>
      </div>
      <div style="background-color:#FFFFFF">
        <div class="x_moz-cite-prefix">On 03/05/2019 06:01 AM, Koyel Das
          (Vehere) via USRP-users wrote:<br>
        </div>
        <blockquote type="cite">
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            <p style="margin-top:0; margin-bottom:0">Hi,</p>
            <p style="margin-top:0; margin-bottom:0"><br>
            </p>
            <p style="margin-top:0; margin-bottom:0">I am using USRP
              2955 R and I have connected an antenna to one end of a two
              channel splitter and connected the other two ports of the
              splitter to the two RX1 pors of USRP. I am getting
              different phase difference in each run of USRP though in
              one particular run the phase difference is constant for
              all channels. The tuned frequency is 2.4 GHz and sampling
              rate is 1 MSps so as expected that channel phase
              differences are almost same. But when I stop acquiring
              data and restart it using gnuradio or the API, then I am
              getting again a new value of phase difference across all
              channels, which is again same across channels. Is USRP so
              unstable that it gives different value of phase difference
              for each run for the same frequency, and sampling rate?
              The setup in the runs are also the same.</p>
            <p style="margin-top:0; margin-bottom:0"><br>
            </p>
            <p style="margin-top:0; margin-bottom:0">Regards,</p>
            <p style="margin-top:0; margin-bottom:0">Koyel</p>
            <p style="margin-top:0; margin-bottom:0"><br>
            </p>
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                <p style=""><font face="Tahoma,serif"><font
                      style="font-size:9pt">Koyel Das
                                                          <br>
                      Senior – Product Engineer</font></font></p>
                <font style="font-size:16px" face="Tahoma,serif"><font
                    style="font-size:9pt">Vehere | Proactive
                    Communications Intelligence & Cyber Defence</font></font><font
                  style="font-size:16px" face="Tahoma,serif"><font
                    style="font-size:9pt"><br>
                    M: +919051132173 | </font></font><font
                  style="font-size:16px" face="Tahoma,serif"><font
                    style="font-size:9pt">T: +91 33 40545454 | F: +91 33
                    40545455 | W: <a moz-do-not-send="true"
                      href="http://www.vehere.com/" target="_blank"
                      rel="noopener noreferrer" id="LPNoLP">www.vehere.com</a></font></font><font
                  style="font-size:16px" face="Tahoma,serif"><font
                    style="font-size:9pt"><i><br>
                    </i></font></font></div>
            </div>
          </div>
        </blockquote>
        <font face="Tahoma,serif"><i><br>
          </i>This isn't about "instability".  It's about the way PLL
          synthesizers work, and the fact that by default each channel
          is using its own synthesizer.<br>
          <br>
          There are a few things that need to happen:<br>
          <br>
             All the channels you're receiving need to be in the same
          multi_usrp block, which, among other things, is a conceptual
          "synchronization domain".<br>
          <br>
             Use timed-commands for tuning (which is a bit awkward to
          arrange in Gnu Radio, you'll have to modify the generated
          code).  This will arrange<br>
             for the synthesizers to be given a "resynch" signal at
          exactly the same time.<br>
          <br>
             OR<br>
          <br>
             Use the "shared LO" features of the TwinRX cards that are
          on the 2955.<br>
          <br>
          See the knowledge-base document on the TwinRX and
          phase-synchronization here:<br>
          <br>
          <a moz-do-not-send="true" class="x_moz-txt-link-freetext"
            href="https://kb.ettus.com/TwinRX">https://kb.ettus.com/TwinRX</a><br>
          <br>
          <br>
             <br>
          <br>
          <br>
        </font>
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