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    <div class="moz-cite-prefix">On 03/05/2019 06:01 AM, Koyel Das
      (Vehere) via USRP-users wrote:<br>
    </div>
    <blockquote
cite="mid:PN1PR01MB0720F18D6C92C1C42F76955C90720@PN1PR01MB0720.INDPRD01.PROD.OUTLOOK.COM"
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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 ofa two channel
          splitter and connected the other two ports of the splitter to
          the twoRX1 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>
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        </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>
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              <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: +9133 40545454 | F: +9133
                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
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                style="font-size:9pt"><i><br>
                </i></font></font></div>
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    </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 class="moz-txt-link-freetext" href="https://kb.ettus.com/TwinRX">https://kb.ettus.com/TwinRX</a><br>
      <br>
      <br>
       <br>
      <br>
      <br>
    </font>
    <blockquote
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