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    On 12/05/2014 10:53 AM, Juha Vierinen wrote:
    <blockquote
cite="mid:CAGbkif3dgqD=FxkZJ_oyU52_zvAqm4crR-BRZAsX-Xz95smSuQ@mail.gmail.com"
      type="cite">
      <div dir="ltr">Starttime is just a unix second about 10 seconds
        into the future. 
        <div><br>
        </div>
        <div>PPS is TTL from fanout buffer. I think the 10 MHz is +10
          dBm. This is the device: <a moz-do-not-send="true"
            href="http://www.fei-zyfer.com/cs2.htm">http://www.fei-zyfer.com/cs2.htm</a></div>
        <div><br>
        </div>
        <div>The same clock source works well with the N200. The B210 is
          kind of synchronized, but there is ~100 microseconds of random
          offset between restarts. </div>
        <div><br>
        </div>
        <div>juha</div>
      </div>
    </blockquote>
    OK, and how are you measuring those offsets?  Sample timestamps
    against outside-world events?  <br>
    <br>
    <blockquote
cite="mid:CAGbkif3dgqD=FxkZJ_oyU52_zvAqm4crR-BRZAsX-Xz95smSuQ@mail.gmail.com"
      type="cite">
      <div class="gmail_extra"><br>
        <div class="gmail_quote">On Fri, Dec 5, 2014 at 3:22 PM, Marcus
          D. Leech via USRP-users <span dir="ltr"><<a
              moz-do-not-send="true"
              href="mailto:usrp-users@lists.ettus.com" target="_blank">usrp-users@lists.ettus.com</a>></span>
          wrote:<br>
          <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
            0.8ex; border-left: 1px solid rgb(204, 204, 204);
            padding-left: 1ex;">
            <div bgcolor="#ffffff" text="#000000">
              <div>
                <div class="h5"> On 12/05/2014 08:50 AM, Juha Vierinen
                  via USRP-users wrote: </div>
              </div>
              <blockquote type="cite">
                <div>
                  <div class="h5">
                    <div dir="ltr">
                      <div>I've slowly gathered the courage to try out
                        the B210 devices. I was impressed by the fact
                        that I could get 50 MHz of bandwidth out of it.
                        However, I immediately ran into problems with
                        absolute timing. </div>
                      <div><br>
                      </div>
                      I've been using the B210 for mimo with USRP N200
                      devices for testing. The N200 devices all nicely
                      synchronize themselves to the external PPS and
                      after multiple restarts, their timing will be
                      accurate. However, the starting time of the B210
                      seems to have a random component with a standard
                      deviation of about 100 microseconds. Every time I
                      restart sampling, the offset between the N200 and
                      the B210 is slightly different. There is no change
                      in the timing offset between the N200 devices. 
                      <div><br>
                      </div>
                      <div>Is this a known issue, or am I doing
                        something wrong?  
                        <div>
                          <div><br>
                          </div>
                          <div>This is how I configure the devices:</div>
                          <div>
                            <div><br>
                            </div>
                            <div>u.set_clock_source("external")</div>
                            <div>u.set_time_source("external")</div>
                            <div>tt = time.time()<br>
                            </div>
                            <div>while tt-math.floor(tt) < 0.2 or
                              tt-math.floor(tt) > 0.3:</div>
                            <div>    tt = time.time()</div>
                            <div>    time.sleep(0.01)</div>
                            <div>print("Latching at "+str(tt))</div>
                            <div>u.set_time_unknown_pps(uhd.time_spec(math.ceil(tt)+1.0))</div>
                          </div>
                          <div>
                            <div>time.sleep(1)</div>
                          </div>
                          <div>u.set_start_time(uhd.time_spec( starttime
                            ) )<br>
                          </div>
                          <div><br>
                          </div>
                          <div>juha</div>
                        </div>
                      </div>
                    </div>
                  </div>
                </div>
                <pre><fieldset></fieldset>
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</pre>
              </blockquote>
              Where and how does 'starttime' get set?<br>
              <br>
              How are you distributing your 1PPS and 10Mhz clocks?<span
                class="HOEnZb"><font color="#888888"><br>
                  <br>
                  <br>
                  <pre cols="72">-- 
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
<a moz-do-not-send="true" href="http://www.sbrac.org" target="_blank">http://www.sbrac.org</a>
</pre>
                </font></span></div>
            <br>
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            <br>
          </blockquote>
        </div>
        <br>
      </div>
    </blockquote>
    <br>
    <br>
    <pre class="moz-signature" cols="72">-- 
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
<a class="moz-txt-link-freetext" href="http://www.sbrac.org">http://www.sbrac.org</a>
</pre>
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