title: I cant run filesource<->uhd/any sink flowgraph on gnuradio and high samplate
body: <p>I am going to transmit the complex data produced from <strong>matlab</strong> by using <strong>usrp b210</strong> and <strong>gnuradio</strong> on windows.
  <strong>gnuradio flowgraph</strong> is following:</p>
  <p><img src="https://i.stack.imgur.com/bKM5k.png" alt="" /></p>
  <p>Here, data type is complex.
  Problem:
  I want sample-rate is <strong>20MHz or 30.72MHz,</strong> but <strong>gnuradio is stoped</strong>, logging out <em>'UUUUUUU...'</em> or <em>'UUOUUUUU...'</em>.</p>
  <p>why?, and how to fix it? please help me. thanks.</p>