Principle of a sonar or radar distance measurement
<ul><li><a href="//commons.wikimedia.org/wiki/File:Sonar_Principle_DE.svg" title="File:Sonar Principle DE.svg">Sonar_Principle_DE.svg</a>: Georg Wiora (<a href="//commons.wikimedia.org/wiki/User:Xorx" title="User:Xorx">Dr. Schorsch</a>)</li>
<li>derivative work: <a href="//commons.wikimedia.org/wiki/User:Ssola" title="User:Ssola">Ssola</a> (<a href="//commons.wikimedia.org/wiki/User_talk:Ssola" title="User talk:Ssola"><span class="signature-talk">talk</span></a>)</li></ul>
CC BY 3.0
<ul><li><a href="//commons.wikimedia.org/wiki/File:Sonar_Principle_DE.svg" title="File:Sonar Principle DE.svg">Sonar_Principle_DE.svg</a></li></ul>