<div style="margin: 12px 0px; font-family: arial; color: #333333; background: #ffffff; border: solid 4px #e5e5e5; width: 100%; clear: left;"><div class="CM_CTB_Content_Wrap" style="margin: 0px; padding: 0px;background-color: #ffffff;"><div style="border-bottom: solid 1px #dcdcdc; white-space: nowrap; margin-bottom: 8px; background-color: #eeeeee ;background-image: url(http://clipmarks.com/images/source-bg.gif); background-repeat: repeat-x; height: 24px; line-height: 24px; vertical-align: middle; padding-bottom: 4px; color: #666666; font-size: 10px;" ><a href="http://clipmarks.com/clip-to-blog/" title="see clips that are hot right now"><img src="http://content.clipmarks.com/blog_embed/ec494b95-1de7-407d-a97e-1b2740ce0054/B032F76E-2CAB-4E4F-8EA3-AA87614EB9C6/" alt="" width="19" height="19" border="0" style="vertical-align: middle; margin: 0px 4px; display: inline; border: none; float:none;" /></a>clipped from <a title="http://cnx.org/content/m12516/latest/" href="http://cnx.org/content/m12516/latest/" style="font-size: 11px;">cnx.org</a></div><blockquote style="text-align: left; padding: 0px 8px; margin: 4px 0px 8px 0px; background: transparent; border: none;" cite="http://cnx.org/content/m12516/latest/"><th class="figure-name"><strong class="title">Out of Phase Signals As Seen by a 3-Microphone Array</strong></th></blockquote><div style="height: 2px; font-size: 2px; background: #dcdcdc; border-bottom: solid 1px #f5f5f5; margin: 2px 4px;"></div><blockquote style="text-align: left; padding: 0px 8px; margin: 4px 0px 8px 0px; background: transparent; border: none;" cite="http://cnx.org/content/m12516/latest/"><img src="http://cnx.org/content/m12516/latest/figure2.jpg" alt="Out of Phase Signals As Seen by a 3-Microphone Array (figure2.jpg)" /></blockquote><div style="height: 2px; font-size: 2px; background: #dcdcdc; border-bottom: solid 1px #f5f5f5; margin: 2px 4px;"></div><blockquote style="text-align: left; padding: 0px 8px; margin: 4px 0px 8px 0px; background: transparent; border: none;" cite="http://cnx.org/content/m12516/latest/"><strong class="cnx_label">Figure 2</strong></blockquote><div style="height: 2px; font-size: 2px; background: #dcdcdc; border-bottom: solid 1px #f5f5f5; margin: 2px 4px;"></div><blockquote style="text-align: left; padding: 0px 8px; margin: 4px 0px 8px 0px; background: transparent; border: none;" cite="http://cnx.org/content/m12516/latest/"><p class="para" id="p2"> In order to determine the direction of origin of a signal, we have to add a time delay to the recorded signal from microphone that is equal and opposite of the delay caused by the extra travel time. That will result in signals that are perfectly in-phase with each other. Summing these in-phase signals will result in constructive interference that will amplify the result by the number of microphones in the array. The question is how to know what time delay to add that will produce the desired constructive interference. The only solution is to iteritively test time delays for all possible directions. If the guess is wrong, the signal will destructively interfere resulting in an diminished output signal, but the correct guess will result in the signal amplification described above. </p></blockquote></div><div style="margin: 0px 6px 6px 4px;"><table style="font-size: 11px;border-spacing: 0px;padding: 0px;" cellpadding="0" cellspacing="0" width="100%"><tr><td style="background:transparent;border-width:0px;padding:0px;">&nbsp;</td><td align="right" style="background:transparent;border-width:0px;padding:0px;width:107px" width="107"><a href="http://clipmarks.com/share/B032F76E-2CAB-4E4F-8EA3-AA87614EB9C6/blog/" title="blog or email this clip"><img src="http://content9.clipmarks.com/images/c2b-foot.png" border="0" alt="blog it" width="107" height="17" style="border-width:0px;padding:0px;margin:0px;" /></a></td></tr></table></div></div>

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