<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>L. Peselnick</dc:contributor>
  <dc:creator>Huaibao P. Liu</dc:creator>
  <dc:date>1986</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;For amplitude and phase response calibration of moving-coil electromagnetic geophones two parameters are needed, namely, the geophone natural frequency,&amp;nbsp;&lt;/span&gt;&lt;i&gt;f&lt;/i&gt;&lt;sub&gt;0&lt;/sub&gt;&lt;span&gt;, and the geophone upper resonance frequency&amp;nbsp;&lt;/span&gt;&lt;i&gt;f&lt;/i&gt;&lt;sub&gt;u&lt;/sub&gt;&lt;span&gt;. The phase-ellipse method is commonly used for the in situ determination of these parameters. For a given signal-to-noise ratio, the precision of the measurement of&lt;/span&gt;&lt;i&gt;f&lt;/i&gt;&lt;sub&gt;0&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and&lt;/span&gt;&lt;i&gt;f&lt;/i&gt;&lt;sub&gt;u&lt;/sub&gt;&lt;span&gt;&amp;nbsp;depends on the phase sensitivity,&amp;nbsp;&lt;/span&gt;&lt;i&gt;f(δφ/δf)&lt;/i&gt;&lt;span&gt;&amp;nbsp;For some commercial geophones&amp;nbsp;&lt;/span&gt;&lt;i&gt;f(δφ/δf)&lt;/i&gt;&lt;span&gt;&amp;nbsp;at&lt;/span&gt;&lt;i&gt;f&lt;/i&gt;&lt;sub&gt;u&lt;/sub&gt;&lt;span&gt;&amp;nbsp;can be an order of magnitude less than the sensitivity at&lt;/span&gt;&lt;i&gt;f&lt;/i&gt;&lt;sub&gt;0&lt;/sub&gt;&lt;span&gt;. In this paper we present an improved phase-ellipse method with increased precision. Compared to measurements made with the existing phase-ellipse methods, our method shows a 6- and 3-fold improvement in the precision, respectively, on measurements of&amp;nbsp;&lt;/span&gt;&lt;i&gt;f&lt;/i&gt;&lt;sub&gt;0&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and&lt;/span&gt;&lt;i&gt;f&lt;/i&gt;&lt;sub&gt;u&lt;/sub&gt;&lt;span&gt;&amp;nbsp;on a commercial geophone.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1111/j.1365-2478.1986.tb00480.x</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Wiley</dc:publisher>
  <dc:title>Improved phase-ellipse method for in-situ geophone calibration</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>