OTDR 的工作原理...

 
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR </span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">光时域反射仪</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">测试原理：</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">测试是通过发射光脉冲到光纤内，然后在</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">端口接收返回的信息来进行。当光脉冲在光纤内传输时，会由于光纤本身的性质、连接器、接合点、弯曲或其它类似的事件而产生散射、反射。其中一部分的散射和反射就会返回到</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">中。返回的有用信息由</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">的探测器来测量，它们就作为光纤内不同位置上的时间或曲线片断。</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p>&nbsp;</o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">从发射信号到返回信号所用的时间，再确定光在玻璃物质中的速度，就可以计算出距离。以下的公式就说明了</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">是如何测量距离的。</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p>&nbsp;</o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">d=(c×t)/2(IOR)<o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p>&nbsp;</o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">在这个公式里，</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">c</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">是光在真空中的速度，而</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">t</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">是信号发射后到接收到信号（双程）的总时间（两值相乘除以</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">2</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">后就是单程的距离）。因为光在玻璃中要比在真空中的速度慢，所以为了精确地测量距离，被测的光纤必须要指明折射率（</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">IOR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">）。</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">IOR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">是由光纤生产商来标明。</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p>&nbsp;</o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span>OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">使用瑞利散射和菲涅尔反射来表征光纤的特性。瑞利散射是由于光信号沿着光纤产生无规律的散射而形成。</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">就测量回到</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">端口的一部分散射光。这些背向散射信号就表明了由光纤而导致的衰减（损耗</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">/</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">距离）程度。形成的轨迹是一条向下的曲线，它说明了背向散射的功率不断减小，这是由于经过一段距离的传输后发射和背向散射的信号都有所损耗。</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p>&nbsp;</o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">给定了光纤参数后，瑞利散射的功率就可以标明出来，如果波长已知，它就与信号的脉冲宽度成比例：脉冲宽度越长，背向散射功率就越强。瑞利散射的功率还与发射信号的波长有关，波长较短则功率较强。也就是说用</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">1310nm</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">信号产生的轨迹会比</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">1550nm</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">信号所产生的轨迹的瑞利背向散射要高。</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p>&nbsp;</o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">在高波长区（超过</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">1500nm</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">），瑞利散射会持续减小，但另外一个叫红外线衰减（或吸收）的现象会出现，增加并导致了全部衰减值的增大。因此，</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">1550nm</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">是最低的衰减波长；这也说明了为什么它是作为长距离通信的波长。很自然，这些现象也会影响到</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">。作为</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">1550nm</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">波长的</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">，它也具有低的衰减性能，因此可以进行长距离的测试。而作为高衰减的</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">1310nm</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">或</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">1625nm</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">波长，</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">的测试距离就必然受到限制，因为测试设备需要在</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">轨迹中测出一个尖锋，而且这个尖锋的尾端会快速地落入到噪音中。</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p>&nbsp;</o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">另一方面，菲涅尔反射是离散的反射，它是由整条光纤中的个别点而引起的，这些点是由造成反向系数改变的因素组成，例如玻璃与空气的间隙。在这些点上，会有很强的背向散射光被反射回来。因此，</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">就是利用菲涅尔反射的信息来定位连接点，光纤终端或断点。</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p>&nbsp;</o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">换句话说，</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">的工作原理就类似于一个雷达。它先对光纤发出一个信号，然后观察从某一点上返回来的是什么信息。这个过程会重复地进行，然后将这些结果进行平均并以轨迹的形式来显示，这个轨迹就描绘了在整段光纤内信号的强弱（或光纤的状态）。下图就说明了</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">Mini-OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">的一些基本组成。</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p></o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p>&nbsp;</o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p>&nbsp;</o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p>&nbsp;</o:p></span></p>
<p style="TEXT-ALIGN: left; LINE-HEIGHT: 16.5pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt" class="MsoNormal" align="left"><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span>Mini-OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">一个最重要的性能，就是能从原有事物中进行辨别，大型的</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">，就有能力完全、自动地识别出光纤的范围。这种新的能力大部分是源于使用了高级的分析软件，这种软件对</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">的采样进行审查并创建一个事件表。这个事件表显示了所有与轨迹有关的数据，如故障类型，到故障点的距离，衰减，回损和熔接损耗。</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US">Mini-OTDR</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-family: Arial">的性能紧紧地依赖于分析软件，从而具有精确地识别事件的能力。</span><span style="FONT-FAMILY: Arial; FONT-SIZE: 12pt; mso-font-kerning: 0pt" lang="EN-US"><o:p></o:p></span></p>