E1信号直接传输能传多远

lily6189

<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">E1</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">信号直接传输能传多远</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">&nbsp;<p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">工程中经常人有会问：</span><span lang="EN-US"><font face="Times New Roman">E1</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">信号直接传输能传多远？而标准中没有给出这样的规定，如</span><span lang="EN-US"><font face="Times New Roman">ITU-T G.703</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">只提到在</span><span lang="EN-US"><font face="Times New Roman">1024KHz</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">时，设备间的损耗应不大于</span><span lang="EN-US"><font face="Times New Roman">6dB</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">。由此估算一个距离值，可以方便工程应用。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">一、先留余量</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">标准要求不大于</span><span lang="EN-US"><font face="Times New Roman">6dB</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">，考虑设计、安装、器件的偏差，余量设为</span><span lang="EN-US"><font face="Times New Roman">3dB</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">，则线的损耗应不大于</span><span lang="EN-US"><font face="Times New Roman">3dB</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">二、计算电缆的损耗</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">对</span><span lang="EN-US"><font face="Times New Roman">120</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">欧双绞线，从企业的代码中发现有以下电缆：</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt 45pt; TEXT-INDENT: -18pt; mso-list: l2 level1 lfo41;"><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Symbol; mso-font-kerning: 0pt;">·<span style="FONT: 7pt &quot;Times New Roman&quot;;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt;">120</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt; mso-fareast-language: EN-US;">Ω</span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt;">中继平衡电缆<span lang="EN-US"><span style="mso-tab-count: 1;">&nbsp;&nbsp; </span>SEYV-120-2*2*0.5P//<span style="mso-tab-count: 1;">&nbsp;&nbsp; </span>直流电阻≤97.8</span></span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt; mso-fareast-language: EN-US;">Ω</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt;">/km 绝缘电阻≥10000M</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt; mso-fareast-language: EN-US;">Ω</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt;">.km 阻抗120±15</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt; mso-fareast-language: EN-US;">Ω</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt;">@30MHz 固有衰减17.5dB/500m<p></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt 45pt; TEXT-INDENT: -18pt; mso-list: l2 level1 lfo41;"><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Symbol; mso-font-kerning: 0pt;">·<span style="FONT: 7pt &quot;Times New Roman&quot;;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt;">4芯120欧姆PCM电缆<span style="mso-tab-count: 1;">&nbsp;&nbsp; </span>CM-120-2*2*0.4sn//<span style="mso-tab-count: 1;">&nbsp;&nbsp; </span>阻抗120±15欧姆 固有衰减14.6dB/500m@1MHz<span style="mso-tab-count: 1;">&nbsp; </span><p></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt 45pt; TEXT-INDENT: -18pt; mso-list: l2 level1 lfo41;"><span lang="EN-US" style="FONT-FAMILY: Symbol;">·<span style="FONT: 7pt &quot;Times New Roman&quot;;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt;">CM-120-8*2*0.4sn，120欧双绞电缆 2.03dB/100m @ 1024kHz</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">如果假设衰减的</span><span lang="EN-US"><font face="Times New Roman">dB</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">值是与距离成线性关系，按</span><span lang="EN-US"><font face="Times New Roman">18dB/500m</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">算，则</span><span lang="EN-US"><font face="Times New Roman">120</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">欧电缆最长距离为</span><span lang="EN-US"><font face="Times New Roman">80m</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">。一般用的是第三种，一根电缆中含有八对双绞线，它的最长距离为</span><span lang="EN-US"><font face="Times New Roman">140m</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">&nbsp;<p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">对</span><span lang="EN-US"><font face="Times New Roman">75</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">欧同轴电缆，一般用的是：</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt 45pt; TEXT-INDENT: -18pt; mso-list: l2 level1 lfo41;"><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Symbol; mso-font-kerning: 0pt;">·<span style="FONT: 7pt &quot;Times New Roman&quot;;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt;">52300008, 75</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; mso-ascii-font-family: 宋体; mso-font-kerning: 0pt; mso-fareast-language: EN-US;"><font face="Times New Roman">Ω</font></span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt;">单股同轴电缆<span lang="EN-US">, SYV-75-2-1/0.32//, 外径</span></span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt; mso-fareast-language: EN-US;">Φ</span><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-hansi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 0pt;">≤<span lang="EN-US">3.4mm<p></p></span></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left;"><span style="FONT-FAMILY: 宋体;">厂家提供的实测衰减值为<span lang="EN-US">1.96dB/100m，则最长传输距离为150m。</span></span><span lang="EN-US" style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-bidi-font-family: &quot;Arial Unicode MS&quot;;"><p></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">&nbsp;<p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">综上所述，直接传输</span><span lang="EN-US"><font face="Times New Roman">E1</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">信号，最长距离大约</span><span lang="EN-US"><font face="Times New Roman">150m</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">。这个值可做为一个工程估计值，供工程人员参考。</span></p>