请求帮助。。。。...

<p>我高不董FLUKE－4300的RL，NEXT,这个数值表示什么？？？？？</p><p>求各位高手帮助，&nbsp; 谢谢！！！！！！</p>

<p>RL：回波损耗</p><p>NEXT：近端串扰</p>

<p>&nbsp; </p><p><font face="黑体"><font color="#000000"><span style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">　回波损耗</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;">(RL)</span><span style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">是测量因阻抗不匹配引起的信号反射。</span><span style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">产生阻抗不匹配的原因有以下几种：</span></font></font><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><br/><br/><font face="黑体" color="#000000">? </font></span><span style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;"><font face="黑体" color="#000000">　双绞线质量差</font></span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><br/><font face="黑体" color="#000000">? </font></span><span style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;"><font face="黑体" color="#000000">　不同厂家不同类型的线缆不匹配</font></span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><br/><font face="黑体" color="#000000">? </font></span><span style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;"><font face="黑体" color="#000000">　线缆连接硬件不匹配</font></span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><br/><font face="黑体" color="#000000">? </font></span><span style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;"><font face="黑体" color="#000000">　接头位置双绞线变形</font></span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><br/><font face="黑体" color="#000000">? </font></span><span style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;"><font face="黑体" color="#000000">　线对分离，来自其它金属线或屏蔽层的影响</font></span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><br/><font face="黑体" color="#000000">? </font></span><span style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;"><font face="黑体" color="#000000">　外力对线缆束挤压变形</font></span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #006677; FONT-FAMILY: Verdana; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><br style="mso-special-character: line-break;"/><br style="mso-special-character: line-break;"/></span></p><p>测试仪通过在一对绕对上加测试信号并测量其他电缆绕对接收到的串扰信号测试next(近端串扰)。next值，用分贝表示，是在电缆同一端的测试信号及串扰信号的幅度差计算出来。高的next值反应小的串扰值和更好的电缆效能。<br/><br/>&nbsp;&nbsp;&nbsp; 所有通过电缆传输的信号都受到衰减的影响。由于衰减的存在，发生在电缆远端的串扰对next的影响就小于发生在近端的串扰。因此，要验证电缆的性能，就必须在电缆的双端测量。<br/><br/>&nbsp;&nbsp;&nbsp; </p>

谢谢楼上的朋友！！！

回答的不错