专注福禄克测试仪销售与技术

直流环路电阻深度解释 – 福禄克DTX-1800和DSX-5000测试参数

直流环路电阻深度解释 – 福禄克DTX-1800和DSX-5000测试参数，深圳连讯达18年从事福禄克中国地区的产品销售和技术支持服务。而福禄克DTX-1800和DSX-5000是网络测试仪中的热卖产品。其中有一项测试参数是直流环路电阻。有许多客户对它有疑问，那么它是什么意思呢？

DC?Loop?Resistance?is?the?total?resistance?through?two?conductors?looped?at?one?end?of?the?link.?This?is?usually?a?function?of?the?conductor?diameter?and?varies?only?with?distance.?This?measurement?is?sometimes?done?to?ensure?there?are?no?gross?misconnections?which?can?add?significant?resistance?to?the?link.?Note?that?the?wire?map?test?automatically?isolates?breaks?but?not?high?resistance?connections.直流环路电阻是一条链路环在一起的总电阻。它通常是导线直径的函数，并且仅随距离。这种测量方法是有时做是为了确保没有漏掉可加显著电阻的链路。需要注意的是接线图测试自动隔离中断，但不高电阻连接。

DC?resistance?is?often?confused?with?impedance,?a?term?describing?the?dynamic?resistance?to?signal?flow,?usually?at?a?specified?frequency.?Both?are?measured?in?ohms?because?they?define?different?types?of?opposition?to?electrical?current?flow.?DC?resistance?increases?proportionately?with?the?length?of?the?cable?tested?while?impedance?remains?”fairly”?constant?regardless?of?length.直流环路电阻通常是与阻抗混淆，这个词描述动态电阻信号流，通常是在指定的频率。它们都是用欧姆因为他们定义不同类型的电流阻抗。随着长度的的增加直流电阻将会增大，但是特性阻抗是不随长度而变化的。

From?a?signal?perspective,?attenuation?(sometimes?called?insertion?loss)?is?now?a?more?useful?measurement,?and?DC?resistance?has?become?less?important.?Well,?not?quite?with?VoIP?becoming?popular?which?provides?power?over?the?cable.从信号的角度来看，衰减(有时称为插入损耗)现在是一个更有用的测量，并且直流电阻已变得不那么重要。而不是随着VoIP的流行而流行。
Results?Interpretation
Variations?in?loop?resistance?between?pairs?can?often?be?a?quick?indication?of?a?cabling?problem.?In?a?shorted?loopback?test?environment,?the?expected?value?is?simply?twice?the?sum?of?the?value?expected?for?the?given?length.?This?is?a?simple?test?for?any?advanced?field?tester.
结果解释：
线对之间的环路电阻变化，通常可以快速确定布线问题。在一个短链路环回测试的环境，结果是被给线路长度的两倍，对于与任何先进测试仪，这都只是一个简单的测试。

The?values?will?be?different?for?each?pair?combination,?due?to?the?different?twist?rates?between?the?pairs.?Looking?at?the?above?result,?we?could?conclude?that?the?1,2?pair?has?the?tightest?twist?and?7,8?has?the?least?twist.?This?is?normal?and?to?be?expected.每队线对的直流环路电阻的值是不一样的，因为线对见的绞距是不一样的。通过看以上结果，我们可以得出，1,2线对有比较密的绞距，7,8线对有比较松的绞距。
Troubleshooting?Recommendations
In?the?case?of?unexpected?high?DC?resistance,?compare?the?failed?pair?against?other?pairs?in?the?cable.?This?will?determine?whether?the?issue?is?specific?to?the?one?failed?pair?or?due?to?a?problem?affecting?the?entire?cable.?If?a?single?pair?is?at?fault,?inspect?termination?points?for?a?poorly?made?or?oxidized?connection.

故障排除建议
意想不到的高的直流电阻，通过比较失败的线路和其他线路。这将决定这个问题是否是由于特定于一对失败的问题影响整个电缆。如果只是一条链路错误，可以检测线路是否制作粗糙或者有氧化。