直流環路電阻深度解釋 – 福祿克DTX-1800和DSX-5000測試參數

直流環路電阻深度解釋 – 福祿克DTX-1800和DSX-5000測試參數，深圳連訊達18年從事福祿克中國地區的產品銷售和技術支持服務。而福祿克DTX-1800和DSX-5000是網絡測試儀中的熱賣產品。其中有一項測試參數是直流環路電阻。有許多客戶對它有疑問，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.直流環路電阻是一條鏈路環在一起的總電阻。它通常是導線直徑的函數，并且僅隨距離。這種測量方法是有時做是為了確保沒有漏掉可加顯著電阻的鏈路。需要注意的是接線圖測試自動隔離中斷，但不高電阻連接。

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.直流環路電阻通常是與阻抗混淆，這個詞描述動態電阻信號流，通常是在指定的頻率。它們都是用歐姆因為他們定義不同類型的電流阻抗。隨著長度的的增加直流電阻將會增大，但是特性阻抗是不隨長度而變化的。

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.從信號的角度來看，衰減(有時稱為插入損耗)現在是一個更有用的測量，并且直流電阻已變得不那么重要。而不是隨著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.
結果解釋：
線對之間的環路電阻變化，通常可以快速確定布線問題。在一個短鏈路環回測試的環境，結果是被給線路長度的兩倍，對于與任何先進測試儀，這都只是一個簡單的測試。

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.每隊線對的直流環路電阻的值是不一樣的，因為線對見的絞距是不一樣的。通過看以上結果，我們可以得出，1,2線對有比較密的絞距，7,8線對有比較松的絞距。
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.

故障排除建議
意想不到的高的直流電阻，通過比較失敗的線路和其他線路。這將決定這個問題是否是由于特定于一對失敗的問題影響整個電纜。如果只是一條鏈路錯誤，可以檢測線路是否制作粗糙或者有氧化。