1. <pre id="lx0ul"><nobr id="lx0ul"></nobr></pre>

        1. <strike id="lx0ul"></strike>
        2. <object id="lx0ul"></object>

          <big id="lx0ul"><nobr id="lx0ul"></nobr></big>

          洞察行業資訊 分享專業知識

          洞察行業資訊 分享專業知識

          洞察行業資訊 分享專業知識

          洞察行業資訊 分享專業知識


          • 全國統一服務熱線:

            134 1039 1245
            0755-8399 9818

          • 聯系郵箱:

            [email protected]

          • 聯系地址:


          4db原則(法則)-英文原文 -福祿克DSX2-8000/DTX-1800

          A YouTube video explaining how this this works is also?available from here.

          This is applicable to the following cabling standards only:

          ISO/IEC 11801

          EN 50173



          When?the Insertion Loss is less than 4.0 dB at the frequency point where the measurement is made, then the measurement is ignored and not uated against the selected Test Limit/Cabling Standard in the DTX CableAnalyzer. This is often referred to as the 4 dB rule. It is not applied in the North American TIA Cabling Standards. Only certain test parameters and configurations will have the 4 dB rule. The tables below indicate which link? definitions and test parameters have the 4 dB rule applied to them. As an aid, the other rules are also listed.



          On a?short link, the Insertion Loss may never reach 4.0 dB. If that were to happen, then the entire measurement would be?ignored, or as the cabling standards phrase it; “recorded for information only”. If this were to happen with your DTX CableAnalyzer, you would see an “i” appear next to the summary result for that test parameter. In LinkWare software, the result would be recorded with “N/A’. An example is shown below:


          Concern is normally caused when the result has a negative margin. In this example we see the NEXT margin was -9.7 dB. A?negative margin is normally associated with a FAIL, but because the entire link never exceeded 4.0 dB Insertion Loss, it’s not a FAIL. Further?confusion lies in that the North American ANSI/TIA/-568-C.0 cabling standard does not have this 4 dB rule. If you were to test the same link above?with the same DTX CableAnalyzer, but using the North American Standard TIA Cat 5e Perm. Link, your result would be a FAIL.


          Please make sure you?have agreed in a Test Limit, in writing, before the project starts.

          Let’s review in detail how this works by looking at another example test result on the DTX CableAnalyzer.

          An ISO11801 PL Max Class D AUTOTEST was run on a short 6.0 m installed link, giving the following result:


          Looks normal. Let’s take a look at the NEXT result in a little more detail:


          You will observe that?the limit line has two colors, black and red. The cabling standards do not require the cable tester manufacturer to display where the 4 dB rule is implemented to the user, only that it is implemented. However, the DTX CableAnalyzer will indicate where the 4 dB rule has been implemented by changing the color of the limit line. If the?limit line is black,?the Insertion Loss was less than 4.0 dB. If?the limit line is red,?the Insertion Loss was 4.0 dB or greater. So for this Pair 1,2-4,5 the NEXT is not uated below 84.8 MHz. Let’s take a quick look at the Insertion Loss for Pair 4,5:


          As you can see, the Insertion Loss reached 4.0 dB at 84.8 MHz, as previously indicated in the NEXT Pair 1,2-4,5 graph above. NEXT contains two pairs. So which Insertion Loss pair do we use to implement the 4 dB rule? The disturbed pair is used for uation purposes. So if the worst case NEXT Pair was 1,2-7,8 then the?DTX CableAnalyzer would use the Insertion Loss values from Pair 7,8 to determine where the 4 dB rule is implemented.

          As previously mentioned, if the link is particularly short, then the Insertion Loss may never reach 4.0 dB and the entire NEXT result is “ignored”. Let’s take a closer look at the first example where the test result was:


          Looking at the worst case NEXT result, we see the entire limit line is black, suggesting that the Insertion Loss for Pair 4,5 never reached 4.0 dB:


          Looking at the Insertion Loss for Pair 4,5:


          We see that the Insertion did indeed never reach 4.0 dB, so the entire measurement is not uated against the limit line (ignored) and recorded as “i” Information Only. If this result was downloaded to LinkWare Software, the report would show N/A against this measurement:


          No further action is required by the installer. This is a valid standards compliant result.

          久久久av久av久片一区二区_亚洲成高清三区二区二区中文_成片人免费观看一级A片_国产日韓无码一区二区三区久久区 亚洲精品无码不卡在线观看 亚洲国产成人精品福利 久久99热精品免费观看 青草久久人人97超碰 高清免费a级在线观看 免费三级现频在线观看视频 国产精品欧美亚洲韩国日本久久 国产美女裸体视频全免费 国产成人午夜福利在线观看

          1. <pre id="lx0ul"><nobr id="lx0ul"></nobr></pre>

              1. <strike id="lx0ul"></strike>
              2. <object id="lx0ul"></object>

                <big id="lx0ul"><nobr id="lx0ul"></nobr></big>