国产精品岛国久久久久-国产精品第-国产精品第13页-国产精品第1页在线观看-国产精品第44页-国产精品第5页

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

聯系我們

  • 全國統一服務熱線：

    134 1039 1245
    400-996-0787
    0755-8399 9818

  • 聯系郵箱：

    sales@faxytech.com

  • 聯系地址：

    深圳市福田區華強北路華聯發大廈602室

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

Aus/NZ

JIS


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.


1.png

2.png


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:


3.gif


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.


4.gif


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:


5.gif


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


6.gif


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:


7.gif


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:


8.gif


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:


9.gif


Looking at the Insertion Loss for Pair 4,5:


10.gif


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:


11.gif


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

相關配件（）
主站蜘蛛池模板： 国内视频一区二区| 色综合久久91| 伊伊综合| 亚洲欧美日本视频| 天堂精品在线| 欧洲午夜视频| 九九热线精品视频18| 国产乱码| 99热久久国产精品这里有99| 亚洲精品乱码久久久久久| 人人草人人干| 久久天天躁综合夜夜黑人鲁色| 九九99久麻豆精品视传媒| 国产露脸系列magnet| 综合网在线视频| 四虎国产永久在线精品免费观看| 免费看一级特黄a大片| 国产男女爱视频在线观看| 中文国产日韩欧美视频| 性夜黄a爽爽免费视频国产| 欧美亚洲国产一区| 狠狠的操你| 成人免费小视频| 在线人成精品免费视频| 亚色91| 欧美精品久久久久久久小说| 国产综合图区| 综合色网站| 色综合久久中文字幕综合网| 久久久欧美综合久久久久| 国产亚洲欧美一区| 最新日韩在线观看| 色婷婷色综合| 久久国产精品广西柳州门| 国产精品第九页| 一级特黄特交牲大片| 四虎影在永久地址在线观看| 两性视频久久| 国产99视频精品一区| 亚洲精品欧美精品| 欧美经典人人爽人人爽人人片|