專注福祿克測試儀銷售與技術

Known issue in previous DTX code The “ISO ClassEa Ch AMD1 Low IL” and “ISO ClassEa PL2 25N1599?Lo IL” test options in the DTX had an insertion loss limit of 12 dB at 450 MHz to prevent the user from incorrectly applying the “12 dB rule” detailed previously. The DTX CableAnalyzer (Version 1.36 limits) had an insertion loss limit that has a step response at 450 MHz as indicated below:

This could result in a measurement incorrectly assigning a FAIL for the insertion loss parameter. It’s incorrect because the existing limit for insertion loss still applies; the 12 dB is only used for assessing whether the relaxed NEXT limit should be applied. As a result, we have changed the limit for insertion loss in the DTX CableAnalyzer and LinkWare software. The above result will now look like:

The change indicated was incorporated into the DTX CableAnalyzer Software Version 2.22 and LinkWare 6.0 releases. If the AUTOTEST fails now, it’s because it failed to meet the 12 dB insertion loss requirement at 450 MHz, indicating that this test option cannot be used to achieve a PASS result for the Class EA?channel. It is possible for the DTX CableAnalyzer to report a PASS* for insertion loss @ 450 MHz if the measured insertion loss at 450 MHz is closer to 12 dB than the specified accuracy of the DTX CableAnalyzer. This PASS* for insertion loss?indicates that the DTX CableAnalyzer cannot determine within its measurement accuracy whether the relaxed NEXT and PS NEXT limits are applicable. It does not necessarily indicate that the measured insertion loss is within the measurement uncertainty of the limits for insertion loss that is applicable to ISO/IEC 11801 Class EA?cabling. If necessary, the true insertion loss performance of the cabling can be verified using the regular “ISO11801 Channel Class Ea” and “ISO11801 PL2 ClassEa”?test options, and observing the test result for insertion loss. If this result does not contain a PASS* result for insertion loss, the PASS* for insertion loss of the ISO11801 Chan ClassEa?Low IL test, technically speaking, should be a PASS and not PASS*. This is a limitation of the code in the DTX CableAnalyzer. In conclusion: The overall result of an ISO/IEC 11801 Class EA?test should be as follows:

• If either the “ISO11801Channel Class Ea” or “ISO11801Chan Class Ea Low IL” test shows a pass, the result is a PASS.
• If either the?”ISO11801 PL2?ClassEa” or “ISO11801 PL2 ClassEa Low IL”?test shows a pass, the result is a PASS.
• If the “ISO11801Chan Class Ea Low IL” or “ISO11801 PL2 ClassEa Low IL”?test shows a PASS* that is caused by the result for insertion loss only, the result of the “ISO11801Chan Class Ea Low IL” or “ISO11801 PL2 ClassEa Low IL”?should be reviewed for insertion loss only; if this result is a PASS, the result of the “ISO11801Chan Class Ea Low IL” or “ISO11801 PL2 ClassEa Low IL” test can be considered to be PASS (the ‘*” is not applicable).