fluke DSX-5000中TCL与ELTCTL是什么意思？测试不过怎么办？

福禄克DSX-5000中国区代理深圳市连讯达电子技术开发有限公司福禄克网络部工程师为大家TCL与ELTCTL两个参数的意思。(PS:这是DTX-1800里面没有的参数）

transverse conversion loss  TCL 横向变换损耗
transverse conversion transfer loss  TCTL 横变换转移损耗
TCL (Transverse Conversion Loss) – DSX CableAnalyzer TCL is one of two balance measurements found in ANSI/TIA-568-C.2, ANSI/TIA-1005 and ISO/IEC 11801:2010. The other is ELTCTL.

The measurement is made by injecting a differential mode signal (DM) into a twisted pair, then measuring the common mode signal (CM) returned on that same twisted pair. The smaller the CM signal returned, the better the TCL measurement (balance).
 
翻译：测量是通过向双绞线注入差模信号（DM），然后测量同一对双绞线返回的共模信号（CM）。CM信号返回的越少，TCL参数就会越好，越平衡。

If it looks similar to a Return Loss measurement, you're right. Except a Return Loss measurement is made by injecting a DM signal into the pair and measuring the DM signal returned. Here we are measuring the CM signal returned which is TCL.

翻译：如果你觉得它像是回波损耗的测试，那你就说对了。回波损耗测试是通过向双绞线注入DM（差模信号）然后测试返回的DM信号，然而TCL是测试CM信号。

Field test requirements for ANSI/TIA-568-C.2 are deferred to ANSI/TIA-1152. At this time, TCL is not a field test requirement because until the DSX CableAnalyzer came along, no field test equipment vendor could perform a TCL field test. It is anticipated that other test equipment vendors will eventually offer TCL field measurements too. Field testers are normally capable of DM measurements only – the DSX CableAnalyzer is capable of both DM and CM measurements, hence its ability to measure TCL and ELTCTL.

翻译：对于ANSI/TIA-568-C.2现场测试要求直到ANSI/TIA-1152标准。在那个时候，TCL并不是一个现场测试的要求，因为没有现场测试设备供应商可以执行TCL现场测试，直到DSX-5000电缆认证分析仪的诞生。预计其他品牌测试设备厂家最终也将提供TCL现场测量。现场测试人员通常仅能DM测量 – 对DSX-5000电缆认证分析仪能够既DM和CM的测量，因此其有测量TCL与ELTCTL的能力。

If you wish to add TCL and ELTCTL to your standard Category 5e, 6, 6A or Class D, E or EA test, select your test limit under the folder in DSX called Balance Measurements and look for your test limit with a suffix of (+TCL):

翻译：如果需要对于Cat5e，Cat6，Cat 6A测试TCL和ELTCTL参数，你只需要再DSX-5000 的文件夹下面找到+TCL的后缀就可以了。

This will add ≈ 6.6 seconds to your AUTOTEST time.
TCL测试将增加6.6秒测试时间。
The suffix of (+TCL) indicates a standard ANSI/TIA or ISO/IEC test with the addition of TCL and ELTCTLmeasurements. ANSI/TIA-568-C.2 and ISO/IEC 11801:2010 only provide test limits for Channel measurements at this time. If you select a Perm. Link test limit, the TCL and ELTCTL measurements will be performed, but there will be no PASS/FAIL criteria applied. You will also see the Industrial Ethernet standards TIA 1005 with the different E1, E2 and E3 environmental TCL and ELTCTL limits.

翻译：有（+TCL）后缀的预示着ANSI/TIA或者ISO/IEC测试有这个规格。 目前ANSI/TIA-568-C.2 and ISO/IEC 11801:2010 仅仅提供信道测试的极限值，如果选择永久链路测试，TCL和ELTCTL也会被执行，但是不会有通过/失败的标准。同样你也会看到工业以太网标准TIA 1005 ，E1,E2,E3的标准的限制。
 
In the example below from a DSX-5000 CableAnalyzer, a Category 6A Channel was tested. With a margin of 5.4 dB (6 dB is a factor of 2), you can feel confident that this link will perform well, even in a noisy environment.
翻译：从下面DSX-5000的例子中可以看到，Cat 6A通道测试有5.4db的余量，你就不用担心了，因为这条链路表现非常好。即使在有噪音的环境下。