If successful, this work would be of
interest to the TIA TR-42.7 group. As much work as we have done on
assessing the effects of balance parameters on alien crosstalk
couplings, this remains a missing link.
Sterling
On 7/11/2012 9:27 AM, Müller, Thomas wrote:
Sterling
On 7/11/2012 9:27 AM, Müller, Thomas wrote:
Hi Sterling,I totally agree. The EMC behaviour is determined by the mode converion properties and the shielding attenuation of the cable. This defines the coupling attenuation for a differential signal. In the differential ethernet cable specs therefore there are different critieria for shielded cables (coupling attenuation > 60 dB, e.g. to be measured with a triaxial measuring setup or absorbing clamp) and mode conversion for unshielded cables. An unshielded cable somehow has to rely on its mode conversion attenuation only, whereas a shielded cable is by far less proune to the surrounding. The problem is that the automotive industry aims at using the cheapest possible solution, best unshielded and unjacketed. We are wondering to which extend this will be possible in the Gigabit range.We have planned to do some measurements in the EMC lab to get an impression, how mode conversion related to EMC emissions in order to fulfil the automotive limits.Best regardsThomas
Von: sterling [mailto:sterlingv@xxxxxxxxxxxxx]This is a complex question. The TCL and TCTL of a pair in a modern cable are largely determined by the other pairs in the cable. The properties of the cable pair are optimized for the proximity to the other pairs and to the cable jacket. If we remove a pair from the cable, for example, the characteristic impedance will change, as well as the propagation velocity, etc. So the pair must be designed from the beginning to work in free air. But the intended environment is not free air, it is a cable harness.
Gesendet: Mittwoch, 11. Juli 2012 15:13
An: Müller, Thomas
Betreff: Re: [802.3_RTPGE] AW: [802.3_RTPGE] Answers to PoE and Channel Model ad hoc
To minimize the effect of the cabling harness, the pair can be designed with a foil shield. It will then be largely unaffected by the environment, and can be measured for performance in free air as well. The TCL and TCTL, however may not be as high performance as an unshielded pair. The TCL and TCTL performance will be much less important, though, because the coupling coefficient between the pair and the outer world will be many times lower.
>From experience, I would say that it will be difficult to measure and enforce strict requirements on TCL and TCTL.
Sterling
Sterling Vaden
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sterling.vaden@xxxxxxxxxxxx
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On 7/11/2012 7:44 AM, Müller, Thomas wrote:
Thanks Thilo, this gives a good impression on the automotive cabling environment. For EMC considerations it would have been interesting to have a look at the mode conversion S-parameters of the channel as well (Sdc11 and Sdc21, TCL and TCTL) and best compare it with a cable not integrated in a wiring harness to see to which amount it degrades. Maybe this can help to define requirements for the cable. Best regards Thomas Thomas Müller Dipl.-Ing.(FH) Forschung & Entwicklung Rosenberger Hochfrequenztechnik GmbH & Co. KG Hauptstraße 1 - D-83413 Fridolfing Tel. +49 (0)8684 18-351 Fax: +49 (0)8684 18-197 www.rosenberger.de ________________________________ Von: Thilo Streichert [mailto:thilo.streichert@xxxxxxxxxxx] Gesendet: Montag, 9. Juli 2012 09:34 An: STDS-802-3-RTPGE@xxxxxxxxxxxxxxxxx Betreff: [802.3_RTPGE] Answers to PoE and Channel Model ad hoc Dear RTPGE-Colleagues, Stefan and I discussed the questions of the PoE and the Channel Model questionnaire. The answers and some figures of a wiring harness with typical automotive connectors can be found in the following PDF: Unfortunately, we cannot attend the San Diego meeting, but we can discuss upcoming questions of course by mail or phone. Kind regards, Thilo Dr. Thilo Streichert Daimler AG Group Research & Advanced Engineering E/E-Architectures & Standards HPC: G007/W59 - RD/ESA 71059 Sindelfingen/Germany Phone: +49 7031 4389845 Mobile: +49 151 5860 4771 Fax: +49 711 3052195843 Mail: Thilo.Streichert@xxxxxxxxxxx Address for visitors Room 3.043 Hanns-Klemm-Str. 45 D-71034 Böblingen Germany Daimler AG Sitz und Registergericht/Domicile and Court of Registry: Stuttgart HRB-Nr./Commercial Register No. 19360 Vorsitzender des Aufsichtsrats/Chairman of the Supervisory Board: Manfred Bischoff Vorstand/Board of Management: Dieter Zetsche (Vorsitzender/Chairman), Wolfgang Bernhard, Christine Hohmann-Dennhardt, Wilfried Porth, Andreas Renschler, Bodo Uebber, Thomas Weber If you are not the intended addressee, please inform us immediately that you have received this e-mail in error, and delete it. We thank you for your cooperation. Rosenberger Hochfrequenztechnik GmbH & Co. KG, Registergericht: Amtsgericht Traunstein, HRA 5566 persoenlich haftender Gesellschafter: Rosenberger Hochfrequenztechnik GmbH, Registergericht: Amtsgericht Traunstein, HRB 4405 Geschaeftsfuehrer: Dipl.-Kfm. Hans Rosenberger, Dipl.-Ing. Bernhard Rosenberger, Dipl.-Ing. Peter Rosenberger, Dr. rer. nat. Tosja Zywietz Disclaimer http://www.rosenberger.com/Disclaimer/disclaimer.html
Rosenberger Hochfrequenztechnik GmbH & Co. KG, Registergericht: Amtsgericht Traunstein, HRA 5566
persoenlich haftender Gesellschafter:
Rosenberger Hochfrequenztechnik GmbH, Registergericht: Amtsgericht Traunstein, HRB 4405
Geschaeftsfuehrer: Dipl.-Kfm. Hans Rosenberger, Dipl.-Ing. Bernhard Rosenberger, Dipl.-Ing. Peter Rosenberger, Dr. rer. nat. Tosja Zywietz
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