Breaking News
Comments
Newest First | Oldest First | Threaded View
RonCates
User Rank
Rookie
re: 10Gb/s Ethernet and 10GBase-T for the data center
RonCates   7/27/2011 11:37:27 PM
NO RATINGS
Sanjib – Yes, radiated emissions also need to be contemplated. But the good news is that the IEEE Standards body anticipated the potential for radiated emissions and has taken corrective measures. First, recognize that, like in 1000Base-T, 10GBase-T signaling is differential in nature and transmitted on twisted pairs that cancel emissions to first order. Nevertheless, there is residual radiation and even some common mode components due to non-idealities. To cope with those, IEEE was careful to architect the output energy of a 10GBase-T transmitter to be more evenly distributed over the transmission band and, furthermore, in Clause 55.9.5, requires compliant equipment to meet FCC Part 15 or CISPR 22 (depending on geography) limitations for radiated emissions. Bottom line: it’s purpose built to live and work in a data center environment without causing problems.

DF0
User Rank
Rookie
re: 10Gb/s Ethernet and 10GBase-T for the data center
DF0   7/27/2011 4:58:22 PM
NO RATINGS
I thought there was also an option for shielded cable for 10GBase-T.

Sanjib.A
User Rank
CEO
re: 10Gb/s Ethernet and 10GBase-T for the data center
Sanjib.A   7/26/2011 5:20:17 PM
NO RATINGS
Good point! I am not much concerned with only one cable. But I think, usually there would be many...isn't it? I thought it would be challenging to meet EMC norms as they would emit more when the cables are unshielded? But again I saw many have passed the EMC tests. One such example could be found below: http://docs.commscope.com/Public/Cat6AUTP_Passes_EMC_Tests.pdf

chanj0
User Rank
CEO
re: 10Gb/s Ethernet and 10GBase-T for the data center
chanj0   7/26/2011 3:18:58 PM
NO RATINGS
What is the current running through the cable that EMI becomes a concern?

Sanjib.A
User Rank
CEO
re: 10Gb/s Ethernet and 10GBase-T for the data center
Sanjib.A   7/26/2011 2:37:18 AM
NO RATINGS
Hi Ron, I got your points on crosstalk & EMC. Yes, that's how it could be done. Thanks a lot! Regarding the EMC (or rather EMI?) I was more concerned with the "unshielded cable" emitting RF energy creating trouble for others. Any thoughts?

RonCates
User Rank
Rookie
re: 10Gb/s Ethernet and 10GBase-T for the data center
RonCates   7/26/2011 1:26:38 AM
NO RATINGS
Sanjib – The Cat6A cables I have seen reduce alien crosstalk due to plastic ribs in their core which specially separate the twisted pairs. Since electromagnetic radiation intensity falls off as the square of the emission radius, it’s a very effective technique. As for Electromagnetic interference, I would agree with you if it wasn’t for the recent advances in the DSP algorithms inside of the 10GBase-T transceivers which have been shown to provide immunity to very strong EMI events of up to 10V/m. Those DSP engines are able to place a notch filter at the interferer’s emission frequency and prevent it from causing havoc with the received data.

Sanjib.A
User Rank
CEO
re: 10Gb/s Ethernet and 10GBase-T for the data center
Sanjib.A   7/25/2011 4:18:37 PM
NO RATINGS
As I know, the "alien crosstalk" was one of the biggest challenges for using the Cat6 cable for Gbit Ethernet. What is the change that is made in the insulation to reduce the alien crosstalk? In the second para in this article, it is mentioned about using "unshielded cable" for 10GbaseT. Again, I still see a major risk in using an unshielded cable for 10Gbit/sec due to EMC concerns.



EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Max Maxfield

Steve Wozniak Reacts to Latest iPhone
Max Maxfield
7 comments
Funnily enough, just a few days ago as I pen these words, I was chatting with my wife (Gina the Gorgeous) when she informed me that -- as a kid -- she had never played at making a ...

EDN Staff

11 Summer Vacation Spots for Engineers
EDN Staff
20 comments
This collection of places from technology history, museums, and modern marvels is a roadmap for an engineering adventure that will take you around the world. Here are just a few spots ...

Glen Chenier

Engineers Solve Analog/Digital Problem, Invent Creative Expletives
Glen Chenier
15 comments
- An analog engineer and a digital engineer join forces, use their respective skills, and pull a few bunnies out of a hat to troubleshoot a system with which they are completely ...

Larry Desjardin

Engineers Should Study Finance: 5 Reasons Why
Larry Desjardin
46 comments
I'm a big proponent of engineers learning financial basics. Why? Because engineers are making decisions all the time, in multiple ways. Having a good financial understanding guides these ...

Flash Poll
Top Comments of the Week
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)