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- 在7类铜线上可以以100Gps的速率传输100米的长度。这些铜线是由NEXANS公司提供，用于连接室内或建筑物内的电脑或用于并行计算系统的。
- 7类线比5类线采用了更重的双绞线，增加了屏蔽
- 采用了纠错和均衡技术
Researchers push transmission rate of copper cables
You may not be able to get blood out of a turnip, but according to PennState engineers, you can increase the data transmission of Category-7copper cables used to connect computers to each other and the Internet.
"Working with NEXANS, the company that manufactures the cable, we have examined the possibility of sending digital [size=100%]dataat a rate of 100 gigabits per second over 100 meters of Category-7copper cable," says Mohsen Kavehrad, the W.L. Weiss Endowed Chairprofessor of electrical engineering. "These are the current, newgeneration of Ethernet cables."
These cables are used to connect computers within a room or a building or to create parallel computing systems.
While the long distance lines of most Internet systems are glassfiber optic cables, which are very fast, copper cable is generally usedfor short distances.
"In home networks, for example, it is expensive to use fiber opticcabling," says Ali Enteshari, graduate student in electricalengineering who presented the team's methods to the IEEE High SpeedStudy Group today (Nov. 14) in Atlanta.
All transmission cables are limited by the distance they cantransmit data without degradation of the signal. Before errors andinterference make the signals non-recoverable, cable systems userepeaters – which are similar to computer modems – to capture, corrector [size=100%]recover data, and resend it. The distance between repeaters depends on the cable and the approach used by the modem to correct errors.
"What we are offering is a less expensive solution and one that iseasier to build," says Jarir Fadlullah, graduate student in electricalengineering.
Using information on specifications and characteristics of thecables from NEXANS, the researchers modeled the cable with all itsattributes including modeling crosstalk. They then designed atransmitter/receiver equipped with an interference canceller that couldtransfer up to 100 gigabits using error correcting and equalizingapproaches. Ethernet cable like the Category 7 is made up of four pairsof twisted wires shielded to reduce crosstalk. Category 7 is heavierweight wire with better shielding than Category 5 cable. Kavehrad'sgroup did similar analysis on the Category 5 cables in 2003.
"A rate of 100 gigabit over 70 meters is definitely possible, andwe are working on extending that to 100 meters, or about 328 feet,"says Enteshari. "However, the design of a 100 gigabit modem might notbe physically realizable at this time as it is technology limited. Weare providing a roadmap to design a high speed modem for 100 gigabits."
The researchers believe that two or three generations in thefuture, the technology of chip circuitry will allow these modem designsto be built. Currently, chip design is at about 65 nanometers, but theyexpect in the next two generations to get to what is required, saysKavehrad.
The amount of data encompassed by 100 gigabits is amazing. Theentire Encyclopedia Britannica contains 1 gigabyte of information. Abyte is equivalent to 8 bits, so 1 Gigabyte is equal to 8 gigabits. Arate of 100 gigabits per second over 100 meters is the transmission of12.5 Encyclopedia Britannica sets per second.
Source: Penn State |
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发表于 2007-11-15 16:30:52
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