Thunderbolt 3 Data Line Not Exceed 0.5 Meters
Why Thunderbolt 3 data lines generally do not exceed 0.5 meters?
In daily life, we come into contact with various cables, such as video cables, audio cables, network cables, and power cables. It is difficult for ordinary people to distinguish them without looking at the connectors. The intuitive difference in the hand is that some are thick, some are thin, some are hard, and some are soft.
Thickness and thinness are easier to understand. For example, if high-power power transmission is required, the wires will be much thicker, and more sets of data need to be transmitted, such as USB 2.0 and USB 3.0. The number of data lines will also be larger and the wires will be thicker.
Why are some threads of the same thickness so hard while others are soft? This has a lot to do with the internal structure of the wire.
The signal lines on the market can be divided into coaxial lines and twisted pair lines.
As the name implies, the coaxial cable is composed of a layer of insulating layer wrapped around the central copper conductor, and a metal mesh layer wrapped outside the insulating layer. Since the outer metal mesh and the central axis are on the same axis, it is called coaxial cable. axis
Why is the Thunderbolt 3 data cable generally no longer than 0.5 meters?
The opposite of the coaxial line is the twisted pair, that is, two wires with an insulating protective layer are intertwined with each other according to a certain helicity.
Why is the Thunderbolt 3 data cable generally no longer than 0.5 meters?
The signal line is composed of 6 sets of twisted pairs
What is the difference between these two lines?
Part of the interference of the data line comes from the external magnetic field, and the other part comes from the magnetic field generated by itself when transmitting the changing signal.
Due to the existence of the metal shielding network of the coaxial cable, the external magnetic field cannot pass through the shielding layer, and the internal magnetic field cannot pass through the shielding layer. When the signal is transmitted in the coaxial cable, the attenuation it receives is related to the transmission distance and the frequency of the signal itself.
For high-frequency signals, the longer the transmission distance, the greater the signal attenuation. In order to achieve the purpose of long-distance transmission of high-frequency signals, a coaxial amplifier is usually used to amplify and compensate for the signal.
Intel's Thunderbolt 3 data cable uses a coaxial cable. Due to the high-frequency attenuation of the coaxial cable, for a Thunderbolt 3 cable with a length of 0.5m, only a passive chip is required, and when it exceeds 0.5m, an active chip is required. The signal is amplified, and the price difference between the active chip and the passive chip is several times, so the Thunderbolt 3 line generally does not exceed 0.5m.
CHOETECH's 2m Thunderbolt 3 data cable uses active chips, and the price is five to six hundred RMB.
Why is the Thunderbolt 3 data cable generally no longer than 0.5 meters?
Twisted-pair wires lack metal shielding layers and are intertwined with each other. The interference signals generated by internal and external electromagnetic fields will cancel each other out partly, so it has the advantage of the strong anti-interference ability.
If it is required to have a strong anti-interference ability, shielded twisted-pair cables must be used. Our common Category 6e network cable is an unshielded twisted pair, and Category 7 cable is a shielded twisted pair.
In addition, twisted pair cables have many advantages such as long transmission distance, easy wiring, and low price. Of course, the feel is not like the axis.
