Usb 3.0 interfaces are popular functions on USB Hub. With it, you can directly put the required 2.4G Wireless Mouse or Keyboard in the Hub. But sometimes, you will find the 2.4G Wireless Mouse or Keyboard’s connection is not stable. What is going on? ?
It turns out that this is a normal phenomenon, and the official usb3.0 document also explains the reason for this situation: Why is there interference?
Any wired signal will radiate electromagnetic waves, unless it is direct current (no frequency change) or completely shielded. The intensity of the interference is related to the signal (such as voltage, current, frequency) transmitted on the cable. To give a particularly realistic example: generally under high-voltage lines, if you want to transmit Ethernet signals, the most reliable method is to use optical fibers. If you use twisted-pair copper cables to transmit signals, it is likely to be interfered. When designing most electronic devices, electromagnetic shielding and anti-interference issues must be considered.
Therefore, although USB3.0 is a wired signal, it may still radiate electromagnetic waves and interfere with other signals. So someone will ask, isn’t USB3.0 5GHz? How can there be interference when 2.4G wireless Mouse or keyboard is 2.4GHz? The problem lies in the USB transmission line. The transmission frequency of USB3.0 is indeed 5GHz serial, but USB3.0 uses 4 data lines to form 2 groups, each group is responsible for one transmission direction, realizing full-duplex two-way 5GHz, and the reference frequency of each data line is 2.5GHz . So, the total bandwidth is 5GHz, but each line is 2.5GHz. This frequency is too close to the 2.4G wireless frequency, and because most high-frequency equipment uses SSC technology (spread spectrum clock?) to make the signal It is not completely distributed on a fixed frequency, so it spreads to other frequencies around 2.5GHz, so it causes greater interference to 2.4G Wireless and Bluetooth.
So that’s why 2.4G wireless devices are easily interference by USB 3.0.