Nowadays, with the development of science and technology, more and more people use mobile phones to cheat. Every time they take an exam, there will be some people who practice favoritism and fraud. This has become an increasingly important issue for the education sector. In order to ensure the safety of examination information, some ordinary colleges and universities usually use signal jammers to interfere with external signals within a certain range. How does it interfere with mobile phone signals.

Signal jammer refers to a shielding device specially designed for signals near the examination room. Its working principle is to implement the same frequency signal interference to the wireless network used by communication equipment, so that it can not be connected to the network normally, so as to achieve the purpose of interference. The shield only shields the mobile phone signal, and has no impact on other electronic devices. It should be noted that in order to realize the shielding device to interfere with the mobile network, it must be ensured that the signal field strength sent by the shielding device is far greater than the field strength of the mobile signal BCH in the interference area. The closer the interference location is to the base station, the stronger the BCH field strength is, and the smaller the effective interference area is.
When using a mobile phone to make a call, you use the communication signal to contact the base station. The jammer is equivalent to releasing a piece of interference magnetic field, making the cell phone in this area disconnected from the base station and unable to talk. The signal sent by the mobile phone is submerged in the interference magnetic field, so as to achieve the goal of no signal.