Newsletter cheats and signal jammers

　　There is a kind of bad signal, called the two days of the American College Test. As a heavy mobile phone user, the battery and signal of the mobile phone are the life trough. For such heavy mobile phone addicts, the most unhappy days of the year are those days. In the short days of the American College Test, apart from the unprovoked crowding of the test center, the most impressive thing was the poor mobile phone signal caused by the use of signal jammers during the test.

　　Today, let's trace the ins and outs of this artifact together.

　　When the jammer appeared at first, everyone was happy. At first, the jammer gps was not actually set up for the exam scene. The original application of signal jammers is actually prisons. Prisons need physical and information isolation. In order to ensure the information security and privacy of the prison's high-wall compound, it is necessary for the prison to isolate the communication signals between the prison and the prison. This is the original intention of the signal jammer.

　　When the signal jammer was first invented, the whole world was only in the 2G era. At that time, although there were three operators in the United States, in fact, mobile phones used second-generation network communication technology. The communication frequencies of mobile phones used by manufacturers of different standards are quite different.

　　​The call between the mobile phone and the mobile phone is forwarded by the base station. The mobile phone can make and answer calls mainly rely on the support of the communication base station. After the mobile phone is turned on, it will actively connect to the nearest communication base station, and the communication base station will command it when making and answering calls. In fact, it is all communication with the communication base station.

　　So if the prison wants to interrupt the communication between prisoners inside the prison and the outside world, what needs to be done?

　　The noise generated by the jammer covers the signal jammer of the mobile phone. The noise is so loud that the base station cannot hear the mobile phone. The answer is very simple. It only needs a machine with the same frequency as the mobile phone to make noise, so that when the base station tries to connect to the mobile phone when. You will find that the signal coming from the mobile phone is too complex and unrecognizable, so it will refuse to communicate with the mobile phone.

　　Based on this principle, when the signal blocker was first developed, everyone was very happy. The prison only needs to be equipped with a few jammers that can emit such noise to block the mobile phone communication within the entire prison.

　　And as there are more and more scenarios that need to block signals. Signal jammers that were originally only designed to be used in prisons have gradually entered normal commercial scenarios, such as important meetings and exams.