The jammer transmits the signal of the same frequency as the mobile phone and the power is strong enough to allow the two signals to conflict and cancel each other. Since the mobile phone can automatically increase the power when it encounters slight interference, the jammer must be able to recognize the power increase of the mobile phone and increase its power accordingly.The mobile phone is a full-duplex device, which means that it uses two separate frequencies for speech and listening. Some jammers only block one frequency, but they also have the effect of blocking two frequencies at the same time. Since the mobile phone can only receive one frequency at this time, it will mistakenly believe that the mobile phone has no service.
Every year during the college entrance examination, the school will have network problems such as mobile phone disconnection and slow Internet speed. That is because the school has opened a cell phone jammer.If we think of a mobile phone as a handheld two-way radio, the radio can be interfered, and the mobile phone is no exception. Like any radio, the signal of a mobile phone will be interfered.Interfering with mobile phones is like interfering with any other type of radio communication. The mobile phone communicates with its service network through the base station.
When mobile phone users drive down the street, the signal is switched from one base station to another.We know that wireless communication uses electromagnetic waves for communication. The functional characteristics of electromagnetic waves are determined by their frequency.At present, the main principle of signal shielding and signal jamming is to emit huge noise in the frequency band used by mobile phones, which interferes with the reception and transmission of normal signals of mobile phones. This small object is not only often used to prevent cheating in exams, but also politically and militaryly to prevent terrorist attacks. However, signal jammers are not like shopping for food, they are not bought and used casually, otherwise they may be illegal.