During the annual college entrance examination, residents around the school will respond to one question, that is, why the phone calls are always dropped, the Internet is slow, and text messages are sent out. In fact, the school turns on the digital signal jammer during the exam period, so the problem is I got rid of the problem of poor mobile phone signal when walking around the school. If we compare a mobile phone to a dual-speaker radio, then the radio waves will be interfered with, and the mobile phone will also be interfered with by the radio waves. Therefore, digital signal jammers use this to solve cheating in the exam room.
How digital signal jammers work
Making the mobile phone have no signal and unable to send text messages is actually the same as interfering with ordinary wireless communications. The mobile phone sends a specific signal, and then the base station receives the signal before the mobile phone can use the network communication. When going to different places, the base station will keep switching, just like a car passing by many places.
Everyone knows that mobile phone communications receive electromagnetic waves emitted by base stations for communication. The function of an electromagnetic wave is determined by its frequency. At this time, the mobile phone will display the 2/3/4G/5G networks of the three major operators. The mobile phone needs to emit certain radio waves in order to link to the operator's base station. Different operators use different frequencies, so that they will not collude with each other to cause errors. At this time, we can use a digital signal jammer to transmit an interference signal source based on the operator's base station-specific signal. Since the frequency is the same, it is not clear on the mobile phone which signal is the official base station signal, and then the "influence" is completed. As long as the station attempts to connect to the mobile phone, it only needs a computer with the same frequency as the mobile phone to emit "noise" with a huge output power. You will find the signal from the mobile terminal ugly and indistinguishable, so you will refuse communication with your smartphone. Early jammers only blocked one group of frequencies, such as 2G, while complex jammers for cell phone could block several types of Internet at the same time, such as 2/3/4G.