In the annual college entrance examination and entrance examination, major operators will issue a warm reminder: In order to ensure the smooth flow of signals around the campus, the operators have arranged in advance for communication engineers to test the entrances and exits of each test center and the rest area of the parents accompanying the test, and conduct tests on nearby base stations. Software and hardware expansion to ensure the communication needs of parents in the test area during the test. Except that the signal is blocked during the exam, we have done our best to ensure that your communication is smooth. Every year in the college entrance examination, in order to prevent exam fraud, all communication signals in the examination room will be shielded. There are cell phone jammer in the exam room. Common signal jammers: At the same time, there is a radio monitor outside the exam room that can help fix those frequency bands that the mobile phone jammer can’t take care of. Electromagnetic wave signals, real-time monitoring of radio wave signals from unknown sources.
The working principle of the signal jammer used in the college entrance examination is to obliterate the useful electromagnetic wave signal in a large number of useless signals. Under normal circumstances, when we use a mobile phone, the mobile phone is first connected to the carrier’s base station, and the radio wave signals sent by the two parties come and go. However, when the jammer is turned on, gongs and drums will be beaten around the mobile phone, sending out a noise radio wave signal that is many times larger than the received base station signal power. The mobile phone can’t hear what the base station is talking about and cannot receive the base station’s signals normally. The connection was severed. Whether calling, texting, or other various functions, they are all in a paralyzed state.
This is why the signal jammer affects the call and Internet access of mobile phone users around the examination room. The working principle of the jammer is as follows: in a certain frequency range, the mobile phone and the base station are connected by radio waves, and the data and sound transmission is completed with a certain baud rate and modulation method. Aiming at the above-mentioned communication principle, the jammer scans from the low end frequency of the forward channel to the high end at a certain speed during the working process. The scanning speed can cause garbled interference in the message signal received by the mobile phone, and the mobile phone cannot detect the normal data sent from the base station, so that the mobile phone cannot establish a connection with the base station. The mobile phone is manifested as a search network, no signal, no service system and other phenomena. Eventually, the mobile phone has no signal and cannot receive text messages or calls.
The current mobile phone signal jammer is full-band. It can shield all the 2G 3G 4G signals, 2.4G WIFI signals and Bluetooth signals under all the three operators of China Mobile, China Unicom and Telecom. Its principle is sent by itself. The frequency interferes with the mobile phone receiving the frequency from the base station and wireless router, so as to achieve the purpose of shielding them.