The mobile phone signal jammer has become the standard equipment in the exam room. Not only the high school and college entrance examinations, but also the postgraduate exams, civil service exams and various qualification certificate exams, mobile phone signal jammers are needed to prevent candidates from communicating with the outside world through wireless signals. The current mobile phone signal jammers are all 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 to send out 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.
The principle of the cell phone jammer: within a certain frequency range, the mobile phone and the base station are connected by wireless electromagnetic waves, and the data and sound transmission is completed with a certain baud rate and modulation method. The communication principle of the mobile phone signal jammer, the jammer scans from the low end frequency of the forward channel to the high end at a certain speed during the working process. This 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. Now that we know that the communication method of wireless communication is to communicate using electromagnetic waves. The functional characteristics of electromagnetic waves are determined by their frequency.