Every year during the high school exams, the school will present cell phone calls around the drop, slow Internet access and other network problems, that is because the school opened the wifi jammer. If we look at the phone as a handheld two-way radio, the radio can be jammed, the phone is naturally no exception. Just like any radio, the signal of a cell phone can be jammed.
The principle of wifi signal jammer is: in a certain frequency range, cell phones and base stations are linked up through radio waves to complete the transmission of data and sound at a certain baud rate and modulation. For the above communication principle, the jammer works at a certain speed in the process of scanning from the low end of the forward channel frequency to the high end.
The scanning speed can constitute a garbled interference in the cell phone admission message signal, the phone can not detect the normal data sent from the base station, so that the phone can not establish a connection with the base station. The cell phone performance for the search network, no signal, no service system and other phenomena. Eventually incur the cell phone no signal, can not receive SMS, phone.
Wireless communication is the application of electromagnetic waves to stop communication. The function of electromagnetic wave characteristics, is determined by its frequency. Our cell phone must be emitted to meet the requirements of electromagnetic waves, in order to connect to our communication operators base station. The fundamental principle of wifi jammer device is to transmit the same radio frequency as the cell phone, due to the same frequency, the cell phone can not distinguish which signal is the right base station signal, so as to complete the "interference". So this multi-network interference, and how is it done? It's actually quite simple. It is to cycle the way, repeatedly play three signals corresponding to the interference band, a one-time cover three bands, and this cycle of the distance is very small, so that the phone basically no time to speak only obediently sit down.
Signal shielding and wifi signal jammer, the main principle is currently in the cell phone use of the frequency band, issued a grand noise, disrupting the normal reception and transmission of cell phone signals. This small object, not only to avoid cheating during the examination, political and military are often used to avoid fear of attack.