The mobile phone signal jammer actually implements electromagnetic interference to the wireless network on which mobile phone communication depends, making the mobile phone unable to access the network, and thus unable to receive information from the mobile network, and unable to send information through the network, but It has no effect on the signal generated by the mobile phone.
The principle of mobile phone (radio communication) is as follows: within a certain frequency range, the mobile phone and the base station are connected by radio waves, and the transmission of data and sound is completed with a certain baud rate and modulation method.
In view of the above-mentioned communication principle, the signal 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.
Because there are many channels in any frequency band of mobile communication, and each channel can be used as BCH, as to which channel in a cell is used as: BCH, it is determined by MSC based on the distribution of channels in the entire network area. . Generally, in order to prevent crosstalk between channels due to similar frequencies, there should be a large difference in frequency between channels in a unified cell. For example, after using channel 5, do not use channels 4, 6, etc., adjacent to each other. The same channel and adjacent channels cannot be used in a small area. Among the several channels allocated in each cell, one of the channels is designated as BCH, and the other channels are traffic channels. Because of the instability of the BCH, the uncertainty of the use of the jammer, and there may be two or more BCHs in the adjacent area of the cell, when the signal jammer is used to interfere, it should be possible to use the jammer in the area. All the channels of the mobile communication network started to interfere, that is, all frequency signals in the GSM, DCS, PHS, CDMA, SCDMA, WCDMA, TDS-CDMA frequency bands should be transmitted, so as to achieve interference to all mobile phone signals. It realizes the shielding of the signal received by the mobile phone, blocking the connection between the mobile phone and the base station.