The intrusiveness of mobile phones.
In essence, the shielding of mobile phone signals is the electromagnetic interference with the wireless network of mobile phone communication, so that the mobile phone cannot enter the network, receive information from the mobile network, and send information out through the network. However, this kind of signal has no effect on mobile phones. effect.
The interference principle of mobile phones is: within a certain frequency range, data and sound are transmitted between the mobile phone and the base station through radio waves with a certain baud rate and modulation method. According to the above communication principle, the cell phone jammer scans the low-end frequency to the high-end channel at a certain speed. Such a scanning speed will cause garbled interference in the information signal received by the mobile phone. The mobile phone cannot detect the normal data of the base station, making it impossible for the mobile phone to connect to the base station. There are phenomena such as network search, no signal, and no service system.
Which channel is the BCH, because any frequency band for mobile communications contains multiple channels, and each of them can be used as a BCH, it all depends on the channel distribution of the MSC throughout the area. Generally, in order to prevent crosstalk caused by channels with similar frequencies, the frequencies of channels in the same community should be significantly different. For example, after using channels 5 and 6, it is forbidden to use channels 4, 6, etc. Adjacent cells are not allowed to use the same channel and adjacent channels. Multiple channels are allocated in each cell, one of which is the BCH and the other is the service channel.
Because the shielding characteristics of mobile phone signals are not fixed, there may be two or more BCH interference in areas near the community. When using a signal jammer for sale, all channels that may appear in the mobile communication network should be interfered with, such as all frequency signals in GSM, DCS, PHS, CDMA, SCDMA, WCDMA, TDS-CDMA and other frequency bands, and all mobile phone signals should be interference. In short, it blocks the signal received by the mobile phone and cuts off the connection between the mobile phone and the base station.