1. Overview
Cell phone signal jammers are also called cell phone signal blockers, cell phone signal jammers, conference security devices, etc. communicate normally, thus achieving the goal of interference. The abuse of mobile phone jammers led to an increase in complaints of public communication interference, and the social response was strong and the normal communication order was greatly affected. In order to strengthen the use and management of the shielding device, we have explored its operating principle and management methods.
2. The working principle of cell phone jammer
Portable GPS jammers typically consist of a power supply, an electronic scanning control unit, a segmented radio frequency module module, an amplifier, a transmitting antenna, and other parts. Its working principle is usually generated by the sawtooth wave signal generator and the sweep signal is inverted by the inverter, then enters the voltage controlled oscillator to modulate the working frequency band of the mobile communication, then is amplified by the power amplifier and the tube voltage regulator controls the power. Frequency signals are transmitted through the air in the form of radio waves.
The working principle of mobile communication is that within a certain frequency range, the mobile phone and the base station communicate by radio waves, and complete the transmission of data and sound with a certain transmission speed and a certain method of modulation. The mobile phone communicates with the base station through the uplink frequency, then transfers the signal to the mobile service switching center MSC to complete the call. In the standby state, the mobile phone communicates with the base station via the BCH broadcast control channel. Once there is a call request, first ask the MSC through the BCH. The MSC assigns the mobile phone service channel according to the state of the channel in the cell, so that the mobile phone jumps from the BCH to the service. Make conversation on the channel. The mobile phone signal jammer sweeps from the frequency from the lower end of the front channel to the upper end at a certain speed during the working process according to the above principle. This scanning speed may cause scrambled 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 the mobile phone cannot establish a connection. with the base station.
3. Analysis of the current state and interference of mobile phone jammers
Today, there are many types of jammers available on the market, with different transmit power, interference frequency bands and coverage. In particular, some "three-nos" products are rough in workmanship, have poor emission indicators, RF units are not controlled in sections, and uplink and downlink frequencies interfere.