Why are cell phone jammers a must-have during school exams?
When communication technology was still in the 3G era, mobile signal jammer could play a perfect role, because at that time, the frequency bands used by most operators were relatively fixed, and the bandwidth was relatively narrow, so interference would be relatively easy. However, with the rapid development of communication technology and the development of 5G and 4G communication technology, the signal jammer is faced with a dilemma. The signal interference originally designed only for 3G cannot cover the 3G and 4G signals due to the frequency, resulting in the failure of the shielding.
Fortunately, the signal blocker is also constantly developing and improving, and soon there will be an interference function specifically for the 5G and 4G frequency bands, which can block these three frequency bands at the same time and space.
Today's communication technology adopts advanced anti-interference technology, such as frequency hopping, direct sequence spread spectrum (DSSS) and other technologies, but the suppression of interference by frequency hopping and spread spectrum mainly relies on intermediate frequency filtering, because the front-end high-frequency amplifier and mixing frequency The devices are all nonlinear devices, and when accompanied by strong interference, there will be intermodulation interference and noise deterioration, that is, the blocking of the radio frequency front end.
In addition, there are many technologies for communication interference, such as broadband noise interference, noise interference in some frequency bands, multi-tone interference, frequency sweep interference, tracking interference, and smart interference. The cell phone signal jammer only needs to ensure that the communication signal is shielded within a certain small range, so generally as long as the frequency band can be covered, it is easier to interfere.
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