With the various problems brought about by the development of mobile phones, the spread and application of mobile phone signal jammers have also caused a lot of controversy in recent years. In the past college entrance examinations in June of this year, many schools installed such devices in their classrooms to prevent candidates from cheating, which indeed played a positive role.
Last year, a member of the CPPCC in the education sector in Guangzhou proposed that the government should fund the installation of mobile phone signal jammer in student dormitories to prevent students from chatting with mobile phone text messages and surfing the Internet after the lights were turned off at night, which would affect the next day's study. In response to this proposal, I also made an online query, and the results showed that the support or opposition rate did not exceed 50%-38% of the voting support devices were used to facilitate students’ rest, and 43% of the votes thought it was unnecessary, "Students should be self-disciplined." ", and another 18% of the votes support "the ability to set the cell phone area."
A certain library in Wuhan also set up a cell phone signal blocker in the reading room in a desperate situation. After a period of time, there have been countless disputes. Some readers think that they finally have a quiet reading environment, while some readers think that the library has been involved in the freedom of communication and will make mistakes at critical moments.
In fact, mobile phone signal jammers are not a new thing in foreign countries, and they have begun to be sold on the Chinese market in the past two years. Some radio enthusiasts have even developed a set of design drawings and published them on the Internet. The principle is actually very simple. To put it simply, it is like "speaking loudly than talking softly."
Regarding the operating principle of this kind of equipment, there is such a professional description: "The operating principle of a mobile phone is that within a certain frequency scale, the mobile phone and the base station are connected by radio waves, and the data and sound transmission is completed with a certain baud rate and modulation method. For this communication principle, the mobile phone jammer scans from the low-end frequency of the forward channel to the high-end at a certain speed. This scanning speed can form garbled interference in the message signal received by the mobile phone, so the mobile phone cannot detect the announcement from the base station With normal data, no connection can be established with the base station."
Because it only disturbs the downlink signal, this kind of equipment will not affect the mobile base station, nor will it affect the normal operation of other electronic equipment. Therefore, in the propaganda of the business, this equipment is called: "The use of foreign advanced technology is mainly for small places at home and abroad that require safety and confidentiality, such as private bosses, confidential offices, negotiation rooms, event vehicles, mobile Political and business dignitaries guard the scene, etc., and successfully developed high-tech products based on the actual conditions of mobile communications at home and abroad...giving you a piece of safety and giving you a piece of peace."
What is the function of this kind of mobile phone signal jammer? For example, you can buy a portable cell phone signal jammer with the smallest coverage. The cell phone signal jammer is similar in size to a general candy bar cell phone on the market, only about twice the thickness of a cell phone. The all-metal shell, with 3 antennas on the top, can disturb the signals of China Mobile, China Unicom, PHS, and even the recent 3G mobile phones. The instrument claims to be able to shield various cell phone signals within a radius of two meters.