To eliminate the phenomenon of fraud in the test, all laboratories now use cell phone cloaking devices that can block cell phone signals. Next, Shankino will introduce the operating principle of mobile phone shield equipment in the examination room, but what are the precautions when purchasing mobile phone shield equipment?
Operating principle of signal removal in the test room
Mobile jammers scan at a specific speed from the low-end frequency to the high-end of the forward channel during the work process. This scan speed can cause garbled interference in the message signal received by the mobile phone, and the mobile phone cannot detect normal data transmitted from the base station, so the mobile phone connects with the base station. Cannot be established. Mobile phones appear as a phenomenon of searching the network, no signal on the mobile phone, no service system, and so on. In mobile phone systems uplink and downlink channels, techniques such as frequency multiplication, frequency division, and frequency hopping filtering are used to analyze the required shield frequency and a spherical shield space depending on the power of the shield device. Customizes to automatically form a shielded magnetic field within the specified range. Disable mobile phones (NTT DoCoMo, Softbank, AU By KDDI, eMobile, WILLCOM) in this space. When the GPS jammer is in operation, it may disable the signal transmission / reception function of the mobile phone in the specified range and prevent dial-out and dial-in in order to achieve the purpose of the forced prohibition.