The object of low heat resistance should keep away from cell phone jammer

The object of low heat resistance should keep away from cell phone jammer .
High-speed driving in the car. Tire failure was most worried about all the drivers and most difficult to prevent, but also the main reason for sudden traffic accidents. According to statistics, on the highway in the country, caused by the puncture accidents accounted for 70% of the total number of accidents; in the United States, this proportion is as high as 80%. Huge economic losses caused by a puncture, so while driving in the car, tire pressure changes on the real-time monitoring, automotive safety systems should be an essential function. Studies have shown that, to ensure that the standard tire pressure and tire to detect leaks is critical to prevent puncture. So tire pressure monitoring system TPMS (Tire Pressure Monitoring System) came into being. Direct and indirect TPMS are two kinds, the proposed direct-type TPMS. After more than a year, I successfully completed the TPMS system development, and after a large number of vehicle experiments, the results show that the development of the system is reliable, able to secure early warning purposes. And summarized below focuses on some key technical issues.In the mobile phone circuit, VCO circuit form from, there are separate components with the VCO circuit components. But the VCO circuit is also the basic component used in the VCO circuit with discrete components is similar. Compared to mining, said Motorola often the VCO circuit using discrete components, while other more use of mobile phones the VCO components. Either discrete components or VCO components, usually a three-capacitor oscillator circuit. Power supply adapter should be away from main machinery of cell phone jammer .
The more important in the phase-locked loop VCO is phase locked loop frequency synthesizer and the core circuit. It should meet some of the features this: output amplitude stability is better, the VCO operates in frequency band should meet this requirement, otherwise it will affect the phase sensitivity; frequency coverage to meet the requirements and there is margin; voltage-frequency characteristics of the linear transformation wide in scope. VCO phase detector output signal is compared with the reference signal. In the frequency synthesis, in order to improve control accuracy, the phase detector working at low frequencies. The VCO output frequency is relatively high, in order to improve the control accuracy of the loop, you can not do without frequency technology. cell phone jammer only shield the cell phone in the examination room and will not influence the cell phone outside the examination room.
When the VCO is in normal working condition, VCO output a fixed frequency. If some external factors such as voltage, temperature can cause the VCO frequency is increased, the frequency output signal is f2 / N n higher than the reference signal, the phase detector to detect the changes, the output voltage decreases, the varactor both ends of the reverse bias decreases. This makes the varactor diode junction capacitance increases, changes in the oscillation circuit, VCO output frequency is reduced.