针对通信电缆经常被盗割的现象,利用通信电缆任意两根芯线作为检测回路,按照一定距离并联滤波电阻器.当通信电缆被盗割后,检测回路的总电阻的变化会引起电流的变化,然后将电流变化量转化为电压变化量,再通过单片机的A/D转换后与事先设置好的报警数据比较,通过声光报警,提醒值班人员.设计给出了通信电缆防盗报警系统总体设计框图、整体电路设计、元件参数选择及系统程序设计.本设计产品通过应用到工程中实验,发现和预防了电缆被盗割.%In view of the situation that communication cables usually are stolen, it uses random two core wires of the communication cables as the detective circuit, filter resistances are paralleling according to some distance. When communication cables are cut, the total resistance of detective circuit courses the change of current, then the current variation turns into the voltage variation, after being converted by the A/D function of MCU, it's compared with the alert data which has been setting in advance, generating sound and light warning noticing the watchkeeper. This design shows the entire design block diagram, whole circuit design, choosing of component parameters and system program design of the communication cable security alarm system. The product of this design has been applied to engineering experiment, and it finds and prevents of the cable is stolen.
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