校园安防智能电话报警系统设计

基于现有公共电话网络，结合射频无线通信及传感器技术，设计开发一种用于校园安防的智能报警系统。系统在探测器端上加入编码发射电路，每个探测器编码由12位组成，编码信号包括探测器的位置信息和探测器类别信息。报警终端采用无线接收方式接收编码信号，用单片机软件译码取代专用集成电路芯片硬件译码，12位编码数据位中的位置信息编码位数和探测器种类编码位数可根据实际使用场合灵活定义，突破了采用集成芯片译码只有4～6位数据位的局限性。实验结果表明：探测器无线发送距离为200 m，在8位位置信息码，4位探测器种类信息码，每位两种状态的编码方式下，每个报警终端可接入探测器的数量达256个。

Abstract:

 A kind of intelligent alarm system for campus security is designed based on public telephone network. This system integrated the technologies of radio frequency wireless communications and sensors. Coded and emitter circuit was added in detectors， each detector’s coded was consisted of 12 bits， and detector-s coded signal included its position information and category information. Encoded signals were received by alarm terminal through wireless receiver， and software decoding method was used to replace the method of application specific integrated circuit decoding. The data bit of position information and category information could be defined according to applications flexibility， which breach limitation of only 4～6 data bits in the method of integrated circuit decoding. Experimental results show that detector-s wireless transmission distance can reached 200m， and the number of detectors which placed in one alarm terminal is up to 256， under the circumstances of 8 bits position code， 4 bits category code， and each bit included 2 states.