基于現(xiàn)有公共電話網(wǎng)絡(luò)，結(jié)合射頻無(wú)線通信及傳感器技術(shù)，設(shè)計(jì)開(kāi)發(fā)一種用于校園安防的智能報(bào)警系統(tǒng)。系統(tǒng)在探測(cè)器端上加入編碼發(fā)射電路，每個(gè)探測(cè)器編碼由12位組成，編碼信號(hào)包括探測(cè)器的位置信息和探測(cè)器類別信息。報(bào)警終端采用無(wú)線接收方式接收編碼信號(hào)，用單片機(jī)軟件譯碼取代專用集成電路芯片硬件譯碼，12位編碼數(shù)據(jù)位中的位置信息編碼位數(shù)和探測(cè)器種類編碼位數(shù)可根據(jù)實(shí)際使用場(chǎng)合靈活定義，突破了采用集成芯片譯碼只有4～6位數(shù)據(jù)位的局限性。實(shí)驗(yàn)結(jié)果表明：探測(cè)器無(wú)線發(fā)送距離為200 m，在8位位置信息碼，4位探測(cè)器種類信息碼，每位兩種狀態(tài)的編碼方式下，每個(gè)報(bào)警終端可接入探測(cè)器的數(shù)量達(dá)256個(gè)。

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.

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