超声波防盗报警器

介绍了利用超声波敏感器件作为发射头与接受头，依据多普勒效应1]制作的发射与接受装置。使用时将其安装在室内，当有物体在接发射头前移动时，由于频率的偏移，接收器可收到柏频超声波。经过信号处理，驱动继电器动作，从而实现声、光报警。该装置主要用于室内防盗，同时也可用于其它需要防护的场合。

Ultrasonic Intruder Alarm

This paper introduce a way to use the ultrasonicT/R head and ultrasonic's Doppler Effect to make an intruderalarm. When there is a moving body in front of the head, thealarm, which is kept inside a room, is to receive a beatfrequency. After processing the rceived signal, the receivingdevice is able to make a relay work. The device is mainlyutilized to prevent unexpected intruders from coming inside aroom. We can also use the device in those places wheredefence is needed.