基于单片机的超声波液位测量系统

介绍了超声波液位测量系统的工作原理和系统框图，给出了详细的超声波发射电路和环境温度采样电路。通过对接收信号采取一系列有效的处理方法：首先对接收信号采取STC(灵敏度时间控制)方式进行信号放大，接着对信号进行线性包络检波，最后采用微分电路和零点交叉检测，生成输出信号，基本上消隐了测量盲区和时间检测误差，并进行了温度补偿计算。采用模块化方式设计系统软件，成功地研制了基于单片机的超声波液位智能测量系统。实测表明，系统具有较高的测量精度和较强的适应性。

Intelligent System to Measure Liquid Height by Ultrasonic Based on Single-chip Microcomputer

The principles and the frame of the system to measure liquid height by ultrasonic is presented.The circuit of exciting ultrasonic and sampling environmental temperature is detailed.The sightless area and the time measure error are removed basically by an effective method of transforming received signal.Firstly,the received signal is magnified by the method of STC(Sensitivity Time Control).Secondly,a linear encircling demodulation is used on the magnified signal.Finally,the desired signal is attained by the method of differential circuit and zero-cross demodulation.At the same time,temperature error is compensated.Adopt modular programming and develop successfully this system on a single-chip microcomputer.The measure results show that the system can obtain higher precision and better adaptability.