超声波筛分系统扫频式信号源设计  

Design of Sweep Frequency Signal Source for Ultrasonic Screening System

作　　者：白林锋 王泽华 王应军[1] BAI Linfeng;WANG Zehua;WANG Yingjun(School of Information Engineering,Henan Institute of Science and Technology,Xinxiang 453003,China)

机构地区：[1]河南科技学院信息工程学院,河南新乡453003

出　　处：《电声技术》2020年第7期72-75,79,共5页Audio Engineering

基　　金：2020年河南省重点研发与推广专项(科技攻关)项目(202102210113);2019年河南省省重点研发与推广专项(科技攻关)项目(192102210084)。

摘　　要：针对筛分超声波换能器机电转换效率低下的问题,设计一种扫频式超声波信号源,使换能器工作在自身谐振频点附近,以获得较大机电转换效率。利用A-D转换器输出一个扫频电压,控制精密压控振荡器产生扫频信号,再利用单片机内部定时器监测信号的中心频率,并与实际换能器谐振频率比较,达到换能器自动锁定和自动修正的目的。应用测试表明,扫频信号源中心频率能够自动跟踪换能器谐振频率的变化,锁定和修正后误差小于50 Hz,解决了超声筛分系统因信号源与换能器之间失谐导致筛分效率下降的问题。Aiming at the problem that low electromechanical conversion efficiency of sieving ultrasonic transducers,a swept-frequency ultrasonic signal source is designed,which can make the transducer work near its own resonance frequency point to obtain greater electromechanical conversion efficiency.Using the AD converter output a frequency sweep voltage to control the precision voltagecontrolled oscillator to generate a frequency sweep signal,and then using the internal timer of the microcontroller to monitor the center frequency of the signal,and compare it with the actual transducer resonance frequency to achieve the automatic lock and Automatic correction purpose.Application tests show that the center frequency of the swept signal source can automatically track the change of the resonant frequency of the transducer,and the error after locking and correction is less than 50Hz,which solves the problem of the ultrasonic screening system due to the detuning between the signal source and the transducer.The problem of reduced efficiency.

关 键 词：超声波筛分 扫频信号源 压频转换器 谐振频率 

分 类 号：TP29[自动化与计算机技术—检测技术与自动化装置]