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在固体与液体的超声检测中,常常需要通过超声换能器将一探测信号发出,然后再接收反射信号并进行处理.在这一过程中,先由超声换能器将电信号转换成超声波信号发出,该超声波信号至反射界面被反射后,反射波再由超声换能器转变成电信号.该电压信号幅度很小,仅有mv数量级,如何将此信号变成能与微机接口的电平将是个具有实际意义的问题.解决这个问题必须通过两个关键环节.其一是将电压信号放大到一定幅度;其二是将放大的信号整形,转换为可与微机接口的高低电平.第一个环节如图1所示,利用收录机集成电路μpc1018C实现信号的放大,可得到满意的效果,在外接+12V电压的情况下,放大后的电压峰峰值可达9V.具体原理见资料[1],不再赘述.下面着重探讨如何解决第二个环节.
In solid and liquid ultrasonic testing, it is often necessary to send a probe signal through an ultrasonic transducer and then to receive the reflected signal and process it.In this process, the ultrasonic signal is first converted by the ultrasonic transducer into an ultrasonic signal Issued, the ultrasonic signal to the reflection interface is reflected, the reflected wave and then by the ultrasonic transducer into electrical signals.The voltage signal amplitude is small, only mv orders of magnitude, how the signal into a computer interface with the level Will be a practical issue.To solve this problem must pass two key aspects.One is to amplify the voltage signal to a certain extent; the second is to enlarge the signal shaping, can be converted to high and low level interface with the computer. A link shown in Figure 1, the use of tape recorders integrated circuit μpc1018C signal amplification, can be satisfied with the results, in the case of external +12 V voltage, the amplified peak voltage up to 9V. See the specific principles of information [1 ], Will not repeat them. The following discussion focuses on how to solve the second part.