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形成指数衰减形脉冲波。在有示波管的超声波仪器中,时间脉冲信号同时送入锯齿波扫描电路,产生同步锯齿波信号,该信号加到示波管的水平偏转板上。由接收探头来的超声波信号经放大后,加在示波管的垂直偏转板上。于是示波管显示接收探头处的超声波波形。超声波由发射探头传播到接收探头的时间t可由示波管上的时标读出,见图3。在t中还要扣除信号在导线中的传播时间。在没有示波管的超声波仪器中,时间
Form exponential decay pulse. In oscilloscope ultrasonic instruments, the time pulse signal is fed into the sawtooth sweep circuit simultaneously to produce a synchronized sawtooth signal that is applied to the horizontal deflection plate of the oscilloscope. The ultrasonic signal from the receiving probe is amplified and added to the vertical deflection plate of the oscilloscope. The oscilloscope then shows the ultrasonic waveform at the receiving probe. Ultrasonic wave transmitted from the transmitting probe to the receiving probe t can be read by the time-scale on the oscilloscope, see Figure 3. In t also deduct the signal propagation time in the wire. In the absence of oscilloscope ultrasonic equipment, time