Protection circuitry for high frequency ultrasonic NDE
Protection circuitry for high frequency ultrasonic NDE
复制标题
高频超声波无损检测保护电路
DOI：
10.1063/1.1291315
复制
发表时间：
2000
影响因子：
0.3
通讯作者：
B. Starkoski
中科院分区：
文献类型：
--
作者：
N. C. Chaggares;R. K. Tang;A. Sinclair;F. Foster;Kasia Haraierciwz;B. Starkoski
大多数商用超声波无损检测设备采用电压尖峰来刺激压电换能器。为了保护信号处理单元免受这个尖峰的损坏，脉冲发生器接收器中包括一个电压限制器或“二极管钳位”，并限制到达放大器或示波器的电压。在这个项目中，这种限制器对高频（50-100 MHz范围）超声回波的有害影响已经被量化：这些影响包括频率内容的显著失真，以及导致时序分辨率下降超过2倍的振荡。为了解决这些问题，设计了一种高压高频开关来取代电压限制器；开关引导高压尖峰远离信号处理/显示单元，朝向阻抗匹配的终端。已经建立了一个原型电路，基于两个高压MOSFET作为双极刺激脉冲的开关。降低回波失真，改善…
Most commercial ultrasonic NDE equipment employs a voltage spike to stimulate a piezoelectric transducer. To protect the signal processing unit from damage from this spike, a voltage limiter or “diode clamp” is included in the pulser-receiver, and limits the voltage reaching the amplifier or oscilloscope. In this project, the deleterious effects of such limiters on the ultrasonic echo in the high frequency (50–100 MHz range) have been quantified: these effects include significant distortion in the frequency content, and oscillations causing a drop in timing resolution by over a factor of 2. To address these problems, a high-voltage high-frequency switch has been designed to replace the voltage limiter; the switch directs the high-voltage spike away from the signal processing/display unit, towards an impedance-matched termination. A prototype circuit has been built, based on two high-voltage MOSFET’s acting as a switch for the bi-polar stimulation pulse. The reduction in echo distortion and improvement in ...