基于强方波脉冲发射技术，配合高增益高信噪比接收放大器、高速低功耗数字处理系统以及专用低频探头，对大直径石墨棒进行超声穿透法检测。结果表明：采用强方波脉冲发射技术对小厚度（50 mm以下）石墨件检测时，灵敏度余量比配合普通超声探头的超声检测仪高55 dB，可解决普通超声检测仪无法检测340 mm左右直径石墨棒的难题。

A research was performed on high square-wave pulse emission technology. Together with high-gain high signal-noise ratio amplifier, high-speed low-power consumption digital processing system and dedicated low-frequency probes, large-diameter graphite rod was inspected by ultrasonic through-transmission method. Comparision test was carried on using common ultrasonic flaw detector with low-frequency ordinary probe. The result shows that:using this new technology, the surplus sensitivity is two times of normal ultrasound method while using this new technology; and the 340mm large diameter graphite rod inspection problems are successful resolved.