undamped medium frequency elec-trotherapy

例句：

1. 1. The undampedoscillator produces a clean, sharpsound.
   未受扰动的振荡器产生清晰、尖锐的声音。
2. 2. Theundamped spring isable to return to its originalshape after being compressed.
   未受扰动的弹簧在压缩后能够恢复到原始形状。
3. 3. The undampedsystem will respond instantly to any changes inthe input signal.
   未受扰动的系统会立即对输入信号的任何变化做出响应。