H wave

例句：

1. 1. The H waveis a type of electromagnetic wave thattravels in the same direction as theEarth's magnetic field.
   H波是一种电磁波，沿着地球磁场的方向传播。
2. 2.In radio engineering, H waves are usedto transmit signals over long distances withoutinterference from other signals.
   在无线电工程中，H波用于在没有其他信号干扰的情况下，远距离传输信号。
3. 3. The Hwave has been used for communication purposes sincethe invention of the telegraph.
   自电报发明以来，H波就被用于通信目的。