line frequency

例句：

1. 1.The line frequency is 250 kHz.
   线路频率是250 kHz。
2. 2.The line frequency is critical for the operation of the communication system.
   线路频率对于通信系统的运行至关重要。
3. 3. The line frequency can be adjusted to optimize signal transmission.
   线路频率可以调整以优化信号传输。