electronic frequency counter

例句：

1. 1.The electronic frequency counter is used to measure the frequency of radio waves.
   电子频率计数器用于测量无线电波的频率。
2. 2. The electronic frequency counter was used to detect the presence of a nearby radio station.
   电子频率计数器被用来检测附近电台的存在。
3. 3. The electronic frequency counter was used to monitor the performance of the communication system.
   电子频率计数器被用来监控通信系统的性能。