FSK

例句：

1. 1.FSK is a popular method of communication in China.
   FSK是中国常用的通信方法。
2. 2. The FSK system allows for efficient data transmission over long distances.
   FSK系统允许在长距离上高效地传输数据。
3. 3.In FSK, the signal strength varies with time to distinguish between different channels.
   在FSK中，信号强度随时间变化以区分不同的频道。