demodulator of FM signal

例句：

1. 1. The car's radio is tuned to the AM station.
   这辆车的收音机调到AM频道了。
2. 2. The police are monitoring an FM signal for any suspicious activity.
   警方正在监控一个调频信号，寻找任何可疑活动。
3. 3. We need to tune in to the FM signal to receive the news broadcast.
   我们需要调频来接收新闻广播。