signal waveform

例句：

1. 1. The police officer used his flashlight to signal the driver to stop.
   警察用他的手电筒示意司机停车。
2. 2.The new product is a signal of the company's commitment to innovation.
   新产品是公司致力于创新的信号。
3. 3. The traffic light is a common signal for pedestrians and vehicles.
   交通灯是行人和车辆的常见信号。