The red light is a signal to stop.

这个红灯是停车的信号。

He waved his hand as a signal to start.

他挥手作为开始的信号。

Compand the audio signal to reduce noise.

压缩和扩展音频信号以减少噪音。

If you need help, signal to the lifeguard.

如果你需要帮助，向救生员示意。

The device output a signal to the monitor.

设备向显示器输出了一个信号。

It takes only 200 milliseconds for the signal to travel.

信号传输只需200毫秒。

The engineer modulated the signal to reduce interference.

工程师调节了信号以减少干扰。

This sensor sends a control signal to the main controller.

这个传感器发送一个控制信号到主控制器。

The scientist amplified the signal to get a clearer reading.

科学家放大了信号以获得更清晰的读数。

This device needs a stable control signal to function properly.

这个设备需要一个稳定的控制信号才能正常工作。