目前白光LED(发光二极管)广泛应用于照明, 而基于白光LED的可见光通信技术应用前景巨大。文章利用白光LED作为信号传输媒介设计了短距离传输系统, 发送端采用PWM(脉冲宽度调制)对音频信号和环境温度信号进行调制, 接收端采用电流反馈电路和电压放大电路提高PWM波峰值的动态范围, 利用STM32对光脉冲进行解调。该系统采用时分复用方式实现了短距离实时传输一路300～3 400 Hz的音频信号和一路数字信号, 传输后的波形在示波器上无明显失真。

Currently, white LED is widely used in lighting. Simultaneously, it has also achieved success in the area of Visible Light Communication (VLC) technology. In this paper, a short distance transmission system is designed by using white LED as the signal transmission medium. Pulse Width Modulation (PWM) is applied to modulate the audio signal and the ambient temperature signal. At the receiver side, current feedback circuit and the voltage amplification circuit are utilized to enhance the dynamic range of the PWM wave peak value. Then we use STM32 to demodulate the optical pulses. We also use Time-Division Multiplexing (TDM) technology to realize the real-time short-distance transmission of audio signals and digital signals from 300 to 3400 Hz. The results show that the waveform has no obvious distortion on the oscilloscope after the transmission.