Authors : Duck-Ju Lee and Seong-Ho Lee
Abstract: In this study, we implemented a visible light communication system for indoor voice broadcasting using three-level Light Emitting Diode (LED) modulation. In the transmitter, two parallel FETs were used as a three-level LED driver whose current was proportional to the sum of the sync pulse and the data bits. In the receiver to recover the transmitted data, a two-diode circuit separated the three-level photodiode voltage into sync pulse and data bits. The data bits were coded in Manchester code, so that, the LED light would not flicker. The system configuration is very simple and easy to use because sync pulse and data bits are transmitted simultaneously by one LED array. This structure can be easily utilized to construct a wireless guidance system for product description using LED light at various exhibitions, department stores and shopping malls.
Duck-Ju Lee and Seong-Ho Lee, 2018. Indoor Wireless Voice Broadcasting System Using Three-Level LED Modulation. Journal of Engineering and Applied Sciences, 13: 3642-3650.