TY  - JOUR
T1  - Indoor Wireless Voice Broadcasting System Using Three-Level LED Modulation
AU - Lee, Duck-Ju AU - Lee, Seong-Ho 
JO  - Journal of Engineering and Applied Sciences
VL  - 13
IS  - 10
SP  - 3642
EP  - 3650
PY  - 2018
DA  - 2001/08/19
SN  - 1816-949x
DO  - jeasci.2018.3642.3650
UR  - https://makhillpublications.co/view-article.php?doi=jeasci.2018.3642.3650
KW  - Visible light communication
KW  -three-level modulation
KW  -LED
KW  -indoor voice broadcasting
AB  - 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.
ER  -