Browsing by Author "Liu, Yu-Feng"

Now showing 1 - 2 of 2

Demonstration of Using Digital FIR Filter and Matched Filter to Increase Data Rate in Visible Light Communication
(2013)
Liu, Yu-Feng
;
Yeh, Chien-Hung
;
Chow, Chi-Wai
;
Huang, Po-Yen
;
Liu, Yang
Using digital-filters in time domain are demonstrated to enhance the modulation-speed of 1 MHz bandwidth white LED communication. Digital FIR filter and matched filtering are used to reduce the inter-symbol-interference (ISI). Hence, 20-Mbps is achieved by using 4-ASK modulation.
QPSK Modulation for AC-Power-Signal-Biased Visible Light Communication System
(2013)
Liu, Yu-Feng
;
Yeh, Chien-Hung
;
Chow, Chi-Wai
;
Liu, Yang
;
光電工程學系
With the integration of light emitting diode (LED), visible light communication (VLC) can provide wireless communication link using the lightning system. Due to the consideration of power efficiency, AC-LED has the design of reducing energy waste with alternating current from the power outlet. In this work, we propose an AC-power-signal-biased system that provides communication on both DC-LED and AC-LED. The bias circuit is designed to combine AC-power signal and the message signal with QPSK format. This driving scheme needs no AC-to-DC converters and it is suitable for driving AC LED. Synchronization is completed to avoid threshold effect of LED.