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Flicker Prevention Through Edge-Pulse Modulation in a Visible Light Identification System

가시광 무선인식장치에서 가장자리 펄스변조를 이용한 플리커 방지

  • Lee, Seong-Ho (Department of Electronics and IT Media Engineering, Seoul National University of Science and Technology)
  • 이성호 (서울과학기술대학교전자IT미디어공학과)
  • Received : 2020.04.27
  • Accepted : 2020.05.07
  • Published : 2020.05.31

Abstract

In this study, we applied edge-pulse modulation to prevent the flicker of light-emitting diode (LED) light in a visible light identification system. In the visible light transmitter, positive pulses were transmitted at the edges of the low-to-high transition points, and negative pulses were transmitted at the edges of the high-to-low transition points of the non-return-to-zero (NRZ) data waveforms. In the visible light receiver, the NRZ waveforms were regenerated by making low-to-high and high-to-low transitions at the point of the positive and negative pulses, respectively. This method has two advantages. First, it ensures that the LED light is flicker-free because the average optical power of the LED was kept constant during data transmission in the transmitter. Second, the 120 Hz optical noise from the adjacent lighting lamps was easily cut off using a simple RC-high pass filter in the receiver.

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