Delta-Sigma Modulated Visible Light Communication Illumination System Using a Projector with the Digital Micro-Mirror...

Area of Science:

• Optical Communications
• Signal Processing
• Digital Systems Engineering

Background:

• Visible Light Communication (VLC) offers a promising alternative for high-speed data transmission.
• Digital micro-mirror devices (DMD) enable multi-directional signal projection.
• Previous VLC methods using DMDs focused on general data transmission.

Purpose of the Study:

• To extend existing DMD-based VLC technology for audio signal transmission.
• To implement and evaluate delta-sigma modulation (DSM) within a VLC framework.
• To develop a low-power, multi-directional audio communication system.

Main Methods:

• Utilized a digital micro-mirror device (DMD) projector for VLC signal generation.
• Employed delta-sigma modulation (DSM) for digitally encoding audio signals.
• Designed and tested two DSM variants: pulse width modulation (PWM) and pulse density modulation (PDM).
• Constructed a prototype DSM-VLC system with simple analog receiver circuits.

Main Results:

• Successfully transmitted multiple audio signals in different directions simultaneously.
• Verified that the DSM-VLC system achieves low power consumption due to simple receiver circuits.
• Experimental results closely matched simulation predictions.
• Pulse density modulation (PDM) demonstrated higher efficiency than pulse width modulation (PWM) concerning DMD switching frequency.

Conclusions:

• The proposed delta-sigma modulation VLC (DSM-VLC) system effectively transmits audio signals in multiple directions.
• The system's low-power design and directional capabilities make it suitable for specific applications.
• PDM-VLC is more efficient than PWM-VLC for DMD-based systems.