Short-range audio transfer through 3 Watt white LED on LoS channels

Abstract

We have performed the short-range audio transfer system through a visible light as a medium using 3 Watt white phosphor LED, where the channel used is line-of-sight (LOS). The audio signal is coming from the PC and processed by analog front-end (AFE) transmitter which consists of the preamplifier, summing circuit, and buffer. The audio input signal amplitude can be adjusted manually by tuning the DC voltage level. In AFE receiver, TIA is used as a current to voltage converter. We used the summing amplifier circuit to set the signal DC level and positioning adjustment. The final block on the receiver circuit is a buffer and connected directly to the loudspeaker. The proposed AFE transceiver circuit has bandwidth around 300 kHz. In this paper, we also investigate the effect of a color filter using mica paper in free space between the transmitter and the receiver.