Direct digital synthesis and current mirror based software defined general purpose visible light communication transmitter

In this paper, a visible light communication transmitter using a LED matrix with low-cost LEDs is shown. This design use a DAC to control the LED drivers, through a discrete component current mirror circuit. The DAC is controlled using an FPGA, which together works as a highly configurable direct digital synthesiser. The design proposed in this paper is thus well suited as a transmitter node in a software defined radio using visible light communication. In this paper, we describe the design, and show its behaviour when programmed to transmit a number of carriers modulated with amplitude and phase modulation schemes.