This paper reports on the design considerations and implementations of construction of a receiver system for an infrared communication link using Light-Emitting-Diodes (LEDs). System configuration is non-directed line of sight (LOS) with single element receiver. The speed of the system constructed is 20 MHz (40 Mbps for on-off keying). In our design, the receiver consists of a multi-channel photo-detector array followed by multi-channels transimpedance amplifiers, a summer circuit for combining signals, low-pass filters(LPF) and high pass filters(HPF), and auto-gain control unit(AGC). The spectral match between photodiode and LED, looking angle of photodiode, rise time consideration of the photodiode, trade-off between transit rise time and photodiode effective area, etc, are also be discussed . A receiver module of speed response up to 20 MHz has been successfully constructed and the system is capable of receiving optical signal at a height of 2 m from the ceiling with coverage of a cell of 4 m in diameter.

Date Published: 18 October 2001
PDF: 8 pages
Proc. SPIE 4586, Wireless and Mobile Communications, (18 October 2001); doi: 10.1117/12.445247

Published in SPIE Proceedings Vol. 4586:
Wireless and Mobile Communications
Hequan Wu; Jari Vaario, Editor(s)