A multichannel short range bidirectional infrared link with code division multiple access (CDMA)

In this paper, we present an infrared transmission system meant for indoor applications. It is based on CDMA technology and therefore it is highly resistant to environmental interference such as fluorescent light. A very simple synchronization scheme is employed based on a slight detuning of quartz oscillators in the terminals and central station. The following issues are discussed: principle of operation, link configuration, code selection, synchronization, and range of operation. Measurement results are also presented.