The Possibility and Prospect of Adopting New Multiplexing Techniques in Telemetering

Abstract

Ordinarily, in telemetering systems people use FDM and TDM techniques for transmitting various signals from a great number of transducers. But neither in FDM nor in TDM there always exist some shortcomings, such as inter-modulation interference, oversampling, low efficiency of channel utilization and troubles in synchronization. In recent fifteen years, many new multiplexing techniques are proposed due to the development of satellite communications, such as multiple carrier system in DCP, which is often used in geostationary meteosat for collecting environment parameters of the earth surface, SCPC, SPADE and code division multiplexing by m-sequences, GOLD sequence, frequency hopping, Waith functions. In this paper, from the standpoint of telemetry, we discuss and compare the advantages and drawbacks of these methods in bandwidth utilization, capacity, interference, and the ratio between performance and cost when they will be used in telemetry.