APPLICATIONS OF TELEMETRY DATA ACQUISITION EQUIPMENT IN THE FIELD OF SPACE VEHICLES

Abstract

Generally, the data acquisition equipment used in space vehicles mainly consists of logic program control, multiplexer-encoder, output driver, power supply for dc conversion and so on. Today telemetry technology has been deeply concerned with computer science. So how to make the telemetry system more flexible and versatile and how to design a multiplexer-encoder (data collector or remote unit as is called in a programmable telemetry system) with good compatibility and powerful function has become one of the most important things of developing a new generation of telemetry system. In 1960s, most of the telemetry systems were of typical coded time-division multiplexing. The sampling program of this system is fixed and its bit rate and frame format are unvaried, so it is difficult for a system to accommodate the requirements of various kinds of measurements, especially when there are comparatively more parameters to be measured, and most of which are of slow-changing. As the sampling rate is designed in accordance with the upper-limited signal frequency that we need to measure, so the validity of the slow-changing data is very low. And onced the telemetry equipment has been developed, it is very difficult to change the sampling rate, the bit rate and the frame format. With the development of electronic devices, more devices can be integrated in a small chip, so the programmable telemetry had been pulled off in early 1970s. This article deals with mainly a few programmable multiplexer-encoders and microprocessor-controlled multiplexer-encoders used in our actual research work and applications.