The Second Modulation Signal Based On The Fm / Psk Satellite Telemetry Signal Demodulator Design And Realization

The human society is based on the information communication. So communication greatly drives the civilization, progress and development of human society. In the domestic and international long-distance and medium-distance communication areas, satellite communication has become an important method., and satellite communication technology is still in progress. Nations in the world, especially the developed nations still make large investment in the research and development of new technologies and components in order to decrease cost and enlarge the application scope. Specialists continue to make great effort in modulation and demodulation technologies . Telemetry, known as remote measurement, means remotely measuring characteristic parameters of targets and transferring the measurement results back to receiving point for analysis. The telemetry technology is an outcome associated with highly-developed and closely-integrated remote detection technology, autonomous control technology and RF information transfer technology and is the long-range extension of human sensing and control functions. The study of this paper originates from the telemetry signals of some LEO satellites that are needed for reception by one satellite signal receiving station. The modulation types of the telemetry signals of these satellites are mainly the same, that is PCM/PSK/FM modulated signals, but the specific parameters are different. More specifically, the subcarrier frequencies and data symbol rates are different. The author provides a telemetry demodulator for PSK/FM modulation signal according to the requirements of ground stations.This paper firstly illustrates the importance of two-leveled modulation signals of this type in the telemetry system and describes the task for the implement of telemetry demodulator which is needed in the PSK-PCM telemetry system block diagram. Secondly ,this paper provides the design block diagram of the telemetry demodulator that is made up of the IF unit, the FM demodulation unit, the subcarrier demodulation unit and the digital clock phase lock unit. Furthermore, this paper uses the way of "first general illustration then raising actual design" to discuss the above-mentioned four units. Lastly this paper provides the photos of this telemetry demodulator, concludes the relevant key technologies and innovation points, introduces the performance that is related to these technologies, and discusses the economic prospects that are associated with the wide use of this kind of telemetry demodulator.