A Research On The Testing System Of Sub-carrier In Telemeter And Telecommand System

The united-carrier telemeter and telecommand system of satellite uses carrier and sub-carrier to complete all the function. The measuring of parameters of the sub-carrier is to ensure the normal running of the system. This article's research is on the realization of the testing system of the sub-carrier and some key techniques are designed and analysed. The main content of this article includes:1. Basing on the required function, this article puts forward the testing targets, gives the signal flow and designs the convenient and brief menu.2. Because the analysis in the time field is the main testing function, this article completes the designing and realization of the main function of this module. Different from springing signal by hardware method which is used in oscillograph and logic analyser, the method of springing by software based on sampled data is realized, and the emphasis is on the realization and the working flow of sequence-spring mode. In addition, the method selection and realization of inserting are introduced, with the imitation of it carried through.3. Because the analysis of spectrum is the main content of getting the signal's features, this article analyzes the main function of spectrum analysis. Based on the signal feature and testing commands, the method of spectrum estimation is selected among many methods by simulation. Different from the spectrum analyser which uses hardware, the switch of frequency span is designed by software, and the imitation is completed.4. Different with the traditional method of the measuring of frequency stability by means of special equipment, a new digital method based on sampled data is designed in this article and the theory, means and performance of it is put forward.5. The ADC parameters are selected according to the aspects of the required amplitude revolution to display signal, of the required quantify precision in inserting and spectrum analysis. The influence of the noise in the time field to the computation of inserting and spectrum analysis is also discussed. And the main performance and indexes of the testing system are summarized in this part.6. The elemental designing of the noise switch is discussed in the article, and the theory and process of the switch from WGN to white Rayieigh noise are introduced by use of the WGN producer in existence.