A Research On Some Key Techniques In The Integrated Base-band Of PM Mode About A Dual-mode Transponder

With the development of spaceflight technology and military need,TT&C technology has experienced the change from separate system to USB system and develop into Tracking and Data Relay Satellite System(TDRSS).At present time,the USB TT&C network is under construction and improvement in our country,but this system meets more and more challege with the rapid development made in spaceflight,so we should develop our own TDRS and work over a new TT&C system in order to meet the need of enlarging the range of TT&C network and the need of electro-counterwork.The research of transponder goes side by side with the TT&C technology,the tracking,telemetering and command signal are all modulated on a united carrier throught several subcarriers,and FDMA is adopted in USB system. The newly established TT&C system goes a different way with TDMA and PN code spread spectrum is used.therefore,it is of great significance to develop a dual mode transponder to made the two different system compatible.Based on the research of relevant data and present technology, the thesis discussed the configuration,structure and functioning of a new dual mode transponder with a universal flatform, and later in this thesis a SDR-based realization scheme about the integrated base-band of PM mode is also put forward, the thesis comes down to digitization of PM signal at IF,orthogonal DDC,demodulation of PM and PSK,process and transmission of Mono-tone,and synthesization of frequency etc.