| This Dissertation use rebuild of Combined Telemeter System, which is the Subsystem of the RED-NINE system developed by the Aerospace Measure and Telecommunication Incorporated Company, as background, study and discuss Frequency Synthesize Technology. The mostly task is to study how to use the Direct Digital Synthesis technology to design and realize the high speed digital mid-frequency modulator, and give the answers of the problems which emerge in the development.Firstly, introduce the basic conception of the telemeter and the telecontrol system; discuss the common department of the telemeter and the telecontrol system, and the angle modulation used by it; summarize the structure and function of the telemeter and telecontrol.Secondly, introduce the frequency synthesis technology. It discusses some kinds of basic frequency synthesis technology such as direct, phase-lock, digital and direct digital frequency synthesis, then give the performance index of the frequency synthesis, and discusses the digital frequency synthesis technology in detail.Thirdly, give the way to how to design the digital mid-frequency modulator, discuss the design process of the system, and give the block diagram of it. It analyze the performance index of the mid-frequency modulator firstly, abased this, analyze the design of it, which include the AGC circuit,DDS circuit,and so on.Fourthly, discuss how to realize the digital mid-frequency modulator. At the start, introduce the AD9854, which is a DDS chirp, and then, discuss the realization process of the hardware and software of the system, such as realization of the AGC circuit, DDS circuit, state flow, and so on.Afterward, analyze the problems emerged in the debugging, and then to get out the way to disposal them.Finally, summarize this text, then put forward something that author ought to enhance.
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