Research Of Complex Battlefield Electromagnetic Environment Simulation System

As a new research project, Battlefield Electromagnetic Environment Simulation System has a great requirements and wide application prospects in national defense construction. This system can provide a vivid battlefield electromagnetic environment for communication countermeasure experiment, it also can provide a signal scene which is similar to practical working environment for the research, development and test of civil communication products so as to evaluate the system specifications and performances. But the present development of this system is a challengeable subject at home and abroad because it involves complex signal processing and hardware design techniques.The research of this subject concentrates on dynamic background signal of the modern complex battlefield electromagnetic environment, and the design and realization of this system is based on Software Radio.This paper presents the design idea and design plan of the system on the basis of the introduction of the research background of the subject and the development status of communication background signal simulator at home and abroad and the analysis of the performances of several signal simulators of communication background which are developed overseas. It contains the analysis and the determination of the communication interference signals and its modulation mode, and the determination of the system constitution and the system principle block diagram on the basis of the present of the main functions and technical index of the system. This plan has the both functions of the software and the hardware. Its processor is digital signal processor (DSP); The multiple-waveform signals are generated by the direct digital frequency synthesis (DDS) technology, and the background speech signal is designed by speech signal processor; The Peripheral I/O Interface function such as the control of the background signal and the ports extension of multi serial ports, keyboard ports and LCD ports are carried out by ISP technology.First, this paper introduces the waveform generation method by DDS, and concludes its characteristics after the analysis of its principle, structure advantage and disadvantage. After the analysis of the leading chips, this paper presents the multiple-waveform signals plan based on AD9913. According to the analysis of spurious noise existed in DDS, an elimination method is put forward.Subsequently, this paper proposes the design plan which is based on the speech signal processor after the introduction of the design method of the speech generation module. The emphasis is the hardware circuit design.Then, This paper proposes the design of system logical control. The logical control of the system is accomplished by in-system programmable technology. The basic principle, device structure and design flow of the system are all described in this paper.This paper also puts stress on describing the design of the control system. According to the request of the system, the TMS320C5409 processor is selected as the control chip after analyzing its characteristic, performance and function block diagram. On the basis the hardware circuit of the control system and the interface circuit are put forward in this paper.Finally, this paper introduces the debugging of the system, especially the debugging of audio-CODEC interface. An improved method is also present in this paper.