Design Of X-ray Pulsar Signal Simulator

With the development of science and technology, human exploration of deep space has a special significance in twenty-first century. Recently, the discovery of X-ray pulsar has pointed out a direction for the deep space exploration of human beings. However, the research on X-ray pulsar is still facing a series of problems to be solved. Therefore, it is of great significance and prospect to do trials use X-ray pulse signal simulator in the ground. Through the ground test, it can be found that the failure of the detector may occur in advance, and the performance of the detector is tested. Through this method, the accident rate and the cost will be reduced to a great extent.This paper mainly focuses on the theoretical basis and the hardware system design of X-ray pulsar signal simulator. Firstly, this paper summarizes the present situation of the research on the pulse star, and expounds the background and significance of this design, and that systematically introduces the evolution of pulsars, nomenclature and classification of the basic theory. Secondly, explains the theoretical basis of the simulator design in detail, the direct digital frequency synthesis technology. According to the characteristics of X-ray pulsar signal, an improved digital signal synthesis technique is proposed.In the hardware design of X-ray pulsar signal simulator, the hardware system is divided into three core modules: information processing and parameter calculation, digital signal synthesis and data conversion. The information processing and parameter calculation module is based on the digital signal processor, and the main parameters of the information processing and phase are calculated. Digital signal synthesis module is based on field programmable gate array(FPGA) as the core, the digital signal synthesis of X-ray pulsar signal simulation is accomplished, and the rest of the chips on the simulator are controlled by FPGA. The digital analog converter is the core of digital signal to analog signal module,and accomplish the output from digitai signal to analog signal. Secondly, the design process combines with X-ray pulsar signal characteristics, according to the internal and the input and output interface of each module of the electrical characteristics and specifications, complete hardware system design.During the PCB design, full consideration of signal integrity, power integrity and other related theories.In combination with the actual environment,the reflection and crosstalk simulation is traversed by the route.And get the best routing scene and constraints, and that the physical design of the hardware system are obtained.Finally, according to the X-ray pulsar navigation principle,pulse star phase orbital modulation and phase calculation algorithm of software design are given in the process of using hardware simulator to generate X-ray pulsar simulation, and the main module of the system hardware are tested detailedly. Test results show that the design of the hardware system can support the needs of X-ray pulsar signal generation.