The Application And Implementation Of Nuclear Data Processing Based On Digital Signal Scrambling System

With the rapid development of micro-electronics, computer and networking technologies, the technologies such as nuclear data acquisition, data processing, the measurement results on-site display and data transmission are improved continuously. The general data can transmission in order to share by all means. Because nuclear data is related to the country's secrets, it is particularly important that how to ensure the confidentiality and safe transfer of nuclear data.The Conditional Access System (CAS), which has been applied successfully in the field of digital television, can effectively ensure the security of data in time and handle amounts of data. The CAS guarantees that those entitled customers can only access data. The CAS scrambles data streams with control word at head-end and sends the encrypted control word together with data streams. It is responsibility to make sure entitled customers can only decrypt the control word and descramble data streams. The technology, which accomplishs the confidentiality of data, can process digital signal ,a nd it is an effective way of encrypting nuclear data. This thesis explained the application of this technology in nuclear data processing and transmission, to achieve the security of nuclear data.Firstly,the principle of CAS is introduced in this paper. The sub-system (Scrambling System) is completed by using three-encryption and a design of Scrambling System is proposed. The ARM9 is used as control unit to achieve the network communication with the PC, the configuration of equipment and the generation and processing of auxiliary information; the FPGA is used for the logic and data processing to realize the algorithm of signal scrambled and reusing of information. The design of the hardware is completed which includes the design of the ARM9 control unit, the FPGA logic and signal processing unit, data output unit and the other unit.Secondly, the design and development of embedded Linux system are introduced in this article. The process includes the following:Setting up the cross compiling environment: The cross compiling environment includes the embedded developing tools. Setting up cross compiling environment is to compile and install the tool-chain.Porting of the OS kernel: It is the important step of the embedded development. Reconfiguring the kernel makes it meet specific requirement and then recompilling the kernel generates the excitable OS kernel image file.Porting of the file system: File system is an effective and necessary way to manage the data. Porting of the file systems includes making file system's image, assigning the memory in a flash chip and the valid cooperation between the file systems and the embedded OS.Drivers design: Drivers are a bridge of communication between OS and hardware. Drivers design is to implement writing and reading control functions which are applied with specific hardware and offer a common interface for the OS.Thirdly, the design, simulation and programming of the FPGA in this paper are introduced.Finally, we achieved the expected goal by the performance of this system test in this paper.