VLBI相关处理机是甚长基线干涉测量（Very Long Baseline Interferometry，VLBI）数据处理中的核心设备。数据回放接口（Playback Interface，简称PBI）是VLBI相关处理机最前端的数据预处理单元，它与数据回放设备（磁带机、硬盘阵列等）通过专用接口相联接，负责对接收到的数据帧进行解码、校验、流量控制、差错纠正、时间同步以及并—串转换等逻辑运算，为后续计算单元提供连续、准确、可靠、完整的数据流。 论文从VLBI的相关背景知识入手，介绍了VLBI相关原理、VLBI相关处理机以及相关处理对数据回放的要求。根据这些要求，对数据回放接口单元内部进行模块划分，分析各模块的逻辑功能以及模块之间的接口时序。 在理论分析之后，论文详细论述了以华邦公司的微控制器—W77LE58和Xilinx公司的百万门FPGA—XC2V3000为构架的硬件系统，利用C和VHDL硬件描述语言，在Keil和ISE开发环境下，对微控制器和FPGA进行设计，实现32位并行数据，在32MHz同步时钟驱动下，按参数要求进行相应的通信及逻辑运算处理的过程。文中给出了软件流程图、模块内部功能结构及模块实现的逻辑框图。 论文最后还给出了测试过程中通过逻辑分析仪记录的接口时序以及在“嫦娥一号”绕月探测工程中，相关处理机数据处理的结果，以此来证明数据回放接口设计的正确性。
其他摘要
Correlator is the core unit of VLBI (Very Long Baseline Interferometry) data processing equipment. The Data Playback Interface (PBI) is a data pre-processing unit in the front of VLBI correlator, which is connected to the data playback equipment (such as tape machine, disk array) by specific interface. In order to provide continuous, accurate, reliable and integrated data stream to the follow-up units, the PBI unit takes charge of decoding, check, flow control, correction, time synchronization and parallel-to-serial conversion of the data frames. This paper begins with the VLBI background, and then introduces the theory of VLBI, the construction of VLBI corrlator and the VLBI correlator functional requirements for the PBI unit. According to these requirements, the PBI unit can be divided into different modules. Then, the logical function and interface timing between modules are analyzed. After the above theoretical analysis, the paper describes the hardware system which is based on WinBond’s W77LE58 Microcontroller and Xilinx’s million-gate FPGA XC2V3000. The system is developed in Keil with Standard C, and ISE using VHDL , which can implement the corresponding communication and logic operation according to parameters. The data width is 32-bit and the system is driven by a 32 MHz synchronous clock. Software flow chart, logical diagrams and constructional details of the modules are also presented in the paper. Timing of the interface recorded by logical analyzer and the practical data processing results form correlator of Chinese Lunar Exploration Program (CLEP) prove the logical validity of PBI unit.
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