Design And Implementation Of Digital Terminal Software For The Observation Of Radio Pulsar

In the current frontier research of Deep space explorations, pulsars are the priceless treasure. Some pulsars keep time better than the earth’s most accurate clocks.Its emission with high stability period pulse not only provides a natural time measuring tool, but also can be an effective probe to detect interplanetary electron density, interplanetary magnetic field and gravitational waves. In the development of pulsar research,the core of the problem is the improvement of observation ability and method. The radio pulsar observation system is the key equipment in the observation of the pulsar. Therefore, receiving digital terminal of radio pulsar observation has an important application value.Firstly, the research backgrounds of radio pulsar observation and oversea research status of digital terminal are introduced.According to different application requirements、two platforms of receiving digital terminal of radio pulsar observation are proposed respectively. The one is based on PCI+V5 architecture,and the other is based on ARM+V6 architecture.Then, signal processing algorithms are studied for the digital terminal based on PCI+V5 architecture.The method of Digital Down Converter (DDC) that is easy to implement in hardware is proposed.The simulation results verify its effectiveness and meet the desired requirements.Then, the software design of digital terminal for two platforms are developed.The functional modules in the first platform consist of hardware control, data packet storage, spectrum mapping and user business.Each part has been designed and implemented. Hardware control is based on PCI-bus mapping.Data packet storage and spectrum diagram drawing are realized in the way of independent thread. User business is implemented by MFC timer. The key technologies in software implement involve the threadencapsulation and the time function choice.Functional modules in the second platform are similar to these in the first one, however the implementation is quite different.According to the analysis of C/S architecture and B/S architecture,the Web software based on B/S architecture is adopted.The hardware driver,service software and data storage software are implemented respectively. The hardware driver is developed based on misc device driver.Service software is based on object-oriented thought and multithreading technology. And data storage software is realized based on Winpcap library.Finally, the digital terminals are tested in the aspects of data integrity and functionality. More the systems are tested in Shanghai Astronomical Observatory. The results verify that the system behaviors meet the desired requirements.