• THE APPLICATION OF DIGITAL DEMODULATION TECHNIQUE FOR FREQUENCY MODULATION SIGNAL IN TELEMETRY RECEIVER

      Peng, Song; XiaoLin, Zhang; Xue, Cao; Xia, Qi; North China University of Technology; Beijing University of Aeronautics and Astronautics; China Luoyang Optoelectro Technology Development Center (International Foundation for Telemetering, 2004-10)
      Combined with an example of digital telemetry receiver design, this paper mainly discusses the application of software radio in telemetry receiver. The paper begins with an introduction of applying high efficiency digital filter and math analysis in quadrature digital frequency modulation and demodulation to digital frequency conversion technique. Next, Simulink/Matlab is used to simulate digital telemetry receiver. The method of simulation, analysis and calculation of performance and result of simulation are all available. In the end, the paper discusses digital telemetry receiver design and implement by making use of software radio technique, the circuits apply HSP50214 chip of Intersil Co., CPLD implements of Altera Co. and PC Bus. The sample is an expansion card for personal computer. Result of test, performance of the receiver and conclusion are given out, which show fine performance of receiver and can be apply to practice. The lever of this technology has reached first class in the world.
    • THE BASE STATION TELEMETRY DATA PROCESSING SYSTEM FOR UNMANNED HELICOPTERS

      Bin, Xu; XiaoLin, Zhang; Guolei, Lu; Weiwei, Hu; Beihang University (International Foundation for Telemetering, 2004-10)
      This paper discusses the design and implementation of the base station telemetry data processing system for the unmanned helicopter. The system designed is composed of code synchronizer, decoding and frame synchronizer as well as PCI bus interface. The functions of the system are implemented with very large integrated circuits and a standard PCI inserted card that is compact and easy to install. The result of flight performance tests shows that the system is reliable and can satisfy the requirements of telemetry system for unmanned helicopters.
    • THE RESEARCH ON THE HSP50214 PDC CHIP APPLYING TO FDM TELEMETRY SYSTEM

      Peng, Song; XiaoLin, Zhang; Wei, Zhang; North China University of Technology; Beijing University of Aeronautics and Astronautics (International Foundation for Telemetering, 2004-10)
      The content of this paper is putting forward an idea that applies the software radio technique to the subcarrier demodulation of frequency divided multiplexing telemetry system. Firstly, the article explains the basic thought and application of the software radio. It introduces the main function and the use of the programmable downconverter in HSP50214/ HSP50216. Secondly, it discusses the merit and shortcoming about the method of the subcarrier demodulation of frequency divided multiplexing telemetry system in common use. Finally, the article aims at ± 7.5% proportion bandwidth FM subcarrier channels that in common use in the military standard, introducing HSP50214/HSP50216 programmable downconverter in achievement of design and simulation result. The main problems in the design are discussed and a conclusion obtained.
    • THE TIMELINESS OF ASYNCHRONOUS PACKET MULTIPLEXING IN SWITCHED ETHERNET

      Qiao, Li; XiaoLin, Zhang; Huagang, Xiong; Yuxia, Fei; Beijing University of Aeronautics & Astronautics (International Foundation for Telemetering, 2004-10)
      Powered by single-segment switched interconnection, Ethernet can be used in time-critical data acquisition applications. Unlike synchronous time division multiple access, asynchronous packet streams result in congestions and uncertain multiplexing delays. With the delay analysis in the worst case and probabilistic guaranteeing conditions, we restrict the packet-sizes, intervals or traffic burstiness a priori to regulate delay deviations within acceptable scales. Some methods of combinatorics and stochastic theory, e.g. Cumulant Generating Function and the Large Deviation Principle, are used and verified by some simulation-based computations. The influence of time varying delay for telemetry applications is also discussed in some sense.