PCM/PPK telemetry system is a multi-nary pulse modulation system.It is commonly used to transmit high-accuracy time information and some express signals.To the issue of security that telemetry data is transmitted in t...PCM/PPK telemetry system is a multi-nary pulse modulation system.It is commonly used to transmit high-accuracy time information and some express signals.To the issue of security that telemetry data is transmitted in the open space,a data encryption scheme in the PCM/PPK telemetry system is proposed.In this scheme,the PCM data of signal source are encrypted by stream cipher in which key streams are generated with clock control LSFR.The scheme can save system resource in the dual-modulation compound telemetry system.A backward key synchronization scheme is also proposed,which has the property of strong real-time and easy to implement.A simplified simulation model of PCM/PPK remote system is established based on the actual framework of telemetry system,and the model is simple and easy to simulate.The error performance of the system is analyzed in theory and tested by computer simulation.Also the security of the system is analyzed.The simulation and analysis results show that the encryption scheme can ensure the security of the telemetry data and does not cause error-diffusion.展开更多
在分析遥测接收系统工作原理的基础上,深入研究了CORDIC(COordinate Rotation Digital Computer)算法的解调技术.当输入为正交中频(IF)信号和对应的时钟信息时,输出即为输入瞬时信号对应的瞬时相位,但在信道没有延迟时,其抗噪性能不如...在分析遥测接收系统工作原理的基础上,深入研究了CORDIC(COordinate Rotation Digital Computer)算法的解调技术.当输入为正交中频(IF)信号和对应的时钟信息时,输出即为输入瞬时信号对应的瞬时相位,但在信道没有延迟时,其抗噪性能不如相干解调.在此基础上设计了一种改进的CORDIC差分鉴频解调算法,得到瞬时相位后,在数字域作1阶差分完成信号鉴频,保证了在信道没有延迟的情况下信号的抗噪性能.通过仿真实验证明了算法的合理性.展开更多
文摘PCM/PPK telemetry system is a multi-nary pulse modulation system.It is commonly used to transmit high-accuracy time information and some express signals.To the issue of security that telemetry data is transmitted in the open space,a data encryption scheme in the PCM/PPK telemetry system is proposed.In this scheme,the PCM data of signal source are encrypted by stream cipher in which key streams are generated with clock control LSFR.The scheme can save system resource in the dual-modulation compound telemetry system.A backward key synchronization scheme is also proposed,which has the property of strong real-time and easy to implement.A simplified simulation model of PCM/PPK remote system is established based on the actual framework of telemetry system,and the model is simple and easy to simulate.The error performance of the system is analyzed in theory and tested by computer simulation.Also the security of the system is analyzed.The simulation and analysis results show that the encryption scheme can ensure the security of the telemetry data and does not cause error-diffusion.
文摘在分析遥测接收系统工作原理的基础上,深入研究了CORDIC(COordinate Rotation Digital Computer)算法的解调技术.当输入为正交中频(IF)信号和对应的时钟信息时,输出即为输入瞬时信号对应的瞬时相位,但在信道没有延迟时,其抗噪性能不如相干解调.在此基础上设计了一种改进的CORDIC差分鉴频解调算法,得到瞬时相位后,在数字域作1阶差分完成信号鉴频,保证了在信道没有延迟的情况下信号的抗噪性能.通过仿真实验证明了算法的合理性.
