Research on FM Telemetry Software Demodulation Algorithms

Aimed at the problem that the demodulation threshold of non-coherent demodulation technology of PCM/FM telemetry system using frequency modulation in the present situation of aerospace measurement and control is higher, research a kind of multiple symbol detection based on maximum likelihood thought (Multi-Symbol Detection, MSD) demodulation method. This paper introduces the principle of multiple symbol detection and aiming at the shortcomings of the previous synchronization method, studies a kind of symbol decision process and synchronization of the combination of synchronization method.

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Study of Reentry Telemetry Signal in the Environment of Soft Demodulation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.989-994.3926 ◽

2014 ◽

Vol 989-994 ◽

pp. 3926-3929

Author(s):

Gang Fu ◽

Min Tao ◽

Qian He

Keyword(s):

Phase Characteristic ◽

Telemetry System ◽

Test Results ◽

Signal Phase ◽

Signal Noise ◽

Soft Demodulation ◽

Symbol Detection ◽

Detection Software ◽

Threshold Problem ◽

Demodulation Method

PCM/FM system is one of the most widely used in the rocket telemetry system. Target spacecraft reentry telemetry telemetry signals in the process of low signal noise ratio (SNR), that the breakthrough tradition demodulation method of demodulation threshold problem, combined with the PCM/FM signal phase characteristic, the research based on a baseband complex rotating orthogonal symbol detection software (MSD) to solve method, and the corresponding synchronization algorithm is applied to ensure the smooth operation of the demodulation. The simulation and test results verified the soft demodulation algorithm can make the demodulation threshold effectively reduce.

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Research on Software Demodulation of PCM/FM Algorithm Based on MSD

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.989-994.2727 ◽

2014 ◽

Vol 989-994 ◽

pp. 2727-2730

Author(s):

Gang Fu ◽

Yan Jun Wu ◽

Ren Long Li ◽

Li Ping Wang

Keyword(s):

Maximum Likelihood ◽

Basic Principle ◽

Implementation Process ◽

Soft Demodulation ◽

Symbol Detection ◽

Demodulation Method

Based on maximum likelihood, research a new based on Symbol Detection (Multi-Symbol Detection, MSD) soft demodulation method of PCM/FM telemetry signals. Introduced the basic principle of the demodulation method and the implementation process, analyzed the demodulation and synchronization factors and formulate the corresponding synchronization strategies.

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A Clock Soft Synchronization Method Based on CAN Bus and Synchronization Error Analysis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.542-543.699 ◽

2012 ◽

Vol 542-543 ◽

pp. 699-704

Author(s):

Ji Jiao ◽

Fei Fan Chen

Keyword(s):

Control System ◽

Can Bus ◽

Propagation Delay ◽

Synchronization Error ◽

Measurement And Control System ◽

Synchronization Method ◽

Transmission Distance ◽

Distributed Measurement ◽

And Control ◽

Measurement And Control

Based on information pipeline technology, a clock soft synchronization method used in distributed measurement and control system is proposed. Using a separate information pipeline, the synchronization information is broadcasted to nodes in the distributed measurement and control system by synchronization node every message transaction cycle time, and all nodes automatically synchronize the local clock after receiving it. We analyze the theoretical synchronization error and verify this clock soft synchronization method in CAN bus. The theory analysis and experimental results indicate that the synchronization error mainly consists of propagation delay error, drift error and CAN loop delay error, and it increases linearly with the increasing of transmission distance.

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