Analysis on the amplitude instability of homodyne coherent demodulation method based on a 3×3 coupler for fiber laser hydrophone

2011 ◽  
Author(s):  
Jun-bin Huang ◽  
Yu Li ◽  
Hong-can Gu ◽  
Ri-zhong Li ◽  
Bo Tan ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Coherent Demodulation ◽  
Demodulation Method

Research on FM Telemetry Software Demodulation Algorithms

2014 ◽  
Vol 989-994 ◽  
pp. 3938-3941
Author(s):  
Gang Fu ◽  
Yan Jun Wu ◽  
Ren Long Li ◽  
Li Ping Wang
Keyword(s):  
Maximum Likelihood ◽  
Decision Process ◽  
Present Situation ◽  
Telemetry System ◽  
Coherent Demodulation ◽  
Synchronization Method ◽  
Symbol Detection ◽  
And Control ◽  
Measurement And Control ◽  
Demodulation Method

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.

scholarly journals Resolution-Enhancing Structure for the Electric Field Microsensor Chip

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 936
Author(s):  
Xiaolong Wen ◽  
Pengfei Yang ◽  
Zhouwei Zhang ◽  
Zhaozhi Chu ◽  
Chunrong Peng ◽  
...  
Keyword(s):  
Electric Field ◽  
Metal Plate ◽  
Measuring Error ◽  
Production Lines ◽  
Capacitance Sensor ◽  
Coherent Demodulation ◽  
Ansys Simulation ◽  
Static Monitoring ◽  
Demodulation Method ◽  
Magnification Effect

Electrostatic voltage is a vital parameter in industrial production lines, for reducing electrostatic discharge harms and improving yields. Due to such drawbacks as package shielding and low resolution, previously reported electric field microsensors are still not applicable for industrial static monitoring uses. In this paper, we introduce a newly designed microsensor package structure, which enhances the field strength inside the package cavity remarkably. This magnification effect was studied and optimized by both theoretical calculation and ANSYS simulation. By means of the digital synthesizer and digital coherent demodulation method, the compact signal processing circuit for the packaged microsensor was also developed. The meter prototype was calibrated above a charged metal plate, and the electric field resolution was 5 V/m, while the measuring error was less than 3 V, from −1 kV to 1 kV in a 2 cm distance. The meter was also installed into a production line and showed good consistency with, and better resolution than, a traditional vibratory capacitance sensor.

Demodulating Method of Frequency Predictable Digital FM Signal

2014 ◽  
Vol 644-650 ◽  
pp. 4595-4598
Author(s):  
Gang Fu ◽  
Jian Hua Lin ◽  
Qian He
Keyword(s):  
Background Noise ◽  
Noise Immunity ◽  
Estimation Method ◽  
New Method ◽  
Signal Estimation ◽  
Signal Phase ◽  
Frequency Signal ◽  
Phase Fluctuations ◽  
Coherent Demodulation ◽  
Demodulation Method

This paper presents a new method for strong background noise of known frequency signal estimation method is then applied to the demodulated digital FM signal. This new method only needs to know the frequency of the demodulated carrier signal phase information without the need to complete the digital FM demodulation signal. Computer simulations show that the method has more than non-coherent demodulation noise immunity, and has a very strong ability of anti-phase fluctuations. Thus, the demodulation method has good prospects for engineering applications.

Distributed Feedback Fiber Laser Rosette for Acoustic Emission Detection

2013 ◽  
Vol 330 ◽  
pp. 412-417 ◽  
Author(s):  
Wen Zhu Huang ◽  
Wen Tao Zhang ◽  
Huai Xiang Ma ◽  
Fang Li ◽  
Yan Liang Du
Keyword(s):  
Acoustic Emission ◽  
Fiber Laser ◽  
Health Monitoring ◽  
Fiber Optic ◽  
Practical Method ◽  
Distributed Feedback ◽  
Large Structure ◽  
Narrow Line Width ◽  
Emission Detection ◽  
Demodulation Method

This study aims at providing a practical method in large structure health monitoring. A novel fiber optic rosette based on distributed feedback (DFB) fiber laser for acoustic emission (AE) detection and location is presented. The ultra-narrow line width of the DFB fiber laser will result in high resolution in AE wave detection using a fiber optic interferometric demodulation method. The directivity of the fiber optic rosette is investigated. A rosette with three DFB fiber lasers is tested in the experiment to determine the direction of propagation of AE waves.

Analysis on Anti-Noise Performance of Frequency Modulation System Based on MATLAB Simulation

2014 ◽  
Vol 543-547 ◽  
pp. 2426-2430
Author(s):  
Zhang Cheng Yang ◽  
Xiang Lin Wang
Keyword(s):  
Frequency Modulation ◽  
Internet Technology ◽  
Network Communication ◽  
Noise Performance ◽  
Matlab Simulation ◽  
Technology Application ◽  
Coherent Demodulation ◽  
Modulation And Demodulation ◽  
Communication Signal ◽  
Demodulation Method

The popularity of internet technology has brought the change very big to the life and production of modern humans, the current Internet technology application has penetrated into people in every aspect of modern life, has become an indispensable part of people's life. Firstly, system model of the current network communication to dissect, analyzes the architecture of network communication system, modulation and demodulation principle is applied to design the FM communication signal modulation system network communication in the Internet technology, the non coherent demodulation method to build FM demodulation system, realize the demodulation process through differential device, the anti noise performance of the method of frequency modulation system of MATLAB simulation experiments, the experimental results show that the method of anti noise performance significantly, to a certain extent, provide theoretical basis and technical support for the research in this field.

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