scholarly journals Research on Electromagnetic Detection Emission System for Spread Spectrum Code

2018 ◽  
Author(s):  
Shiqiang Li ◽  
Guoqiang Liu ◽  
Yaning Han ◽  
Yanhong Li ◽  
Xing Xu
Keyword(s):  
Spread Spectrum ◽  
Electromagnetic Detection ◽  
Emission System

Research on the Waveform Synthesis of Electromagnetic Detection Inverter Based on FPGA

2012 ◽  
Vol 433-440 ◽  
pp. 5628-5635
Author(s):  
Shi Qiang Li ◽  
Guo Qiang Liu ◽  
Hui Xia ◽  
Yan Hong Li
Keyword(s):  
Electromagnetic Emission ◽  
Detection Accuracy ◽  
Load Range ◽  
Positive Role ◽  
Electromagnetic Detection ◽  
Geological Conditions ◽  
Waveform Synthesis ◽  
Emission System ◽  
Multiple Frequencies ◽  
Control Circuits

Complex geological conditions and limited launch frequencies are the problems which the geological electromagnetic detection faced in our country. In this paper, we designed two FPGA-based detection of electromagnetic emission source inverter control circuits, one is using a phase-shift and complementary drive signal to expand the load range of electromagnetic emission system; the other one is using waveform synthesis technology to achieve that multiple frequencies could launch at one-time, and this method improves the detection accuracy. Both the two control circuits have a positive role in promoting the performance of electromagnetic detection equipment the development of Geological Survey in China.

A Field Emission System For Transmission Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 298-299
Author(s):  
Michel Troyonal ◽  
Huei Pei Kuoal ◽  
Benjamin M. Siegelal
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Optical System ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Objective Lens ◽  
Electron Optical System ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Emission System

A field emission system for our experimental ultra high vacuum electron microscope has been designed, constructed and tested. The electron optical system is based on the prototype whose performance has already been reported. A cross-sectional schematic illustrating the field emission source, preaccelerator lens and accelerator is given in Fig. 1. This field emission system is designed to be used with an electron microscope operated at 100-150kV in the conventional transmission mode. The electron optical system used to control the imaging of the field emission beam on the specimen consists of a weak condenser lens and the pre-field of a strong objective lens. The pre-accelerator lens is an einzel lens and is operated together with the accelerator in the constant angular magnification mode (CAM).

Analisis Karakterisasi Teknologi Direct Sequence Spread Spectrum Dan Frequency Hopping Spread Spectrum

2019 ◽  
Vol 2 (2) ◽  
pp. 129-138
Author(s):  
Fawzan Galib Abdul Karim Bawahab ◽  
Elvan Yuniarti ◽  
Edi Kurniawan
Keyword(s):  
Spread Spectrum ◽  
Communication Systems ◽  
Multiple Access ◽  
Frequency Hopping ◽  
Direct Sequence Spread Spectrum ◽  
Direct Sequence ◽  
Frequency Hopping Spread Spectrum ◽  
Two Systems ◽  
The Difference

Abstrak. Pada penelitian ini, telah dilakukan analisa karakterisasi pada teknologi Direct Sequence Spread Spectrum dan Frequency Hopping Spread Spectrum, sebagai salah satu teknik multiple-access pada sistem komunikasi. Karakterisasi dilakukan untuk mencari bagaimana cara meningkatkan keoptimalan kedua sistem tersebut, dalam mengatasi masalah interferensi dengan sistem dan channel yang sama. Dan juga untuk menentukan veriabel apa yang mempengaruhi keoptimalan kedua sistem tersebut. Karakterisasi dilakukan dengan menentukan variabel-variabel yang mempengaruhi keoptimalan keduanya. Hasil dari karakterisasi, diketahui variabel-variabel yang mempengaruhi kemampuan sistem DSSS yaitu nilai frekuensi spreading (). Sedangkan untuk sistem FHSS yaitu nilai frekuensi spreading ( dan ) dan selisih antara frekuensi hopping data dengan frekuensi hopping interferensi . Kata Kunci: BER, DSSS, FHSS, Interference, Spread spectrum. Abstract. In this study, characterization of Direct Sequence Spread Spectrum and Frequency Hopping Spread Spectrum technologies have been done, as one of the multiple-access techniques in communication systems. Characterization is done to find out how to improve the ability of the two systems, in solving interference problems with the same system and channel. And also to determine what veriabel affects the ability of the two systems. Characterization is done by determining the variables that affect the ability of both. The results of the characterization, known variables that affect the ability of the DSSS system are the spreading frequency value (). As for the FHSS system, the spreading frequency value ( and ) and the difference between frequency hopping data with frequency hopping interference .

Field tests of a spread spectrum land mobile satellite communicationsystem using ETS-V satellite

1992 ◽  
Author(s):  
TETSUSHI IKEGAMI ◽  
SHINICHI TAIRA ◽  
YOSHIYA ARAKAKI ◽  
RYUTARO SUZUKI
Keyword(s):  
Spread Spectrum ◽  
Field Tests ◽  
Mobile Satellite

SIMULATION OF DIRECT SPREAD SPECTRUM COMMUNICATION SYSTEM ON THE HARDWARE MODULE EMONA DATEX. EVALUATION OF THE EFFECT OF NOISE ON THE QUALITY OF DEMODULATION

2019 ◽  
Author(s):  
Maksim Zhmakin ◽  
Irina Chadyuk ◽  
Aleksey Nadymov
Keyword(s):  
Spread Spectrum ◽  
Communication System ◽  
Spread Spectrum Communication ◽  
Direct Spread ◽  
Simulation Results

A variant of implementation of a communication system with direct spread spectrum is presented in this article, simulation results are also presented, the main parameters of the system are taken, and conclusions are drawn.

Sign in / Sign up

Export Citation Format

Share Document