Measurement system of shipboard indoor signal propagation characteristics based on three way signature sequence packet mode

Author(s):  
Jeong-Ho Kim ◽  
Ji-Hyun Moon ◽  
Na-Hyung Kim
2019 ◽  
Vol 102 (5) ◽  
pp. 27-34
Author(s):  
Yuya Kobayashi ◽  
Akihiko Akao ◽  
Sho Shirasaka ◽  
Kiyoshi Kotani ◽  
Yasuhiko Jimbo

2019 ◽  
Vol 283 ◽  
pp. 02003
Author(s):  
Jun Zhu ◽  
Hanhao Zhu ◽  
Jun Tang ◽  
Guangxue Zheng

Targeted at the issue of extremely low-frequency (<100Hz) acoustic propagation in complex shallow elastic bottom environments. The influence law of different complex elastic bottoms on the acoustic signal propagation at very low frequency by acoustic energy flux has been analyzed with the simulation, which is based on the finite element method. The elastic bottoms which have been studied are the shallow horizontal elastic bottom, and the up-sloping and the down-sloping elastic bottom. The results show that the acoustic signal propagating in the up-sloping and down-sloping elastic bottom environments is more complex than that propagating in the horizontal elastic bottom, and the acoustic energy leaking into those elastic bottoms has very different influence on the acoustic signal propagation, especially in the up-sloping bottom.


2013 ◽  
Vol 385-386 ◽  
pp. 1568-1571
Author(s):  
Yi Dong Xu

It's one of the effective channels for short-distance wireless communications through stratum in underground mines on emergency communications. The geologic structure is complex in mines, in practical environments. It means there is a considerable difference in conductance property and channel characteristics. In order to realize effective communication through stratum, its necessary to explore and study underground signal transmission by establishing mathematical model of underground signal propagation characteristics based on the theory of constant current field and simulating the mathematical model with MATLAB. We established a simulation model of underground communication channel physics experiments and obtained the amplitude frequency characteristic of the channel, with which we can get the error comparison between theory and test.


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