scholarly journals Active underwater acoustic control of polymer based piezoelectric composites

2021 ◽  
Vol 2009 (1) ◽  
pp. 012064
Author(s):  
Zou Simin
Keyword(s):  
Piezoelectric Composites ◽  
Underwater Acoustic ◽  
Acoustic Control

FH-FSK Underwater Acoustic Control and Communication System Based on LDPC Code

2014 ◽  
Vol 511-512 ◽  
pp. 375-380
Author(s):  
Ji Gang Dong ◽  
Da Jun Sun ◽  
You Wen Zhang ◽  
Wei Wei Fan
Keyword(s):  
Communication System ◽  
Convolutional Code ◽  
Gaussian White Noise ◽  
Ldpc Code ◽  
Parity Check ◽  
Underwater Acoustic ◽  
Low Density Parity Check ◽  
Acoustic Control ◽  
Shift Keying ◽  
Parity Check Codes

In this paper, a frequency-hopping frequency-shift keying (FH-FSK) underwater acoustic control and communication system based on Low Density Parity Check Codes (LDPC) is proposed by combining with FH-FSK system and LDPC. The anti-jamming performance of the system in the condition of Gaussian white noise and coherent multi-path channel is simulated respectively. The simulation result shows that FH-FSK system based on LDPC has a better performance than that of convolutional code. Therefore, it is more applicable for the system to have a stable anti-jamming performance and better robustness.

Piezocomposite actuator designs for an active underwater acoustic control system coating

1990 ◽  
Vol 87 (S1) ◽  
pp. S17-S17
Author(s):  
Thomas R. Howarth ◽  
Xiaoqi Bao ◽  
Vijay K. Varadan ◽  
Vasundara V. Varadan ◽  
Kim C. Benjamin
Keyword(s):  
Control System ◽  
Underwater Acoustic ◽  
Acoustic Control

scholarly journals 4D Printing of Lead Zirconate Titanate Piezoelectric Composites Transducer Based on Direct Ink Writing

2021 ◽  
Vol 8 ◽  
Author(s):  
Kai Liu ◽  
Qingqing Zhang ◽  
Chenyang Zhou ◽  
Yusheng Shi ◽  
Ce Sun ◽  
...  
Keyword(s):  
Lead Zirconate Titanate ◽  
Volume Fraction ◽  
Lead Zirconate ◽  
4D Printing ◽  
Piezoelectric Composites ◽  
Underwater Acoustic ◽  
Direct Ink Writing ◽  
Resin Impregnation ◽  
Zirconate Titanate ◽  
Acoustic Transducer

Lead zirconate titanate (PZT) piezoelectric composites used in transducers were fabricated via direct ink writing (DIW) combined with furnace sintering and resin impregnation. A ceramic slurry with a volume fraction of 52 vol% and suitable viscoelasticity was prepared. After post-process, the PZT ceramic specimens showed a nanoscale grain size with a density of 7.63 g/cm3, accounting for 97.8% of the theoretical density. The effects of different printing rod spacing on the electrical properties of composites were evaluated and lucubrated. Finally, an underwater acoustic transducer was assembled by using the PZT piezoelectric composites fabricated by the above method. The electrical signal generated by the underwater acoustic transducer changed autonomously with the acoustic stimulation, which indicated the application mode of 4D printing in functional devices in the future.

The Study and Implementation of the Anti-Doppler Technology of AUV Communication System

2014 ◽  
Vol 536-537 ◽  
pp. 999-1004
Author(s):  
Ji Gang Dong ◽  
Da Jun Sun ◽  
Wei Wei Fan
Keyword(s):  
Frequency Shift ◽  
Communication System ◽  
Doppler Frequency ◽  
Doppler Frequency Shift ◽  
Underwater Acoustic Communication ◽  
Underwater Acoustic ◽  
Acoustic Control ◽  
Shift Keying ◽  
Pair Method ◽  
On Chip

Due to the complexity of the underwater acoustic channel, a reliable mobile underwater acoustic communication system must have high resistance to Doppler and multi-path extension. In this paper, an AUV underwater acoustic control and communication system based on frequency-hopping frequency-shift keying (FH-FSK) is proposed. The system uses pulse pair method to estimate Doppler frequency shift, and analyzes the performance of the algorithm via simulation. The system has been developed based on chip OMAP-L138, with lake test conducted. Result of the tests shows that the system can estimate and compensate the Doppler frequency shift generated by the platform's movement precisely, and has strong resistance to interference to transmit AUV control messages effectively.

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