Five-electrode configurations were designed to simulate the distribution inhomogeneity of electric field intensities in the air-insulating medium, and the characteristic data waveforms of partial discharge generated b...Five-electrode configurations were designed to simulate the distribution inhomogeneity of electric field intensities in the air-insulating medium, and the characteristic data waveforms of partial discharge generated by different electrode configurations under the excitation of power frequency AC voltage were carefully collected in this paper. Furthermore, the feature vectors of the corresponding fingerprint, contained in partial discharge data, were extracted by rigorous mathematical algorithms, and the artificial neural network was employed to realize the pattern recognition of partial discharge caused by the inhomogeneity of electric field intensity with different electrode configurations. The results indicate that the J<sub>4</sub> value in the space of 7 feature quantities is 1905.6, and the recognition rate is 100% when the hidden layer neuron of the network is 19. However, the J<sub>5</sub> value of 9 feature quantities is 1589.9, and the purpose of recognition has been achieved when the number of hidden layer neurons of the network is 6. Increasing the number of hidden layer neurons will only waste computing resources. Of course, PD information collection mode, feature quantity selection, optimal feature space composition, network structure and classification algorithm are the key to realizing PD fault intelligence identification.展开更多
为了提高水声通信的性能,提出了一种联合运用 M 元扩频(MSS)通信和 Pattern时延差编码(PDS)水声通信体制,并采用单阵元被动式时间反转镜(PTRM)来实现声信道均衡的深海远程水声通信方案。该方案的 M 元扩频-Pattern 时延差编码通信技术...为了提高水声通信的性能,提出了一种联合运用 M 元扩频(MSS)通信和 Pattern时延差编码(PDS)水声通信体制,并采用单阵元被动式时间反转镜(PTRM)来实现声信道均衡的深海远程水声通信方案。该方案的 M 元扩频-Pattern 时延差编码通信技术既能胜任远程水声通信,又能提高通信速率;单阵元被动式时间反转镜信道均衡技术既可抑制多途扩展产生的码间干扰,又能提高信噪比。根据深海声道特性分析,该方案将通信固定节点置于声道轴以获取会聚增益,提高通信距离。计算机仿真结果证明,所提出的深海远程水声通信方案具有很好的鲁棒性和可行性。展开更多
Underwater acoustic communication based on Pattern Tune Delay Shift Coding （PDS） communication scheme is studied. The time delay shift values of the pattern are used to encode the digital information in the PDS sche...Underwater acoustic communication based on Pattern Tune Delay Shift Coding （PDS） communication scheme is studied. The time delay shift values of the pattern are used to encode the digital information in the PDS scheme, which belongs to the Pulse Position Modulation （PPM）. The duty cycle of the PDS scheme is small, so it can economize the power for communication. By use of different patterns for code division and different frequencies for channel division, the communication system is capable of mitigating the inter-symbol interference （ISI） caused by the muhipath channel. The data rate of communication is 1000 bits/s at 8 kHz bandwidth. The receiver separates the channels by means of bandpass filters, and performs decoding by 4 copy-correlators to estimate the time delay shift value. Based on the theoretical analysis and numerical simulations, the PDS scheme is shown to be a robust and effective approach for underwater acoustic communication.展开更多
Pattern时延差编码(PDS:Pattern time Delay Shift coding)水声通信体制能有效地抑制水声通信中多途扩展引起的信号波形畸变对通信性能的影响,而RS码具有与PDS通信体制结合的先天优越性。为进一步降低水声通信系统的误比特率,提出将RS码...Pattern时延差编码(PDS:Pattern time Delay Shift coding)水声通信体制能有效地抑制水声通信中多途扩展引起的信号波形畸变对通信性能的影响,而RS码具有与PDS通信体制结合的先天优越性。为进一步降低水声通信系统的误比特率,提出将RS码与PDS通信体制结合,并对RS码在PDS水声通信体制中的性能进行研究。对挑选的RS码与常用的卷积码在PDS通信体制中的性能进行了仿真对比。结果表明,RS码在PDS通信体制中的性能远优于卷积码,对系统性能有明显提高。展开更多
文摘Five-electrode configurations were designed to simulate the distribution inhomogeneity of electric field intensities in the air-insulating medium, and the characteristic data waveforms of partial discharge generated by different electrode configurations under the excitation of power frequency AC voltage were carefully collected in this paper. Furthermore, the feature vectors of the corresponding fingerprint, contained in partial discharge data, were extracted by rigorous mathematical algorithms, and the artificial neural network was employed to realize the pattern recognition of partial discharge caused by the inhomogeneity of electric field intensity with different electrode configurations. The results indicate that the J<sub>4</sub> value in the space of 7 feature quantities is 1905.6, and the recognition rate is 100% when the hidden layer neuron of the network is 19. However, the J<sub>5</sub> value of 9 feature quantities is 1589.9, and the purpose of recognition has been achieved when the number of hidden layer neurons of the network is 6. Increasing the number of hidden layer neurons will only waste computing resources. Of course, PD information collection mode, feature quantity selection, optimal feature space composition, network structure and classification algorithm are the key to realizing PD fault intelligence identification.
文摘为了提高水声通信的性能,提出了一种联合运用 M 元扩频(MSS)通信和 Pattern时延差编码(PDS)水声通信体制,并采用单阵元被动式时间反转镜(PTRM)来实现声信道均衡的深海远程水声通信方案。该方案的 M 元扩频-Pattern 时延差编码通信技术既能胜任远程水声通信,又能提高通信速率;单阵元被动式时间反转镜信道均衡技术既可抑制多途扩展产生的码间干扰,又能提高信噪比。根据深海声道特性分析,该方案将通信固定节点置于声道轴以获取会聚增益,提高通信距离。计算机仿真结果证明,所提出的深海远程水声通信方案具有很好的鲁棒性和可行性。
文摘Underwater acoustic communication based on Pattern Tune Delay Shift Coding （PDS） communication scheme is studied. The time delay shift values of the pattern are used to encode the digital information in the PDS scheme, which belongs to the Pulse Position Modulation （PPM）. The duty cycle of the PDS scheme is small, so it can economize the power for communication. By use of different patterns for code division and different frequencies for channel division, the communication system is capable of mitigating the inter-symbol interference （ISI） caused by the muhipath channel. The data rate of communication is 1000 bits/s at 8 kHz bandwidth. The receiver separates the channels by means of bandpass filters, and performs decoding by 4 copy-correlators to estimate the time delay shift value. Based on the theoretical analysis and numerical simulations, the PDS scheme is shown to be a robust and effective approach for underwater acoustic communication.
文摘Pattern时延差编码(PDS:Pattern time Delay Shift coding)水声通信体制能有效地抑制水声通信中多途扩展引起的信号波形畸变对通信性能的影响,而RS码具有与PDS通信体制结合的先天优越性。为进一步降低水声通信系统的误比特率,提出将RS码与PDS通信体制结合,并对RS码在PDS水声通信体制中的性能进行研究。对挑选的RS码与常用的卷积码在PDS通信体制中的性能进行了仿真对比。结果表明,RS码在PDS通信体制中的性能远优于卷积码,对系统性能有明显提高。
