Partial discharge measurement is one of the most effective methods to find insulation defects and early failure of high voltage power equipments. The accuracy is significantly reduced by the interference in the partia...Partial discharge measurement is one of the most effective methods to find insulation defects and early failure of high voltage power equipments. The accuracy is significantly reduced by the interference in the partial discharge on-site detection or on-line monitoring, especially by the pulse interference. This paper studies the phase correlation of some types of typical partial discharge pulses and their characteristics in time domain and frequency domain. By collecting enough partial discharge pulse data, the correlation coefficient can be calculated based on both phase correlation and waveform similarity. The type of pulse will be determined by the scope of the calculated correlation coefficient. The pulses with very strong correlation will be identified as periodic pulse interference. The pulses with very weak correlation will be identified as random pulse interference. Only the pulses whose correlation coefficients fall into a specific range will be identified as partial discharge signals. In laboratory, simulated pulse interference is injected into measurement circuit, and typical partial discharge pulses are sampled by a high-speed acquisition system. The pulse interference can be effectively separated from partial discharge signals by correlation coefficient.展开更多
A Mixed Numerology OFDM(MN-OFDM)system is essential in 6G and beyond.However,it encounters challenges due to Inter-Numerology Interference(INI).The upcoming 6G technology aims to support innovative applications with h...A Mixed Numerology OFDM(MN-OFDM)system is essential in 6G and beyond.However,it encounters challenges due to Inter-Numerology Interference(INI).The upcoming 6G technology aims to support innovative applications with high data rates,low latency,and reliability.Therefore,effective handling of INI is crucial to meet the diverse requirements of these applications.To address INI in MN-OFDM systems,this paper proposes a User-Based Numerology and Waveform(UBNW)approach that uses various OFDM-based waveforms and their parameters to mitigate INI.By assigning a specific waveform and numerology to each user,UBNW mitigates INI,optimizes service characteristics,and addresses user demands efficiently.The required Guard Bands(GB),expressed as a ratio of user bandwidth,vary significantly across different waveforms at an SIR of 25 dB.For instance,OFDM-FOFDM needs only 2.5%,while OFDM-UFMC,OFDM-WOLA,and conventional OFDM require 7.5%,24%,and 40%,respectively.The time-frequency efficiency also varies between the waveforms.FOFDM achieves 85.6%,UFMC achieves 81.6%,WOLA achieves 70.7%,and conventional OFDM achieves 66.8%.The simulation results demonstrate that the UBNW approach not only effectively mitigates INI but also enhances system flexibility and time-frequency efficiency while simultaneously reducing the required GB.展开更多
The ability to modulate an optical field via an electric field is regarded as a key function of electro-optic interconnects, which are used in optical communications and information-processing systems. One of the main...The ability to modulate an optical field via an electric field is regarded as a key function of electro-optic interconnects, which are used in optical communications and information-processing systems. One of the main devices required for such interconnects is the electro-optic modulator(EOM). Current EOMs based on electro-optic and electro-absorption effects often are bulky and power-inefficient due to the weak electro-optic properties of their constituent materials. Here, we propose a new mechanism to produce an arbitrary-waveform EOM based on quantum interference, in which both real and imaginary parts of the susceptibility are engineered coherently with super-high efficiency. Based on this EOM, a waveform interconnect from the voltage to the modulated optical absorption is realized. We expect that such a new type of electro-optic interconnect will have a broadrange of applications, including in optical communications and networks.展开更多
文摘Partial discharge measurement is one of the most effective methods to find insulation defects and early failure of high voltage power equipments. The accuracy is significantly reduced by the interference in the partial discharge on-site detection or on-line monitoring, especially by the pulse interference. This paper studies the phase correlation of some types of typical partial discharge pulses and their characteristics in time domain and frequency domain. By collecting enough partial discharge pulse data, the correlation coefficient can be calculated based on both phase correlation and waveform similarity. The type of pulse will be determined by the scope of the calculated correlation coefficient. The pulses with very strong correlation will be identified as periodic pulse interference. The pulses with very weak correlation will be identified as random pulse interference. Only the pulses whose correlation coefficients fall into a specific range will be identified as partial discharge signals. In laboratory, simulated pulse interference is injected into measurement circuit, and typical partial discharge pulses are sampled by a high-speed acquisition system. The pulse interference can be effectively separated from partial discharge signals by correlation coefficient.
基金supported by National Natural Science Foundation of China(No.U1533107)Key Program of Tianjin Natural Science Foundation(No.17JCZDJC30900)+1 种基金the Fundamental Research Funds for the Central Universities of CAUC(No.3122016D003)the Graduate Program of Curriculum Development Project of Civil Aviation University of China(No.2050070515)
文摘A Mixed Numerology OFDM(MN-OFDM)system is essential in 6G and beyond.However,it encounters challenges due to Inter-Numerology Interference(INI).The upcoming 6G technology aims to support innovative applications with high data rates,low latency,and reliability.Therefore,effective handling of INI is crucial to meet the diverse requirements of these applications.To address INI in MN-OFDM systems,this paper proposes a User-Based Numerology and Waveform(UBNW)approach that uses various OFDM-based waveforms and their parameters to mitigate INI.By assigning a specific waveform and numerology to each user,UBNW mitigates INI,optimizes service characteristics,and addresses user demands efficiently.The required Guard Bands(GB),expressed as a ratio of user bandwidth,vary significantly across different waveforms at an SIR of 25 dB.For instance,OFDM-FOFDM needs only 2.5%,while OFDM-UFMC,OFDM-WOLA,and conventional OFDM require 7.5%,24%,and 40%,respectively.The time-frequency efficiency also varies between the waveforms.FOFDM achieves 85.6%,UFMC achieves 81.6%,WOLA achieves 70.7%,and conventional OFDM achieves 66.8%.The simulation results demonstrate that the UBNW approach not only effectively mitigates INI but also enhances system flexibility and time-frequency efficiency while simultaneously reducing the required GB.
基金National Natural Science Foundation of China(NSFC)(11505100,11547035,11575071,11604147,11674337,61605225,91321101)Natural Science Foundation of Shanghai(16ZR1448400)+2 种基金Natural Science Foundation of Shandong Province(ZR2015AQ007)Strategic Priority Research Program(XDB01010200)Hundred Talents Program of the Chinese Academy of Sciences(CAS)(Y321311401)
文摘The ability to modulate an optical field via an electric field is regarded as a key function of electro-optic interconnects, which are used in optical communications and information-processing systems. One of the main devices required for such interconnects is the electro-optic modulator(EOM). Current EOMs based on electro-optic and electro-absorption effects often are bulky and power-inefficient due to the weak electro-optic properties of their constituent materials. Here, we propose a new mechanism to produce an arbitrary-waveform EOM based on quantum interference, in which both real and imaginary parts of the susceptibility are engineered coherently with super-high efficiency. Based on this EOM, a waveform interconnect from the voltage to the modulated optical absorption is realized. We expect that such a new type of electro-optic interconnect will have a broadrange of applications, including in optical communications and networks.
