Achieving reliable underwater communication in shallow water acoustic channels is a difficult task because of the random time varying nature of multipath propagation, severe amplitude fluctuation, and spatial variabil...Achieving reliable underwater communication in shallow water acoustic channels is a difficult task because of the random time varying nature of multipath propagation, severe amplitude fluctuation, and spatial variability of the channel conditions. This paper describes a new signal processing technique frequency coding and decoding by means of real time measurement of signal width, jamming and suppressing multipath interference and using redundant coder. The application of the technique to the model ZTY 1 status monitor for underwater system of seabed is introduced in this paper. The main principle, the technique specifications and the key techniques of the system are discussed here. Theoretical estimations and experimental results proved that the performance of the system is excellent. The method can be used for some other related low data rate data transmission detecting in shallow water acoustic channel.展开更多
Reliability and anti-interference ability are the two most important factors in the normal operation of instruments, and even determine the precise effect of instruments in production and processing. Especially with t...Reliability and anti-interference ability are the two most important factors in the normal operation of instruments, and even determine the precise effect of instruments in production and processing. Especially with the expansion of the application scope of instruments and the improvement of the technical content in recent years, its use conditions and environment are becoming increasingly strict. Therefore, it is very important to improve the reliability and anti-interference ability of instruments.展开更多
In recent years, microelectronic components are more widely used in relay protection devices, but most of the electronic devices are electronic sensitive devices, which are easy to be affected by interference. When th...In recent years, microelectronic components are more widely used in relay protection devices, but most of the electronic devices are electronic sensitive devices, which are easy to be affected by interference. When the relay protection devices are interfered in the power system, if there is a fault, it will affect the overall security of the power grid, resulting in the power grid cannot operate stably. When the interference energy exceeds the maximum allowable energy of the logic circuit, it will directly damage the components and affect the normal operation of the relay protection device. Therefore, strengthening the anti-interference ability of relay protection and automation devices has become an important topic in power system.展开更多
Due to the outstanding anti-interference capability against the ambient noise,LiDARs based on frequencymodulated continuous wave(FMCW)technology with high sensitivity and high signal-to-noise ratio(SNR)are essential t...Due to the outstanding anti-interference capability against the ambient noise,LiDARs based on frequencymodulated continuous wave(FMCW)technology with high sensitivity and high signal-to-noise ratio(SNR)are essential to achieve ideal photodetection of weak light.To significantly improve the weak light detection performance of balanced photodetectors,this work first demonstrates a novel near-infrared germanium-on-silicon(Ge/Si)avalanche photodetector with a three-electrode balanced scheme.The single three-electrode avalanche photodetector exhibits a high responsivity of>200 A=W near breakdown voltage.The three-electrode balanced avalanche photodetector(3ele-BAPD)achieves a common-mode rejection ratio(CMRR)of 50 dB at an operating wavelength of 1550 nm.We have set up the FMCW coherent detection system.The minimum detectable power of−93 dBm can be achieved,corresponding to an SNR of 3.2 dB and a detection probability of 54%.In comparison,the performance exceeds that of the two-electrode balanced avalanche photodetector(2ele-BAPD),which exhibits a minimum detectable power of−85 dBm with a corresponding SNR of 3.1 dB and a detection probability of 51%.The superior weak light detection performance enables the 3ele-BAPD to accomplish 3D imaging based on the FMCW LiDAR scheme.Moreover,the 3ele-BAPD is also applied to velocity measurement for 4D sensing.The applications of LiDAR velocity measurement and imaging are verified.展开更多
文摘Achieving reliable underwater communication in shallow water acoustic channels is a difficult task because of the random time varying nature of multipath propagation, severe amplitude fluctuation, and spatial variability of the channel conditions. This paper describes a new signal processing technique frequency coding and decoding by means of real time measurement of signal width, jamming and suppressing multipath interference and using redundant coder. The application of the technique to the model ZTY 1 status monitor for underwater system of seabed is introduced in this paper. The main principle, the technique specifications and the key techniques of the system are discussed here. Theoretical estimations and experimental results proved that the performance of the system is excellent. The method can be used for some other related low data rate data transmission detecting in shallow water acoustic channel.
文摘Reliability and anti-interference ability are the two most important factors in the normal operation of instruments, and even determine the precise effect of instruments in production and processing. Especially with the expansion of the application scope of instruments and the improvement of the technical content in recent years, its use conditions and environment are becoming increasingly strict. Therefore, it is very important to improve the reliability and anti-interference ability of instruments.
文摘In recent years, microelectronic components are more widely used in relay protection devices, but most of the electronic devices are electronic sensitive devices, which are easy to be affected by interference. When the relay protection devices are interfered in the power system, if there is a fault, it will affect the overall security of the power grid, resulting in the power grid cannot operate stably. When the interference energy exceeds the maximum allowable energy of the logic circuit, it will directly damage the components and affect the normal operation of the relay protection device. Therefore, strengthening the anti-interference ability of relay protection and automation devices has become an important topic in power system.
基金National Natural Science Foundation of China(62090054,61934003)National Key Research and Development Program of China(2022YFB2804504)+2 种基金Major Scientific and Technological Program of Jilin Province(20210301014GX)Jilin Provincial Development and Reform Commission Project(2020C056)Program for Jilin University Science and Technology Innovative Research Team(JLUSTIRT,2021TD-39).
文摘Due to the outstanding anti-interference capability against the ambient noise,LiDARs based on frequencymodulated continuous wave(FMCW)technology with high sensitivity and high signal-to-noise ratio(SNR)are essential to achieve ideal photodetection of weak light.To significantly improve the weak light detection performance of balanced photodetectors,this work first demonstrates a novel near-infrared germanium-on-silicon(Ge/Si)avalanche photodetector with a three-electrode balanced scheme.The single three-electrode avalanche photodetector exhibits a high responsivity of>200 A=W near breakdown voltage.The three-electrode balanced avalanche photodetector(3ele-BAPD)achieves a common-mode rejection ratio(CMRR)of 50 dB at an operating wavelength of 1550 nm.We have set up the FMCW coherent detection system.The minimum detectable power of−93 dBm can be achieved,corresponding to an SNR of 3.2 dB and a detection probability of 54%.In comparison,the performance exceeds that of the two-electrode balanced avalanche photodetector(2ele-BAPD),which exhibits a minimum detectable power of−85 dBm with a corresponding SNR of 3.1 dB and a detection probability of 51%.The superior weak light detection performance enables the 3ele-BAPD to accomplish 3D imaging based on the FMCW LiDAR scheme.Moreover,the 3ele-BAPD is also applied to velocity measurement for 4D sensing.The applications of LiDAR velocity measurement and imaging are verified.
