The spatial matrix filter was designed and used for solving the problem to detect a weak target who was influenced by the strong nearby platform noise interference of the towed line array sonar. The MFP technology and...The spatial matrix filter was designed and used for solving the problem to detect a weak target who was influenced by the strong nearby platform noise interference of the towed line array sonar. The MFP technology and the DOA estimation technology were combined together by using the sound propagation characteristics of both target and interference. The spatial matrix filter with platform noise zero response constraint was designed by the near-field platform noise normal modes copy vectors and the far-field plane wave bearing vectors together. The optimal solution of the optimization problem for designing the spatial matrix filter was deduced directly, and it was simplified by the generalized singular value decomposition. The total response error to the plane wave bearing vectors and the total response to the platform noise copy vectors were given. The phenomena that strong interferences existed in the bearing course and blind areas existed after filtering were analyzed by the correlation between the plat- form noise copy vectors and the plane wave bearing vectors. It could be found from simulations that it has less blind area and higher detection ability by using the spatial matrix filtering technology.展开更多
A program of adaptive quadrature demodulation is proposed to supply the gaps in the traditional analog detection technology of a silicon micro-machined gyroscope (SMG). This program is suitable for digital phase locke...A program of adaptive quadrature demodulation is proposed to supply the gaps in the traditional analog detection technology of a silicon micro-machined gyroscope (SMG). This program is suitable for digital phase locked loop (DPLL) drive technology that proposed in other papers. In addition the program adopts an adaptive filtering algorithm, which selects the in-phase and quadrature components that are outputs of the DPLL of the SMG's drive mode as reference signals to update the amplitude of the in-phase and quadrature components of the input signal by iteratively. An objective of the program is to minimize the mean square error of the accurate amplitudes and the estimated amplitudes of SMG's detection mode. The simulation and test results prove the feasibility of the program that lays the foundation for the further improvement of the SMG's system performance and the implementation of the SMG system's self-calibration and self-demarcation in future.展开更多
Signals from infrared detector are very weak in SO2 concentration measuring system.In order to improve the sensitivity of detection,combining with filter correlation technology and infrared absorption principle,the we...Signals from infrared detector are very weak in SO2 concentration measuring system.In order to improve the sensitivity of detection,combining with filter correlation technology and infrared absorption principle,the weak signal processing circuit is designed according to correlation detection technology.Under laboratory conditions,system performance of SO2 concentration is tested,and the experimental data are analyzed and processed.Then relationship of SO2 concentration and the measuring voltage is provided to prove that the design improves measuring sensitivity of the system.展开更多
WE43 alloy was successfully coated with ferrum(Fe)films of varying thicknesses using filtered cathode vacuum arc technology.The physical phase composition,surface morphology,corrosion resistance and mechanical propert...WE43 alloy was successfully coated with ferrum(Fe)films of varying thicknesses using filtered cathode vacuum arc technology.The physical phase composition,surface morphology,corrosion resistance and mechanical properties of the films were extensively investigated.The results demonstrate that a deposition time of 20 min for Fe ions exhibits minimal defects and low surface roughness.Compared to the WE43 substrate,the Fe20 alloy exhibits lower Icorr values at 81μA/cm^(2),indicating enhanced corrosion resistance.Immersion experiments further confirm the superior integrity of the Fe20 film compared to other coated alloys tested.Notably,among all deposited modified alloys,Fe20 demonstrates significantly improved mechanical properties with its hardness and elastic modulus being three times higher than those of WE43,providing better wear resistance.展开更多
As the core of marine communication,underwater acoustic communication technology significantly improves the performance of underwater communication by using technologies such as modulation,multiple access,and anti-int...As the core of marine communication,underwater acoustic communication technology significantly improves the performance of underwater communication by using technologies such as modulation,multiple access,and anti-interference.Among them,adaptive filtering technology plays a key role in eliminating noise and channel equalization.This paper explores the novel application of acoustic reconfigurable intelligence surface(ARIS)and adaptive filtering in underwater acoustic communication.We introduce the concept of ARIS assisted underwater acoustic communication,integrating the least mean squares(LMS)algorithm to dynamically estimate and mitigate oceanic noise.This approach further enhances signal clarity and communication quality by leveraging orthogonal frequency division multiplexing(OFDM)technology.Simulation results show that the underwater acoustic channel with ARIS is superior to the traditional channel without ARIS in terms of bit error rate and anti-interference performance.This technology significantly enhances the reception quality of underwater communication signals,making it suitable for applications in marine monitoring,military communication,and other complex environments.展开更多
A fourth-order Gm-C Chebyshev low-pass filter is presented as channel selection filter for reconfigurable multi-mode wireless receivers. Low-noise technologies are proposed in optimizing the noise characteristics of b...A fourth-order Gm-C Chebyshev low-pass filter is presented as channel selection filter for reconfigurable multi-mode wireless receivers. Low-noise technologies are proposed in optimizing the noise characteristics of both the Gm cells and the filter topology. A frequency tuning strategy is used by tuning both the transconductance of the Gm cells and the capacitance of the capacitor banks. To achieve accurate cut-off frequencies, an on-chip calibration circuit is presented to compensate for the frequency inaccuracy introduced by process variation. The filter is fabricated in a 0.13 m CMOS process. It exhibits a wide programmable bandwidth from 322.5 k Hz to20 MHz. Measured results show that the filter has low input referred noise of 5.9 n V/（Hz）^（1/2） and high out-of-band IIP3 of 16.2 d Bm. It consumes 4.2 and 9.5 m W from a 1 V power supply at its lowest and highest cut-off frequencies respectively.展开更多
基金supported by the National Natural Science Foundation of China(60532040,11374001)
文摘The spatial matrix filter was designed and used for solving the problem to detect a weak target who was influenced by the strong nearby platform noise interference of the towed line array sonar. The MFP technology and the DOA estimation technology were combined together by using the sound propagation characteristics of both target and interference. The spatial matrix filter with platform noise zero response constraint was designed by the near-field platform noise normal modes copy vectors and the far-field plane wave bearing vectors together. The optimal solution of the optimization problem for designing the spatial matrix filter was deduced directly, and it was simplified by the generalized singular value decomposition. The total response error to the plane wave bearing vectors and the total response to the platform noise copy vectors were given. The phenomena that strong interferences existed in the bearing course and blind areas existed after filtering were analyzed by the correlation between the plat- form noise copy vectors and the plane wave bearing vectors. It could be found from simulations that it has less blind area and higher detection ability by using the spatial matrix filtering technology.
文摘A program of adaptive quadrature demodulation is proposed to supply the gaps in the traditional analog detection technology of a silicon micro-machined gyroscope (SMG). This program is suitable for digital phase locked loop (DPLL) drive technology that proposed in other papers. In addition the program adopts an adaptive filtering algorithm, which selects the in-phase and quadrature components that are outputs of the DPLL of the SMG's drive mode as reference signals to update the amplitude of the in-phase and quadrature components of the input signal by iteratively. An objective of the program is to minimize the mean square error of the accurate amplitudes and the estimated amplitudes of SMG's detection mode. The simulation and test results prove the feasibility of the program that lays the foundation for the further improvement of the SMG's system performance and the implementation of the SMG system's self-calibration and self-demarcation in future.
文摘Signals from infrared detector are very weak in SO2 concentration measuring system.In order to improve the sensitivity of detection,combining with filter correlation technology and infrared absorption principle,the weak signal processing circuit is designed according to correlation detection technology.Under laboratory conditions,system performance of SO2 concentration is tested,and the experimental data are analyzed and processed.Then relationship of SO2 concentration and the measuring voltage is provided to prove that the design improves measuring sensitivity of the system.
基金Project supported by the National Natural Science Foundation of China(52271117)the Educational Commission of Hunan Province of China(23A0107)+1 种基金the High Technology Research and Development Program of Hunan Province of China(2022GK4038)the Research Development and Research Fund of Zhuhai People's Hospital(zh2017001)。
文摘WE43 alloy was successfully coated with ferrum(Fe)films of varying thicknesses using filtered cathode vacuum arc technology.The physical phase composition,surface morphology,corrosion resistance and mechanical properties of the films were extensively investigated.The results demonstrate that a deposition time of 20 min for Fe ions exhibits minimal defects and low surface roughness.Compared to the WE43 substrate,the Fe20 alloy exhibits lower Icorr values at 81μA/cm^(2),indicating enhanced corrosion resistance.Immersion experiments further confirm the superior integrity of the Fe20 film compared to other coated alloys tested.Notably,among all deposited modified alloys,Fe20 demonstrates significantly improved mechanical properties with its hardness and elastic modulus being three times higher than those of WE43,providing better wear resistance.
基金supported by the Open Fund Project of Key Laboratory of Ocean Observation Technology,Ministry of Natural Resources(No.2023klootA01).
文摘As the core of marine communication,underwater acoustic communication technology significantly improves the performance of underwater communication by using technologies such as modulation,multiple access,and anti-interference.Among them,adaptive filtering technology plays a key role in eliminating noise and channel equalization.This paper explores the novel application of acoustic reconfigurable intelligence surface(ARIS)and adaptive filtering in underwater acoustic communication.We introduce the concept of ARIS assisted underwater acoustic communication,integrating the least mean squares(LMS)algorithm to dynamically estimate and mitigate oceanic noise.This approach further enhances signal clarity and communication quality by leveraging orthogonal frequency division multiplexing(OFDM)technology.Simulation results show that the underwater acoustic channel with ARIS is superior to the traditional channel without ARIS in terms of bit error rate and anti-interference performance.This technology significantly enhances the reception quality of underwater communication signals,making it suitable for applications in marine monitoring,military communication,and other complex environments.
基金Project supported by the National Natural Science Foundation of China(No.61574045)
文摘A fourth-order Gm-C Chebyshev low-pass filter is presented as channel selection filter for reconfigurable multi-mode wireless receivers. Low-noise technologies are proposed in optimizing the noise characteristics of both the Gm cells and the filter topology. A frequency tuning strategy is used by tuning both the transconductance of the Gm cells and the capacitance of the capacitor banks. To achieve accurate cut-off frequencies, an on-chip calibration circuit is presented to compensate for the frequency inaccuracy introduced by process variation. The filter is fabricated in a 0.13 m CMOS process. It exhibits a wide programmable bandwidth from 322.5 k Hz to20 MHz. Measured results show that the filter has low input referred noise of 5.9 n V/（Hz）^（1/2） and high out-of-band IIP3 of 16.2 d Bm. It consumes 4.2 and 9.5 m W from a 1 V power supply at its lowest and highest cut-off frequencies respectively.
