A low power 433 MHz CMOS （complementary metal- oxide-semiconductor transistor） low noise amplifier（LNA）, used for an ISM （ industrial-scientific-medical ） receiver, is implemented in a 0. 18 μm SMIC mixed-signa...A low power 433 MHz CMOS （complementary metal- oxide-semiconductor transistor） low noise amplifier（LNA）, used for an ISM （ industrial-scientific-medical ） receiver, is implemented in a 0. 18 μm SMIC mixed-signal and RF （ radio frequency） CMOS process. The optimal noise performance of the CMOS LNA is achieved by adjusting the source degeneration inductance and by inserting an appropriate capacitance in parallel with the input transistor of the LNA. The measured results show that at 431 MHz the LNA has a noise figure of 2.4 dB. The S21 is equal to 16 dB, S11 = -11 dB, S22 = -9 dB, and the inverse isolation is 35 dB. The measured input 1-dB compression point （PtdB） and input third-order intermodulation product （IIP3）are - 13 dBm and -3 dBm, respectively. The chip area is 0. 55 mm × 1.2 mm and the DC power consumption is only 4 mW under a 1.8 V voltage supply.展开更多
The noise generated by high-speed hair dryers significantly affects user experience,with aerodynamic design playing a crucial role in controlling sound emissions.This study investigates the aerodynamic noise character...The noise generated by high-speed hair dryers significantly affects user experience,with aerodynamic design playing a crucial role in controlling sound emissions.This study investigates the aerodynamic noise characteristics of a commercial high-speed hair dryer through Computational Fluid Dynamics(CFD)analysis.The velocity field,streamline patterns,and vector distribution within the primary flow path and internal cavity were systematically examined.Results indicate that strong interactions between the wake flow generated by the guide vanes and the straight baffle in the rear flow path induce vortex structures near the outlet,which are primarily responsible for highfrequency noise.To address this,the guide vanes and rear flow path geometry were redesigned and optimized for improved acoustic and aerodynamic performance.Underrated operating conditions(28 V,20,000 rpm),the optimized configuration achieves a noise reduction of more than 2.2 dB while increasing outlet wind speed by over 9%.Moreover,the noise suppression effect becomes more pronounced at lower rotational speeds.展开更多
In the design of the motor used for electric vehicles(EVS),vibration and noise problems are often ignored,which reduce the reliability and service life of the motor.In this paper,an interior permanent magnet synchrono...In the design of the motor used for electric vehicles(EVS),vibration and noise problems are often ignored,which reduce the reliability and service life of the motor.In this paper,an interior permanent magnet synchronous motor(IPMSM)with high power density is taken as an example,and its electromagnetic vibration and noise problem is investigated and optimized.Firstly,the factors that generate the electromagnetic force harmonic of IPMSM are analyzed by theoretical derivation.Furthermore,the mode and electromagnetic harmonic distribution of the motor are calculated and analyzed by establishing the electromagnetic-structure-sound coupling simulation model.Then,by combining finite element method(FEM)with modern optimization algorithm,an electromagnetic vibration and noise performance optimization method is proposed in the electromagnetic design stage of the motor.Finally,an IPMSM is optimized by this method for electromagnetic vibration and noise performance.The results of comparison between before and after optimization prove the feasibility of the method.展开更多
With the emergence of new attack techniques,traffic classifiers usually fail to maintain the expected performance in real-world network environments.In order to have sufficient generalizability to deal with unknown ma...With the emergence of new attack techniques,traffic classifiers usually fail to maintain the expected performance in real-world network environments.In order to have sufficient generalizability to deal with unknown malicious samples,they require a large number of new samples for retraining.Considering the cost of data collection and labeling,data augmentation is an ideal solution.We propose an optimized noise-based traffic data augmentation system,ONTDAS.The system uses a gradient-based searching algorithm and an improved Bayesian optimizer to obtain optimized noise.The noise is injected into the original samples for data augmentation.Then,an improved bagging algorithm is used to integrate all the base traffic classifiers trained on noised datasets.The experiments verify ONTDAS on 6 types of base classifiers and 4 publicly available datasets respectively.The results show that ONTDAS can effectively enhance the traffic classifiers’performance and significantly improve their generalizability on unknown malicious samples.The system can also alleviate dataset imbalance.Moreover,the performance of ONTDAS is significantly superior to the existing data augmentation methods mentioned.展开更多
A systematic approach is used to analyze the noise in CMOS low noise amplifier(LNA),including channel noise and induced gate noise in MOS devices.A new analytical formula for noise figure is proposed.Based on this for...A systematic approach is used to analyze the noise in CMOS low noise amplifier(LNA),including channel noise and induced gate noise in MOS devices.A new analytical formula for noise figure is proposed.Based on this formula,the impacts of distributed gate resistance and intrinsic channel resistance on noise performance are discussed.Two kinds of noise optimization approaches are performed and applied to the design of a 5 2GHz CMOS LNA.展开更多
In order to suppress the noise of gyroscopes,the method based on lock-in amplifier and capacitor matching of the low-noise readout circuit is proposed. Firstly,the principle to suppress the noise by lock-in amplifier ...In order to suppress the noise of gyroscopes,the method based on lock-in amplifier and capacitor matching of the low-noise readout circuit is proposed. Firstly,the principle to suppress the noise by lock-in amplifier is analyzed,and the noise model of front end is proposed. Secondly,the noise optimization for the charge amplifier is presented according to the noise model of front end. Finally,a readout circuit is constructed by this approach. The measurement results show that the parasitic capacitance of front end is 18 p F,and the noise at resonant frequency( 4 k Hz) is 133 n V / Hz1 / 2,and the overall bias stability is 30° /h,and the noise level is 0. 003° /( s·Hz1 / 2). The noise of the gyroscope with the low-noise readout by this method is suppressed effectively.展开更多
A minimal cellular automaton model is introduced to describe the collective motion of self-propelled particles on two-dimensional square lattice. The model features discretization of directional and positional spaces ...A minimal cellular automaton model is introduced to describe the collective motion of self-propelled particles on two-dimensional square lattice. The model features discretization of directional and positional spaces and single-particle occupation on one lattice site. Contrary to the Vicsek model and its variants, our model exhibits the nonvanishing optimal noise. When the particle density increases, the collective motion is promoted with optimal noise strength and reduced with noise strength out of optimal region. In addition, when the square lattice undergoes edge percolation process, no abrupt change of alignment behaviors is observed at the critical point of percolation.展开更多
Novel schemes for a charge sensitive amplifier （CSA） and a CR-（RC）, semi-Gaussian shaper in a fully integrated CMOS readout circuit for particle detectors are presented. The CSA is designed with poly-resistors as ...Novel schemes for a charge sensitive amplifier （CSA） and a CR-（RC）, semi-Gaussian shaper in a fully integrated CMOS readout circuit for particle detectors are presented. The CSA is designed with poly-resistors as feedback components to reduce noise. Compared with conventional CSA, the input referred equivalent noise charge（ENC） is simulated to be reduced from 5036e to 2381e with a large detector capacitance of 150pF at the cost of 0.5V output swing loss. The CR-（RC）,semi-Gaussian shaper uses MOS transistors in the triode region in series with poly-resistors to compensate process variation without much linearity reduction.展开更多
The transition to turbulence in flows where the laminar profile is linearly stable requires perturbations of finite amplitude. ＂Optimal＂ perturbations are distinguished as extrema of certain functionals, and differe...The transition to turbulence in flows where the laminar profile is linearly stable requires perturbations of finite amplitude. ＂Optimal＂ perturbations are distinguished as extrema of certain functionals, and different functionals give different optima. We here discuss the phase space structure of a 2D simplified model of the transition to turbulence and discuss optimal perturbations with respect to three criteria： energy of the initial condition, energy dissipation of the initial condition, and amplitude of noise in a stochastic transition. We find that the states triggering the transition are different in the three cases, but show the same scaling with Reynolds number.展开更多
Preamplifier circuit noise is of great importance in quartz enhanced photoacoustic spectroscopy （QEPAS） system. In this paper, several noise sources are evaluated and discussed in detail. Based on the noise characte...Preamplifier circuit noise is of great importance in quartz enhanced photoacoustic spectroscopy （QEPAS） system. In this paper, several noise sources are evaluated and discussed in detail. Based on the noise characteristics, the corresponding noise reduction method is proposed. In addition, a frequency locked technique is introduced to further optimize the QEPAS system noise and improve signal, which achieves a better performance than the conventional frequency scan method. As a result, the signal-to-noise ratio （SNR） could be increased 14 times by utilizing frequency locked technique and numerical averaging technique in the QEPAS system for water vapor detection.展开更多
Two different LNA design techniques,namely the classical two-port technique and the Shaeffer technique, have been introduced,compared and implemented for practical design.Their merits and drawbacks are also discussed....Two different LNA design techniques,namely the classical two-port technique and the Shaeffer technique, have been introduced,compared and implemented for practical design.Their merits and drawbacks are also discussed.This paper mainly focuses on the former technique,which is seldom introduced in traditional papers. Since a parasitic capacitor of the transistor is included in the computation of the former technique,the errors caused by the ignorance of the capacitor have been minimized,which is superior to traditional techniques.Using the former technique,a fully integrated LNA is realized with only 1.4 dB while drawing 1.3 mA DC at 2.4 GHz for simulation results.Another version of the LNA is designed using the latter technique,which has been fabricated.展开更多
基金The National Natural Science Foundation of China (No.60772008)the Key Science and Technology Program of Zhejiang Province(No.G2006C13024)
文摘A low power 433 MHz CMOS （complementary metal- oxide-semiconductor transistor） low noise amplifier（LNA）, used for an ISM （ industrial-scientific-medical ） receiver, is implemented in a 0. 18 μm SMIC mixed-signal and RF （ radio frequency） CMOS process. The optimal noise performance of the CMOS LNA is achieved by adjusting the source degeneration inductance and by inserting an appropriate capacitance in parallel with the input transistor of the LNA. The measured results show that at 431 MHz the LNA has a noise figure of 2.4 dB. The S21 is equal to 16 dB, S11 = -11 dB, S22 = -9 dB, and the inverse isolation is 35 dB. The measured input 1-dB compression point （PtdB） and input third-order intermodulation product （IIP3）are - 13 dBm and -3 dBm, respectively. The chip area is 0. 55 mm × 1.2 mm and the DC power consumption is only 4 mW under a 1.8 V voltage supply.
基金supported by Research Project of Zhuhai City Polytechnic(Grant No.2024KYBS06)Education Research Project of Zhuhai City Polytechnic(Grant No.JY20250404).
文摘The noise generated by high-speed hair dryers significantly affects user experience,with aerodynamic design playing a crucial role in controlling sound emissions.This study investigates the aerodynamic noise characteristics of a commercial high-speed hair dryer through Computational Fluid Dynamics(CFD)analysis.The velocity field,streamline patterns,and vector distribution within the primary flow path and internal cavity were systematically examined.Results indicate that strong interactions between the wake flow generated by the guide vanes and the straight baffle in the rear flow path induce vortex structures near the outlet,which are primarily responsible for highfrequency noise.To address this,the guide vanes and rear flow path geometry were redesigned and optimized for improved acoustic and aerodynamic performance.Underrated operating conditions(28 V,20,000 rpm),the optimized configuration achieves a noise reduction of more than 2.2 dB while increasing outlet wind speed by over 9%.Moreover,the noise suppression effect becomes more pronounced at lower rotational speeds.
基金This work was supported by the Fundamental Research Funds for the Central Universities(No.2019YJS181).
文摘In the design of the motor used for electric vehicles(EVS),vibration and noise problems are often ignored,which reduce the reliability and service life of the motor.In this paper,an interior permanent magnet synchronous motor(IPMSM)with high power density is taken as an example,and its electromagnetic vibration and noise problem is investigated and optimized.Firstly,the factors that generate the electromagnetic force harmonic of IPMSM are analyzed by theoretical derivation.Furthermore,the mode and electromagnetic harmonic distribution of the motor are calculated and analyzed by establishing the electromagnetic-structure-sound coupling simulation model.Then,by combining finite element method(FEM)with modern optimization algorithm,an electromagnetic vibration and noise performance optimization method is proposed in the electromagnetic design stage of the motor.Finally,an IPMSM is optimized by this method for electromagnetic vibration and noise performance.The results of comparison between before and after optimization prove the feasibility of the method.
基金supported in part by the National Key Research and Development Program of China(No.2022YFB4500800)the National Science Foundation of China(No.42071431).
文摘With the emergence of new attack techniques,traffic classifiers usually fail to maintain the expected performance in real-world network environments.In order to have sufficient generalizability to deal with unknown malicious samples,they require a large number of new samples for retraining.Considering the cost of data collection and labeling,data augmentation is an ideal solution.We propose an optimized noise-based traffic data augmentation system,ONTDAS.The system uses a gradient-based searching algorithm and an improved Bayesian optimizer to obtain optimized noise.The noise is injected into the original samples for data augmentation.Then,an improved bagging algorithm is used to integrate all the base traffic classifiers trained on noised datasets.The experiments verify ONTDAS on 6 types of base classifiers and 4 publicly available datasets respectively.The results show that ONTDAS can effectively enhance the traffic classifiers’performance and significantly improve their generalizability on unknown malicious samples.The system can also alleviate dataset imbalance.Moreover,the performance of ONTDAS is significantly superior to the existing data augmentation methods mentioned.
文摘A systematic approach is used to analyze the noise in CMOS low noise amplifier(LNA),including channel noise and induced gate noise in MOS devices.A new analytical formula for noise figure is proposed.Based on this formula,the impacts of distributed gate resistance and intrinsic channel resistance on noise performance are discussed.Two kinds of noise optimization approaches are performed and applied to the design of a 5 2GHz CMOS LNA.
文摘In order to suppress the noise of gyroscopes,the method based on lock-in amplifier and capacitor matching of the low-noise readout circuit is proposed. Firstly,the principle to suppress the noise by lock-in amplifier is analyzed,and the noise model of front end is proposed. Secondly,the noise optimization for the charge amplifier is presented according to the noise model of front end. Finally,a readout circuit is constructed by this approach. The measurement results show that the parasitic capacitance of front end is 18 p F,and the noise at resonant frequency( 4 k Hz) is 133 n V / Hz1 / 2,and the overall bias stability is 30° /h,and the noise level is 0. 003° /( s·Hz1 / 2). The noise of the gyroscope with the low-noise readout by this method is suppressed effectively.
基金Project supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB33000000)the National Natural Science Foundation of China(Grant No.12090054)。
文摘A minimal cellular automaton model is introduced to describe the collective motion of self-propelled particles on two-dimensional square lattice. The model features discretization of directional and positional spaces and single-particle occupation on one lattice site. Contrary to the Vicsek model and its variants, our model exhibits the nonvanishing optimal noise. When the particle density increases, the collective motion is promoted with optimal noise strength and reduced with noise strength out of optimal region. In addition, when the square lattice undergoes edge percolation process, no abrupt change of alignment behaviors is observed at the critical point of percolation.
文摘Novel schemes for a charge sensitive amplifier （CSA） and a CR-（RC）, semi-Gaussian shaper in a fully integrated CMOS readout circuit for particle detectors are presented. The CSA is designed with poly-resistors as feedback components to reduce noise. Compared with conventional CSA, the input referred equivalent noise charge（ENC） is simulated to be reduced from 5036e to 2381e with a large detector capacitance of 150pF at the cost of 0.5V output swing loss. The CR-（RC）,semi-Gaussian shaper uses MOS transistors in the triode region in series with poly-resistors to compensate process variation without much linearity reduction.
基金supported in part by the German Research Foundation within FOR 1182
文摘The transition to turbulence in flows where the laminar profile is linearly stable requires perturbations of finite amplitude. ＂Optimal＂ perturbations are distinguished as extrema of certain functionals, and different functionals give different optima. We here discuss the phase space structure of a 2D simplified model of the transition to turbulence and discuss optimal perturbations with respect to three criteria： energy of the initial condition, energy dissipation of the initial condition, and amplitude of noise in a stochastic transition. We find that the states triggering the transition are different in the three cases, but show the same scaling with Reynolds number.
基金This work was supported by the National Natural Science Foundation of China （Grant Nos. 61405105 ＆ 61475085）, the Shandong Provincial Natural Science Foundation, China （Grant No. ZR2014FQ015）, Science and Technology Development Project of Shandong Province （Grant No. 2014GGX101007）, and the Fundamental Research Funds of Shandong University （Grant Nos. 2014HW016 ＆ 2014YQ011）.
文摘Preamplifier circuit noise is of great importance in quartz enhanced photoacoustic spectroscopy （QEPAS） system. In this paper, several noise sources are evaluated and discussed in detail. Based on the noise characteristics, the corresponding noise reduction method is proposed. In addition, a frequency locked technique is introduced to further optimize the QEPAS system noise and improve signal, which achieves a better performance than the conventional frequency scan method. As a result, the signal-to-noise ratio （SNR） could be increased 14 times by utilizing frequency locked technique and numerical averaging technique in the QEPAS system for water vapor detection.
文摘Two different LNA design techniques,namely the classical two-port technique and the Shaeffer technique, have been introduced,compared and implemented for practical design.Their merits and drawbacks are also discussed.This paper mainly focuses on the former technique,which is seldom introduced in traditional papers. Since a parasitic capacitor of the transistor is included in the computation of the former technique,the errors caused by the ignorance of the capacitor have been minimized,which is superior to traditional techniques.Using the former technique,a fully integrated LNA is realized with only 1.4 dB while drawing 1.3 mA DC at 2.4 GHz for simulation results.Another version of the LNA is designed using the latter technique,which has been fabricated.
