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UltraJam:Ultrasonic adaptive jammer based on nonlinearity effect of microphone circuits

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高置信计算(英文) 2023年第3期3卷 30-39页

作者： Zhicheng Han Jun Ma Chao Xu Guoming Zhang School of Computer Qinghai Normal UniversityXining 810008China Department of Computer Science UC DavisDavis 95616USA School of Computer Science and Technology Shandong UniversityQingdao 266237China

The widely used devices(***,recorders)equipped with microphones have posed a severe threat to confidential *** this paper,we design an inaudible anti-eavesdropping method:UltraJam,to reduce the risk of unwanted and secret *** uses the ultrasonic signal to mask *** leveraging the nonlinear effect of microphone circuits,the adaptive ultrasonic signal can be recorded and demodulated into low-frequency which can effectively squash the *** on the characteristics of the attenuation coefficient and frequency response,we construct a number of jamming signals with different bandwidths and designed a wideband signal injection array,meanwhile adaptively adjust the power at each bandwidth signal to cover more frequency bands and increase usage *** verify the security of the microphone jamming system,we also utilize several audio recovery methods to recover the raw signal from jamming *** experimental results show that less than 1% of the words are recognized in the jamming recording,and even with the audio recovery method,99% of the words still cannot be recognized in the recovered jamming recording.

关键词： Noise jammer microphone Nonlinear effects Security

Modelling and Optimisation of a Spring-Supported Diaphragm Capacitive MEMS microphone

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Engineering（科研） 2010年第10期2卷 762-770页

作者： Norizan Mohamad Pio Iovenitti Thurai Vinay 不详

Audio applications such as mobile communication and hearing aid devices demand a small size but high performance, stable and low cost microphone to reproduce a high quality sound. Capacitive microphone can be designed to fulfill such requirements with some trade-offs between sensitivity, operating frequency range, and noise level mainly due to the effect of device structure dimensions and viscous damping. Smaller microphone size and air gap will gradually decrease its sensitivity and increase the viscous damping. The aim of this research was to develop a mathematical model of a spring-supported diaphragm capacitive MEMS microphone as well as an approach to optimize a microphone’s performance. Because of the complex shapes in this latest type of diaphragm design trend, analytical modelling has not been previously attempted. A novel diaphragm design is proposed that offers increased mechanical sensitivity of a capacitive microphone by reducing its diaphragm stiffness. A lumped element model of the spring-supported diaphragm microphone is developed to analyze the complex relations between the microphone performance factors and to find the optimum dimensions based on the design requirements. It is shown analytically that the spring dimensions of the spring-supported diaphragm do not have large effects on the microphone performance com pared to the diaphragm and backplate size, diaphragm thickness, and air-gap distance. A 1 mm2 spring-supported diaphragm microphone is designed using several optimized performance parameters to give a –3 dB operating bandwidth of 10.2 kHz, a sensitivity of 4.67 mV/Pa (–46.5 dB ref. 1 V/Pa at 1 kHz using a bias voltage of 3 V), a pull-in voltage of 13 V, and a thermal noise of –22 dBA SPL.

关键词： Capacitive microphone Spring-Supported Diaphragm microphone Modelling

Noise Source Identification Applied in Electric Power Industry Using microphone Arrays

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Engineering（科研） 2013年第1期5卷 152-156页

作者： Pengxiao Teng Rilin Chen Yichun Yang Key Laboratory of Noise and Vibration Research Chinese Academy of Sciences Beijing China

The noise source identification is an important issue in noise reduction and condition monitoring(CM) for machines in- site using microphone arrays. In this paper, we propose a new approach to optimize array configuration based on particles swarm optimization algorithm in order to improve noise source identification and condition monitoring performance. Two distinct optimized array configurations are designed under the certain conditions. Furthermore, an acoustic imaging equipment is developed to carry out experiments on transformer substation equipment and wind turbine generator, which demonstrate that the acoustic imaging system allows a high resolution in identifying main noise sources for noise reduction and abnormal noise sources for condition monitoring.

关键词： Noise Source Identification Condition Monitoring Noise Reduction microphone Array Particle Swarm Optimization

智能音响中MEMS microphone性能测试的实现过程

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科技创新与应用 2018年第14期8卷 61-62页

作者：周晨龙英华达(上海)科技有限公司上海201114

microphone作为人机交互的重要传感器广泛应用于智能手机,智能手环,平板电脑及智能音响等智能设备中,特别是MEMS(Micro-Electro Mechanical System微机电系统)microphone应用最为广泛。其优势在于体积小,受温度影响小,可使用SMT(Surface... 详细信息

microphone作为人机交互的重要传感器广泛应用于智能手机,智能手环,平板电脑及智能音响等智能设备中,特别是MEMS(Micro-Electro Mechanical System微机电系统)microphone应用最为广泛。其优势在于体积小,受温度影响小,可使用SMT(Surface Mount Technology表面贴装技术)制造,能够承受无铅制程所用的回流焊温度。如何检测MEMS microphone在经过高达260摄氏度的回流焊接及与机构件组装后的性能,成为电子制造生产过程中非常重要的一环。文章就智能音响中所用MEMS microphone在焊接及机构组装后,microphone性能的测试过程进行阐述研究。

关键词： MEMS microphone 智能音响测试过程

用传声器(microphone)预测蛛网膜下腔出血

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吉林大学学报(医学版) 1982年第4期 65-65页

作者：壮骥

本病为突然袭击性疾病,为壮年主要死因之一。对其病因的脑动脉瘤、动静脉畸形过去缺少简单的预测方法。直至出血后方以CT、脑血管造影而确诊。当然进行血管造影可以明确诊断,但对健康人无法进行此种并非完全无害的诊断方法。动脉瘤、动... 详细信息

本病为突然袭击性疾病,为壮年主要死因之一。对其病因的脑动脉瘤、动静脉畸形过去缺少简单的预测方法。直至出血后方以CT、脑血管造影而确诊。当然进行血管造影可以明确诊断,但对健康人无法进行此种并非完全无害的诊断方法。动脉瘤、动静脉畸形部位因血

关键词：传声器声级计 microphone 动静脉畸形

Experimental study on spectrum and multi-scale nature of wall pressure and velocity in turbulent boundary layer

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Chinese Physics B 2015年第6期24卷 385-394页

作者：郑小波姜楠 Department of Mechanics Tianjin University Tianjin Key Laboratory of Modern Engineering Mechanics The State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of Sciences

When using a miniature single sensor boundary layer probe, the time sequences of the stream-wise velocity in the turbulent boundary layer （TBL） are measured by using a hot wire anemometer. Beneath the fully developed TBL, the wall pressure fluctuations are attained by a microphone mechanism with high spatial resolution. Analysis on the statistic and spectrum properties of velocity and wall pressure reveals the relationship between the wall pressure fluctuation and the energy-containing structure in the buffer layer of the TBL. Wavelet transform shows the multi-scale natures of coherent structures contained in both signals of velocity and pressure. The most intermittent wall pressure scale is associated with the coherent structure in the buffer layer. Meanwhile the most energetic scale of velocity fluctuation at y＋ = 14 provides a specific frequency f9 ≈ 147 Hz for wall actuating control with Ret = 996.

关键词： multi-scale coherent structures hot wire anemometry microphone wavelet transform

About Multichannel Speech Signal Extraction and Separation Techniques

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Journal of Signal and Information Processing 2012年第2期3卷 238-247页

作者： Adel Hidri Souad Meddeb Hamid Amiri Signal Image and Technology of Information Laboratory National Engineering School of Tunis Tunis Tunisia

The extraction of a desired speech signal from a noisy environment has become a challenging issue. In the recent years, the scientific community has particularly focused on multichannel techniques which are dealt with in this review. In fact, this study tries to classify these multichannel techniques into three main ones: Beamforming, Independent Component Analysis (ICA) and Time Frequency (T-F) masking. This paper also highlights their advantages and drawbacks. However these previously mentioned techniques could not afford satisfactory results. This fact leads to the idea that a combination of those techniques, which is depicted along this study, may probably provide more efficient results. Indeed, giving the fact that those approaches are still be considered as being not totally efficient, has led us to review these mentioned above in the hope that further researches will provide this domain with suitable innovations.

关键词： Beamforming ICA T-F Masking BSS Multichannel Speech Separation microphone Array

Enhanced Frequency-Domain Frost Algorithm Using Conjugate Gradient Techniques for Speech Enhancement

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Journal of Electronic Science and Technology 2012年第2期10卷 158-162页

作者： Shengkui Zhao Douglas L. Jones Advanced Digital Sciences Center Singapore 138632 Singapore Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign Illinois USA

In this paper, the frequency-domain Frost algorithm is enhanced by using conjugate gradient techniques for speech enhancement. Unlike the non-adaptive approach of computing the optimum minimum variance distortionless response （MVDR） solution with the correlation matrix inversion, the Frost algorithm implementing the stochastic constrained least mean square （LMS） algorithm can adaptively converge to the MVDR solution in mean-square sense, but with a very slow convergence rate. In this paper, we propose a frequency-domain constrained conjugate gradient （FDCCG） algorithm to speed up the convergence. The devised FDCCG algorithm avoids the matrix inversion and exhibits fast convergence. The speech enhancement experiments for the target speech signal corrupted by two and five interfering speech signals are demonstrated by using a four-channel acoustic-vector-sensor （AVS） micro-phone array and show the superior performance.

关键词： Adaptive gence correlation speech arrays. signal processing conver- enhancement microphone

Estimation of Knock Wheel Noise of Rail Transport with an Acoustic Intensity Method

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Journal of Mechanics Engineering and Automation 2012年第8期2卷 465-469页

作者： Kolykhalin Vitaly St. Petersburg State University of Cinematography and Television St. Petersburg 191119 Russia

The application of railway wheel noise compensation method is considered. The effect can be obtained by shift a pair of usual parallel rail joints on a pair of offset rail joints, for example, the right rail joint is shifted concerning the left rail joint on the certain distance. The distance is depend on the speed of train and promotes the correlation interconnection between excited acoustical pulses. The intensity wheel knock spectrograms corresponding of different distance between rail joints registered by the microphone are estimated. The spectrograms considerably differed from each other in low frequency band are analyzed. The result of practical using the acoustic noise compensation method is proved.

关键词： Control noise acoustic railway microphone wheel knock.