Journal articles: 'Acoustic directivity acquisition system'

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Malarkodi, Amirthalingam, Peddinti SSR Sridhar, and Ganesan Latha. "Development of Automated Measurement Setup for Characterizing Underwater Acoustic Transducers." Marine Technology Society Journal 50, no. 6 (November 1, 2016): 69–75. http://dx.doi.org/10.4031/mtsj.50.6.9.

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AbstractAccurate determination of sensitivity and directivity is important for any underwater acoustic transducer. In this work, an automatic measuring platform was designed and implemented for characterizing underwater acoustic transducers. The overall hardware setup includes a PXI (PCI Extensions for Instrumentation)-based data acquisition system, computer-based controller module, motion controller module, and LabVIEW-based automatic calibration program. The system performs a sequence of operations automatically and achieves synchronous control of transmission and acquisition of real-time acoustic signals as well as processing, recording, and report generation. This measurement platform can be utilized for characterizing any type of acoustic transducer for its receiving sensitivity, transmitting response, and directivity measurement as per IEC60565 standard. The measurement results for RESON TC4034 and RESON TC 2080 transducers are presented and the results show that the system is able to carry out accurate calibration and characterization of any underwater acoustic transducer. Sources of uncertainty for calibration are also presented with the confidence level of approximately 95%.

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Wei, Zhou-Tuo, and Xiao-Ming Tang. "Numerical simulation of radiation, reflection, and reception of elastic waves from a borehole dipole source." GEOPHYSICS 77, no. 6 (November 1, 2012): D253—D261. http://dx.doi.org/10.1190/geo2012-0061.1.

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A recent advance in single-well reflection imaging is the use of a dipole acoustic system in a borehole to radiate and receive elastic waves to and from a remote geologic reflector in formation. This dipole-acoustic imaging technology is evaluated by numerically simulating the radiation and reflection of the wavefield generated by the borehole dipole source and analyzing the receiving sensitivity of the dipole system to the incoming reflected waves. The analyses show that a borehole dipole source can radiate a compressional wave (P-wave) and two types of shear waves (i.e., SV- and SH-waves) into the formation. The SH-wave has wide radiation coverage and the best receiving sensitivity, and is most suitable for dipole-shear imaging. In an acoustically slow formation, the dipole-generated P-wave has strong receiving sensitivity and can also be used for reflection imaging. An important feature of dipole imaging is its sensitivity to reflector azimuth, which results from the directivity of the dipole source. By using a 4C data acquisition method to record the dipole-generated reflected signal, the reflector azimuth can be determined. The numerical simulation and theoretical analysis results are in good agreement, providing a solid foundation for the dipole acoustic imaging technology.

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Zhong, Yu, and Yangting Liu. "Source-independent time-domain vector-acoustic full-waveform inversion." GEOPHYSICS 84, no. 4 (July 1, 2019): R489—R505. http://dx.doi.org/10.1190/geo2018-0304.1.

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Dual-sensor seismic acquisition systems that record the pressure and particle velocity allow the recording of the full-vector-acoustic (VA) wavefields. Most previous studies have focused on data-domain processing methods based on VA seismic data; whereas, few studies focused on using full-VA seismic data in full-waveform inversion (FWI). Conventional acoustic FWI only takes advantage of the pressure recordings to estimate the medium’s velocity model. Some artifact events will appear in the adjoint-state wavefields based on the conventional acoustic FWI method. These artifact events further reduce the accuracy of acoustic FWI. To simultaneously use pressure and vertical particle velocity recordings, we introduced a new time-domain VA FWI method. The VA FWI method can take advantage of directivity information contained in the VA seismic data. Thus, the adjoint-state wavefields based on VA FWI are more accurate than those from the conventional acoustic FWI method. In addition, we applied a convolution-based objective function to eliminate the effects of the source wavelet and implement a time-domain multiscale strategy in VA FWI. Synthetic examples are presented to demonstrate that VA FWI can improve the accuracy of acoustic FWI in the presence and absence of a free surface in the acoustic case. In addition, VA FWI does not significantly increase the computation and memory costs, but it has better convergence when compared with conventional acoustic FWI.

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Adachi, Ahoro, and Hiroyuki Hashiguchi. "Application of parametric speakers to radio acoustic sounding system." Atmospheric Measurement Techniques 12, no. 10 (October 28, 2019): 5699–715. http://dx.doi.org/10.5194/amt-12-5699-2019.

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Abstract. In this study, a wind profiler with a radio acoustic sounding system (RASS) and operational radiosonde measurements were used to investigate the technical practicability and reliability of using parametric speakers to measure the vertical profile of virtual temperature. Characteristics of parametric speakers include high directivity and very low side lobes, which are preferable for RASS, especially those operating in urban areas. The experiments were conducted on fine days with light winds to mitigate the effects of the horizontal and vertical components of wind on acoustic waves used for RASS. The results of this study indicated that, although parametric speaker RASS is susceptible to horizontal winds due to the narrower acoustic beam, bias and standard deviation of parametric speaker RASS versus radiosonde virtual temperature difference (0.1 ∘C, 0.4 ∘C) were close to those from acoustic speakers (0.0 ∘C, 0.4 ∘C). In addition, when compared with acoustic speaker RASS, the values for the parametric speaker RASS were even smaller (0.1 ∘C, 0.2 ∘C). Based on these results, it is concluded that the parametric speaker RASS has accuracy and precision comparable with acoustic speaker RASS despite its high directivity of sound.

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Cheng, Yue, Anbang Zhao, Juan Hui, Tiansi An, and Bin Zhou. "Parametric Underwater Transmission Based on Pattern Time Delay Shift Coding System." Mathematical Problems in Engineering 2018 (December 26, 2018): 1–7. http://dx.doi.org/10.1155/2018/8249245.

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The technique of pattern time delay shift coding (PDS) underwater acoustic (UWA) communication based on parametric array is presented in this paper, which is easy to be implemented and robust in the spatiotemporal variable ocean environment. The parametric array can generate low-frequency, broadband, and high-directivity beam with small-aperture. The high directivity reduces the impact of time variant characteristics of UWA channel especially multipath effects and improves the reuse rate of underwater acoustic channel at the same time. The wide bandwidth allows high rate communications. The sea trial results show that it can be employed to combat multipath propagation in shallow water and achieve very low bit error rate (BER). The theoretical research and sea trial verify the feasibility and effectiveness of the proposed UWA method.

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Vijay Yeole, Gaurav, and Sagar Ramchandra Shinde. "Acoustic Emission Signal Analysis using Data Acquisition System." International Journal of Engineering Trends and Technology 11, no. 8 (May 25, 2014): 384–87. http://dx.doi.org/10.14445/22315381/ijett-v11p275.

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Welch, John R. "System and method for calculating the directivity index of a passive acoustic array." Journal of the Acoustical Society of America 126, no. 2 (2009): 927. http://dx.doi.org/10.1121/1.3204321.

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You, Ting, Pei Jiang Li, Guan Jun Tong, and Jian Wei Shen. "Development of Acoustic Emission High-Speed Data Acquisition System." Advanced Materials Research 433-440 (January 2012): 5666–71. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.5666.

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Acoustic emission is generally high-frequency signal with the characteristics of broadband and burstiness, so it is very difficult to acquire acoustic emission signal in real time as well as rapidly, In this paper, an USB based acquisition system for acoustic emission signal is designed, which adopts CPLD as controller and uses two high-speed A/D converters to achieve synchronous acquisition of two-channel acoustic emission signals, The system first puts collected data into a FIFO and then transfers data to host through USB using CY7C68013, The sampling frequency of the system is up to 10MHz and the transmission rate of USB is 40M/S, Hard body impact test and lead-breaking test indicate that the system can achieve real-time acquisition of acoustic emission signal well,

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Qu, Ke, Binbin Zou, Jingjing Chen, Yingge Guo, and Runtian Wang. "Experimental Study of a Broadband Parametric Acoustic Array for Sub-Bottom Profiling in Shallow Water." Shock and Vibration 2018 (December 25, 2018): 1–8. http://dx.doi.org/10.1155/2018/3619257.

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Broadband parametric acoustic arrays appear to offer advantages for shallow water sub-bottom profiling. In this paper, the performance of a broadband parametric acoustic array system was experimentally evaluated. In tank experiments using the nonlinear parabolic wave (KZK) equation, the directivity, source level, parametric acoustic array length, and penetration depth were evaluated. Based on Berktay’s far-field solution, the system’s emission signal was designed. According to sea trials of the broadband parametric acoustic array system as designed, a clear sub-bottom profile was obtained. Moreover, buried pipelines in the seabed were effectively detected, verifying the system’s effectiveness.

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Wang, Tian, Meihui Gong, Xiaoyu Yu, Guangdong Lan, and Yunbo Shi. "Acoustic-pressure sensor array system for cardiac-sound acquisition." Biomedical Signal Processing and Control 69 (August 2021): 102836. http://dx.doi.org/10.1016/j.bspc.2021.102836.

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Jung, Donghwan, Jiyoung Song, Jeasoo Kim, and Jaehyuk Lee. "Comparative Experimental Investigation on Optimal Parametric Array Types." Sensors 21, no. 15 (July 27, 2021): 5085. http://dx.doi.org/10.3390/s21155085.

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As a sound transmitting device that relies on the nonlinearity of a medium, a parametric array (PA) can generate high-directivity low-frequency signals using a small aperture transducer and high-frequency signals. Despite their relatively low source level, the PA is frequently used to measure the acoustic properties of materials in low-frequency regions owing to their high directivity in confined acoustic water tanks. Therefore, methods for improving the source level of secondary signals are of interest. Currently, there are two driving methods for PA: the dual-frequency PA and the broadband PA with amplitude modulation. In this study, we share the results of an elaborate and comparative experimental investigation of these two driving methods. Comparisons are made and discussed in terms of the intensity of the generated secondary signal and its characteristics in the frequency domain. Based on these factors, we confirmed that the broadband PA was more suitable as the sound source of the low-frequency characteristic measurement system of acoustic materials.

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BESSET, SBASTIEN, M. N. ICHCHOU, and L. JÉZÉQUEL. "A COUPLED BEM AND ENERGY FLOW METHOD FOR MID-HIGH FREQUENCY INTERNAL ACOUSTIC." Journal of Computational Acoustics 18, no. 01 (March 2010): 69–85. http://dx.doi.org/10.1142/s0218396x10004073.

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This paper deals with the behavior of acoustic cavities in the mid-high frequency range. The method proposed here is based on an energy flow method named Simplified Energy Method (MES). MES method is quite efficient in the mid-high frequency range but the directivity of the boundary sources is not well estimated. We propose a hybrid method which couples MES and the Boundary Element Method (BEM). Thus, the BEM method is used to estimate the direct field, considering a "correct" directivity. As a complete calculation is not adapted to BEM in mid-high frequency range because of the calculation costs, we only apply BEM on the domains including boundary sources. Other parts of the system and the reverberated field are estimated by the mean of MES method. This hybrid method leads to a consistent prediction of injected power densities. Numerical comparisons prove the efficiency of the proposed reformulation.

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Zhao, Xinsa, Jianning Han, Peng Yang, and Rongrong Zhao. "Research on High-Efficiency Transmission Characteristics of Multi-Channel Breast Ultrasound Signals Based on Graphene Structure." Crystals 11, no. 5 (May 4, 2021): 507. http://dx.doi.org/10.3390/cryst11050507.

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In breast ultrasound CT imaging, the ultrasound signals received by high-density CMUT cylindrical array have problems of low transmission efficiency, susceptibility to interference from other signals, and an inability to achieve efficient acquisition. Therefore, to overcome these problems, based on acoustic metamaterials and graphene structure, an efficient transmission model of the multi-channel breast ultrasonic signals was designed, and a finite element simulation experiment was conducted. Research showed that the separation of ultrasonic signals could be achieved by the model designed in this article. The anti-interference ability in the ultrasonic signal acquisition process was effectively improved by the good multi-channel directional transmission and the sound wave local enhancement effect, which improved the sound wave transmission efficiency. In addition, the acoustic signals could be effectively transmitted from 80 kHz to 4000 kHz, realizing broadband transmission. Based on the flexibility of the design of the phononic crystal structure, phase adjustment could be achieved in a wide frequency range by changing the parameters of the primary cell structure. This enabled the CMUT cylindrical array to obtain better directivity characteristics, laying the foundation for high-quality breast ultrasound imaging.

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Feng, Ting, Jian De Wu, Xu Yi Yuan, Yu Gang Fan, and Xiao Dong Wang. "Design and Implementation of Valve Failure Signal Multi-Channel Acquisition System Based on Acoustic Emission and Pipeline." Advanced Materials Research 460 (February 2012): 281–85. http://dx.doi.org/10.4028/www.scientific.net/amr.460.281.

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Designed and implemented acoustic emission signal acquisition system core with microprocessor STM32F103RB. Acquisition system included high sensitivity acoustic emission sensors: PXR20; signal conditioning for acoustic emission, used high-speed ADC AD9225 for A/D conversion; used FIFO module for data buffer; used USB to serial port technology for data communications and transmissions. Central control unit design included gain control of amplifier circuit, clock control of external AD-chip and data cache chip, data acquisition port control, data output port control. Experimental results show that the system implements a multi-channel, parallel, high-precision acquisition and transmission for acoustic emission data.

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Zhang, Junmei, Yanyi Wang, Bowen Cheng, and Shuai Wang. "Design of Acoustic Emission Data Acquisition System of Wood Damage." International Journal of Control and Automation 8, no. 9 (September 30, 2015): 291–302. http://dx.doi.org/10.14257/ijca.2015.8.9.28.

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DINER, N., A. WEILL, J. Y. COAIL, and J. M. COUDEVILLE. "INES MOVIES : A NEW ACOUSTIC DATA ACQUISITION AND PROCESSING SYSTEM." Le Journal de Physique Colloques 51, no. C2 (February 1990): C2–939—C2–942. http://dx.doi.org/10.1051/jphyscol:19902219.

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Kuznetsov, V. N., A. V. Kulikov, A. V. Nosov, and T. G. Kharatishvili. "Multichannel system for the acquisition of high-frequency acoustic information." Soviet Journal of Physical Oceanography 1, no. 6 (November 1990): 479–81. http://dx.doi.org/10.1007/bf02197003.

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Brennan, T. J., N. S. Deno, and R. P. Gaumond. "Multichannel data acquisition system for recording the acoustic brainstem response." Electroencephalography and Clinical Neurophysiology 60, no. 2 (February 1985): 177–80. http://dx.doi.org/10.1016/0013-4694(85)90026-4.

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Liu, Yang, Yong Tie, Shun Na, and Dong Li. "Acoustic Signal Acquisition and Analysis System Based on Digital Signal Processor." Advanced Materials Research 518-523 (May 2012): 1436–41. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.1436.

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Leak detection and calibration of pipe internal roughness in a water distribution network are significant issue for environment pollution around the world. In recent years the problem of leak detection in pipelines, tanks, and process vessels has been the focus of many man-hours of effort. Acquisition the acoustic signal around the leakage to determine the location and size of leaks is emerging as an important tool. A double acoustic data acquisition and signal processing system based on the TI digital signal processor TMS320VC5410 and analog to digital converter TLC320AD50C is presented in this paper. The system design is introduced, with emphasis on the digital signal processor minimal system and TMS320VC5410 interface circuit which consists of two chips of A/D TLC320AD50C. The software development of the data acquisition and signal analysis is introduced. The system can be used in the application of real-time acoustic signal acquisition and leak location.

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Darras, Kevin, Bjørn Kolbrek, Andreas Knorr, Volker Meyer, and Mike Zippert. "Assembling cheap, high-performance microphones for recording terrestrial wildlife: the Sonitor system." F1000Research 7 (November 5, 2019): 1984. http://dx.doi.org/10.12688/f1000research.17511.2.

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Passive acoustic monitoring of wildlife requires sound recording systems. Several cheap, high-performance open-source solutions currently exist for recording soundscapes, but all of them are still reliant on commercial microphones. Commercial microphones are relatively expensive, specialized for particular taxa, and often have incomplete technical specifications. We designed Sonitor, an open-source microphone system to address all needs of ecologists that sample terrestrial wildlife acoustically. We evaluated the cost and durability of our system and measured trade-offs that are seldom acknowledged but which universally limit microphones' functions: weatherproofing versus sound attenuation, windproofing versus transmission loss after rain, signal loss in long cables, and analog sound amplification versus directivity with acoustic horns. We propose five microphone configurations suiting different budgets (from 8 to 33 EUR per unit), and fulfilling different sound quality and flexibility requirements. The Sonitor system consists of sturdy acoustic sensors that cover the entire sound frequency spectrum of sonant terrestrial wildlife at a fraction of the cost of commercial microphones.

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Darras, Kevin, Bjørn Kolbrek, Andreas Knorr, Volker Meyer, Mike Zippert, and Arne Wenzel. "Assembling cheap, high-performance microphones for recording terrestrial wildlife: the Sonitor system." F1000Research 7 (February 19, 2021): 1984. http://dx.doi.org/10.12688/f1000research.17511.3.

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Passive acoustic monitoring of wildlife requires sound recording systems. Several cheap, high-performance, or open-source solutions currently exist for recording soundscapes, but all rely on commercial microphones. Commercial microphones are relatively expensive, specialized for particular taxa, and often have incomplete technical specifications. We designed Sonitor, an open-source microphone system to address all needs of ecologists that sample terrestrial wildlife acoustically. We evaluated the cost and durability of our system and measured trade-offs that are seldom acknowledged but which universally limit microphones' functions: weatherproofing versus sound attenuation, windproofing versus transmission loss after rain, signal loss in long cables, and analog sound amplification versus directivity with acoustic horns. We propose five microphone configurations suiting different budgets (from 8 to 33 EUR per unit), and fulfilling different sound quality and flexibility requirements. The Sonitor system consists of sturdy acoustic sensors that cover the entire sound frequency spectrum of sonant terrestrial wildlife at a fraction of the cost of commercial microphones.

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Zhao, Guo Ku, Shu Shi Ning, Zhao Wei Cai, and Ze Qian Xu. "Design of the Underwater Acoustic Signal Acquisition System Based on the Pipelined Twin-AD." Advanced Materials Research 383-390 (November 2011): 497–502. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.497.

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In order to improve the accuracy of the underwater acoustic detection effectively, the digital signal acquisition circuxcA`\\it is a necessary deceive, which must have enough high data acquisition rate. Therefore the high frequency operating clock is employed in the traditional digital signal acquisition circuit. However, the high frequency operating clock will bring troubles to the design of hardware and software, and the power consumption and interference of the system are both increased. According to the principle of the pipelined system, the operation of AD deceive is divided into two process, including the conversion starting and data reading. The FPGA is employed to produce control signals which make twin-AD work in proper state. The design of the underwater acoustic signal acquisition system based on the pipelined twin-AD is presented here. On the base of the system design, simulation, implementation, the hardware experiments are completed. The results show: driven by the operating clock with same frequency, the underwater acoustic signal acquisition system based on the pipelined twin-AD can obtain the acquisition rate which is twice as the traditional data acquisition system.

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Sugar, Mitchell, and Paul Slaboch. "Directivity of sound propagation from an commercial supersonic engine inlet." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 2 (August 1, 2021): 4211–18. http://dx.doi.org/10.3397/in-2021-2633.

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The effects of mean flow variations on sound propagation from an axisymmetric commercial supersonic engine inlet were studied using numerical methods. A finite element model of the inlet was constructed in Ansys Fluent and used to solve for flow fields given by different initial conditions. Results from this model were fed into the aeroacoustic solver, Actran, and used to calculate far field radiated noise as well as the directivity of that noise. The acoustic source of this noise was a plane wave of a known strength placed at the fan face. In addition to assessing the effects of mean flow on the radiated noise transfer functions, the duct modes of the model were compared across different flow regimes. Relationships between mean flow parameters and the directivity of duct modes are developed. The results of this study will be used in further studies to gain a deeper understanding of how the underlying physics which govern the system create favorable or unfavorable directivity patterns.

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Darras, Kevin, Bjørn Kolbrek, Andreas Knorr, and Volker Meyer. "Assembling cheap, high-performance microphones for recording terrestrial wildlife: the Sonitor system." F1000Research 7 (December 28, 2018): 1984. http://dx.doi.org/10.12688/f1000research.17511.1.

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Passive acoustic monitoring of wildlife requires microphones. Several cheap, high-performance open-source solutions currently exist for recording sounds, but all of them are still reliant on commercial microphones. Commercial microphones are relatively expensive, specialized on particular taxa, and often have opaque technical specifications. We designed Sonitor, an open-source microphone system to address all needs of ecologists that sample terrestrial wildlife acoustically. We evaluated the cost of our system and measured trade-offs that are seldom acknowledged but which universally limit microphones' functions: weatherproofing versus sound attenuation, windproofing versus transmission loss after rain, signal loss in long cables, and analog sound amplification and directivity with acoustic horns. We propose three microphone configurations suiting different budgets, sound qualities, and flexibility requirements, which all cover the entire sound frequency spectrum of sonant terrestrial wildlife at a fraction of the cost of commercial microphones.

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Lin, Cong Ren, Sheng De Huang, and Fei Yuan. "Modified Short Baseline Acoustic Relative Localization System." Advanced Materials Research 655-657 (January 2013): 882–85. http://dx.doi.org/10.4028/www.scientific.net/amr.655-657.882.

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Underwater localization is a key element in most underwater communication applications. Since GPS signals highly attenuate in water, precise ranging based techniques for localization need to be developed. In this paper we describe a modified Short Baseline (SBL) acoustic localization system, in which a scheme of multi-channel data acquisition based on LabVIEW, the Generalized Cross Correlation (GCC) algorithm, and the hyperbolic positioning algorithm are used. Simulation results show that the modified SBL acoustic localization system that we proposed can adapt to the underwater harsh environment better, and also can reduce the position statistical error of underwater target significantly.

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Zhang, Rui, Wendong Zhang, Changde He, Jinlong Song, Linfeng Mu, Juan Cui, Yongmei Zhang, and Chenyang Xue. "Design of capacitive micromachined ultrasonic transducer (CMUT) linear array for underwater imaging." Sensor Review 36, no. 1 (January 18, 2016): 77–85. http://dx.doi.org/10.1108/sr-05-2015-0076.

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Purpose – The purpose of this paper was to develop a novel capacitive micromachined ultrasonic transducer (CMUT) reception and transmission linear array for underwater imaging at 400 kHz. Compared with traditional CMUTs, the developed transducer array offers higher electromechanical coupling coefficient and higher directivity performance. Design/methodology/approach – The configuration of the newly developed CMUT reception and transmission array was determined by the authors’ previous research into new element structures with patterned top electrodes and into directivity simulation analysis. Using the Si-Silicon on insulator (Si-SOI) bonding technique and the principle of acoustic impedance matching, the CMUT array was fabricated and packaged. In addition, underwater imaging system design and testing based on the packaged CMUT 1 × 16 array were completed. Findings – The simulation results showed that the optimized CMUT array configuration was selected. Furthermore, the designed configuration of the CMUT 1 × 16 linear array was good enough to guarantee high angular resolution. The underwater experiments were conducted to demonstrate that this CMUT array can be of great benefit in imaging applications. Practical implications – Based on our research, the CMUT linear array has good directivity and good impedance matching with water and can be used for obstacle avoidance, distance measurement and imaging underwater. Originality/value – This research provides a basis for CMUT directivity theory and array design. CMUT array presented in this paper has good directivity and has been applied in the underwater imaging, resulting in a huge market potential in underwater detection systems.

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Wright, Andrew B. "An inexpensive acoustic data acquisition system using a single-board microcomputer." Journal of the Acoustical Society of America 142, no. 4 (October 2017): 2729. http://dx.doi.org/10.1121/1.5014964.

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Kessissoglou, Nicole J., and Jie Pan. "Active Control of the Structural and Acoustic Responses of a Fluid-Loaded Plate; Part I: Analysis of the Physical System." Journal of Low Frequency Noise, Vibration and Active Control 17, no. 1 (March 1998): 11–25. http://dx.doi.org/10.1177/026309239801700102.

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The nature of the fluid–loading on a line–driven elastic plate significantly affects the structural and acoustic responses. As the fluid–loading increases, the fluid–structure interaction affects the wave propagation in the structure, as well as both the level and directivity of the sound radiation from the structure into the fluid field. The structural and acoustic responses of a line–force driven infinite plate under various fluid–loading conditions are considered. A detailed understanding of the fluid–structure interaction, including the effects of both heavy and light fluid–loading on the radiated sound pressure, sound power and structural response are clearly illustrated by numerical examples using the exact solution of the system equations. The results from this analysis of the physical system also provide useful information for the design of an active control system to effectively reduce the structural and acoustic responses of the fluid–loaded plate.

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Tan, Joe. "Wave-based control for nonreciprocal acoustics using a planar array of secondary sources." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 1 (August 1, 2021): 5446–56. http://dx.doi.org/10.3397/in-2021-3110.

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There has been significant interest in the design of nonreciprocal acoustic devices that allow acoustic waves to be perfectly transmitted in one direction, whilst the acoustic waves propagating in the opposite direction are blocked or reflected. Previously proposed nonreciprocal acoustic devices have broken the symmetry of transmission by introducing nonlinearities or resonant cavities. However, these nonreciprocal acoustic devices typically have limitations, such as signal distortions and the bandwidth over which nonreciprocal behaviour can be achieved is narrow. This paper will investigate how active control can be used to minimise the transmitted and reflected waves independently to achieve nonreciprocal sound transmission and absorption using a planar array of secondary sources in a two-dimensional environment. The advantage of the proposed active control system is that it is fully adaptable, which means that the directivity of nonreciprocal behaviour can also be reversed. The performance of the proposed wave-based active control system is investigated for a range of angles of incidence and its performance limitations are explored.

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Liu, Zhong Zhu, Chun Guang Xu, Xin Yu Zhao, and Xiang Hui Guo. "Development of a Practical Scanning Acoustic Microscopy." Advanced Materials Research 468-471 (February 2012): 1128–31. http://dx.doi.org/10.4028/www.scientific.net/amr.468-471.1128.

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Scanning acoustic microscopy (SAM) is a powerful non-destructive testing tool used in electronic, material and medical testing area. Commercial SAM products are generally too expensive to be extended to common users. Therefore, a practical SAM system had been developed using high-frequency ultrasonic focus transducers, a wide-band pulse transmitter/receiver, a high-speed data acquisition card, and a high-precision motion system. The SAM system's precision and function can meet the requirement of practical test adequately, and the cost is much lower compared to commercial products. Several kinds of imaging method were introduced, and the SAM system has the ability to accomplish full-wave data acquisition.

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Kusumah, Billi Rifa, Indra Jaya, Henry M. Manik, and Susilohadi. "ENGINEERING OF ACOUSTIC TECHNOLOGY FOR UNDERWATER POSITIONING OBJECT." Jurnal Ilmu dan Teknologi Kelautan Tropis 10, no. 3 (December 1, 2018): 629–37. http://dx.doi.org/10.29244/jitkt.v10i3.21456.

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Underwater Positioning System (UPS) is a system to track the existence of the position of an object by utilizing the arrival time of the signal measurement. On land, the system uses an electromagnetic signal called GPS. However, because it cannot penetrate water effectively, an acoustic signal is used as an alternative. The purpose of this research is to engineer the control system of data acquisition and underwater acoustic device to measure arrival time (TOA) and apply equation model for underwater sound source positioning system. the effective frequency resonance of the transducer and the hydrophone is at a frequency of 6 kHz. The acquisition control device is able to measure the TOA signal with an error on a digital channel smaller than an analog channel. The difference between the TOA values measured by oscilloscope and acquisition control system is caused by inaccuracy of threshold estimates at the receiver's peak detector circuit. The position of the sound source coordinates obtained from the equation model shows the highest difference in depth point (z) compared to points (x) and (y), caused by the equation model used is limited to four hydrophone units forming a horizontal baseline.

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Liu, Jing Jing, Lei Qin, Li Kun Wang, Chao Zhong, Bin Zhang, Chuan Xin Gu, and Dan Long. "A Flextensional Transducer Prototype with PVDF Piezoelectric Film." Applied Mechanics and Materials 670-671 (October 2014): 1153–58. http://dx.doi.org/10.4028/www.scientific.net/amm.670-671.1153.

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This paper presents a prototype of a new flextensional transducer with PVDF (Polyvinylidene Fluoride) piezoelectric film instead of metallic shell. Resonance frequency, bandwidth, transmitting voltage response, and horizontal directivity of the flextensional transducer with PVDF piezoelectric film were respectively measured by using laser-scanning vibrometer, and underwater acoustic measurement system. Experimental results showed that the new transducer features effectively conversion from longitudinal vibration of piezoelectric stack into radial vibration of PVDF piezoelectric film.

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Zhang, Wei Min, Shu Xuan Liu, Yong Qiu, and Cheng Feng Chen. "Study of the Metal Crack Propagation by Acoustic Emission Testing." Applied Mechanics and Materials 105-107 (September 2011): 2179–82. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.2179.

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Crack propagation is the main reason which leads to the invalidity of the metal components. A set of detecting equipment based on the acoustic emission method was designed, and it was mainly composed of acoustic emission sensor, signal operating circuits and signal acquisition system. Specimens of 16MnR material were manufactured and the static axial tension test of them was carried on. Acoustic emission signals from the specimen were detected by acoustic emission equipment by using piezoelectric ceramic sensor. Signal datum were acquired and operated by the acquisition system, as well as the acquisition program written for it. The final results has demonstrated that acoustic emission equipment designed for the test performed well in acquiring the signals induced by the metal crack propagation.

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Huang, Hui Yu, and Yang Hong. "Acoustic Emission Signal Acquisition and Analysis on Tool Wear." Key Engineering Materials 621 (August 2014): 171–78. http://dx.doi.org/10.4028/www.scientific.net/kem.621.171.

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In the field of machinery manufacture, broken state at the time of the cutting tool in cutting metal, recognition has always been a study is of great significance. Currently, for the state of tool wear and collapse edge damage identification method already has a mature experience. However the existing condition monitoring methods are often used in accuracy and convenience has limitations, this paper USES the acoustic emission technology, as a kind of integrated online test sys tem design lay the foundation. This paper aimed at the sensor in the wireless transmission module, the performance characteristics of tool condition monitoring system of the main structure was designed, and then by acoustic emission signal from the cutting tool in cutting process as the research object, studies the cutting tool characteristics of acoustic emission signal under different damage state, for the on-line monitoring system design and calibration to provide theoretical support.

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Shragge, Jeffrey, Jihyun Yang, Nader Issa, Michael Roelens, Michael Dentith, and Sascha Schediwy. "Low-frequency ambient distributed acoustic sensing (DAS): case study from Perth, Australia." Geophysical Journal International 226, no. 1 (March 26, 2021): 564–81. http://dx.doi.org/10.1093/gji/ggab111.

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SUMMARY Ambient wavefield data acquired on existing (so-called ‘dark fibre’) optical fibre networks using distributed acoustic sensing (DAS) interrogators allow users to conduct a wide range of subsurface imaging and inversion experiments. In particular, recorded low-frequency (<2 Hz) surface-wave information holds the promise of providing constraints on the shear-wave velocity (VS) to depths exceeding 0.5 km. However, surface-wave analysis can be made challenging by a number of acquisition factors that affect the amplitudes of measured DAS waveforms. To illustrate these sensitivity challenges, we present a low-frequency ambient wavefield investigation using a DAS data set acquired on a crooked-line optical fibre array deployed in suburban Perth, Western Australia. We record storm-induced microseism energy generated at the nearby Indian Ocean shelf break and/or coastline in a low-frequency band (0.04−1.80 Hz) and generate high-quality virtual shot gathers (VSGs) through cross-correlation and cross-coherence interferometric analyses. The resulting VSG volumes clearly exhibit surface wave energy, though with significant along-line amplitude variations that are due to the combined effects of ambient source directivity, crooked-line acquisition geometry and the applied gauge length, fibre coupling, among other factors. We transform the observed VSGs into dispersion images using two different methods: phase shift and high-resolution linear Radon transform. These dispersion images are then used to estimate 1-D near-surface VS models using multichannel analysis of surface waves (MASW), which involves picking and inverting the estimated Rayleigh-wave dispersion curves using the particle-swarm optimization global optimization algorithm. The MASW inversion results, combined with nearby deep borehole information and 2-D elastic finite-difference modeling, show that low-frequency ambient DAS data constrain the VS model, including a low-velocity channel, to at least 0.5 km depth. Thus, this case study illustrates the potential of using DAS technology as a tool for undertaking large-scale surface wave analysis in urban geophysical and geotechnical investigations to depths exceeding 0.5 km.

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TOKUOMI, Saeko, Kazuya MORI, and Yukimasa YANO. "1G2 Sound Acquisition System of Remote Impact Acoustic Testing for Concrete Structures." Proceedings of Conference of Kyushu Branch 2013 (2013): 199–200. http://dx.doi.org/10.1299/jsmekyushu.2013.199.

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Yang, Yang, Zhang Bingyang, Jiang Fuming, Hui Senxing, and Yin Qingrui. "Computer-controlled image acquisition and processed system for scanning electron -acoustic microscopy." Ferroelectrics 196, no. 1 (May 1997): 215–18. http://dx.doi.org/10.1080/00150199708224165.

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Xu, Zhen Ying, Jun Huang, Yang Yang Cai, and Shu Yuan Gao. "Design of Acoustic Emission Monitoring System for Defects of Hull Plate." Key Engineering Materials 568 (July 2013): 91–95. http://dx.doi.org/10.4028/www.scientific.net/kem.568.91.

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An acoustic emission (AE) monitoring system has been developed for micro cracks of hull plate, which has a human-machine interface (HMI) designed by Labview, with functions of signal acquisition, storage and replay, key parameters extraction. With the powerful signal processing capabilities of MATLAB, defects can be rapidly and accurately located.

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Wu, Hao, Zhi Qiang Fu, Wen Yue, and Cheng Biao Wang. "Study on Passive Acoustic Orienting System Based on Line Array of Microphone." Applied Mechanics and Materials 556-562 (May 2014): 4417–21. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.4417.

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The drawbacks of active object orienting system which is difficult to guarantee the concealment and security are obvious. Hence, the passive object orienting system becomes the research focus. Based on line array of microphone, the passive acoustic orienting system collects and records acoustic signals. The acoustic signals are processed by Conventional Beamforming (CBF) algorithm. The hardware of system is proved to be effective in the sound acquisition experiments. The results of acoustic orienting experiments are given, which shows that the error of acoustic orienting is less than 1%. The system which implements acoustic orienting and has a high accuracy is the base of the latter research in the laboratory.

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Huang, Ke, Zhi Kang Bu, Chi Zhang, and Heng Lian Xie. "The Design of Bearing Monitoring System Based on Acoustic Emission Signal." Applied Mechanics and Materials 716-717 (December 2014): 940–43. http://dx.doi.org/10.4028/www.scientific.net/amm.716-717.940.

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After experimental verification, in terms of low-speed bearing fault diagnosis, the acoustic emission method is superior to the traditional vibration method. In order to further the study of the correlation between AE signals and the bearing state, this article refers to the bearing condition monitoring system, and gives detailed parts models, the acoustic emission acquisition system, which provides help for further researches.

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Izquierdo Fuente, Alberto, Lara Del Val Puente, Juan J. Villacorta Calvo, and Mariano Raboso Mateos. "Optimization of a Biometric System Based on Acoustic Images." Scientific World Journal 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/780835.

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On the basis of an acoustic biometric system that captures 16 acoustic images of a person for 4 frequencies and 4 positions, a study was carried out to improve the performance of the system. On a first stage, an analysis to determine which images provide more information to the system was carried out showing that a set of 12 images allows the system to obtain results that are equivalent to using all of the 16 images. Finally, optimization techniques were used to obtain the set of weights associated with each acoustic image that maximizes the performance of the biometric system. These results improve significantly the performance of the preliminary system, while reducing the time of acquisition and computational burden, since the number of acoustic images was reduced.

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Lee, Jin-Hyuk. "Biomimetic idealization of a mechanically coupled acoustic sound sensing mechanism." SIMULATION 94, no. 2 (June 15, 2017): 131–43. http://dx.doi.org/10.1177/0037549717712038.

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This paper presents the idealization of a mechanically coupled acoustic sensor mechanism for directivity with the use of polysilicon, which has ideal mechanical and electrical material properties in terms of micro-fabrication. A mathematical model related to mechanical sensitivity is developed as a function of the material properties and geometry of the sensor, which evaluates the characteristics of a two-degree-of-freedom-based lumped parameter model. A challenge in such a study is that the model needs to be simple but sufficiently sophisticated to capture the characteristics of the sensor mechanism. Eigen modes and frequencies of the mechanically coupled acoustic sensor mechanism are determined by an energy method using mode functions applicable to the complete system that are from admissible the mode functions chosen for the component elements of the system. The synthesis is accomplished by using equations of constraint that follow conditions imposed by force equilibrium and deflection compatibility at the junctions. Finally, the results are compared with those obtained by a full-scale finite element model developed in a commercial software package. The predicted first and second natural frequencies differed by less than 10% and 3%, respectively, in all test cases.

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Li, Xin. "Design and implementation of an acoustic signal acquisition system based on Wi-Fi." Journal of the Acoustical Society of America 131, no. 4 (April 2012): 3483. http://dx.doi.org/10.1121/1.4709143.

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Moreno-Ramírez, Ciro, Carmen Iniesta, Alejandro González, and José Luis Olazagoitia. "Development and Characterization of a Low-Cost Sensors System for an Acoustic Test Bench." Sensors 20, no. 22 (November 20, 2020): 6663. http://dx.doi.org/10.3390/s20226663.

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Existing acoustic test benches are usually costly devices based on proprietary designs, sensors, and acquisition devices. In this paper, a low-cost test bench for acoustic purposes is introduced. The design of the test bench takes into account not only the low-cost mechanical design, but also uses low-cost sensors and control boards. This test bench has been designed for a range of signals compatible with those used by thermoacoustic engines, but it can be useful for applications with similar requirements. Taking advantage of an auxiliary pressure reference, low-cost unidirectional differential pressure sensors can be used to significantly increase the accuracy of the sampling system. The acoustic and mechanical design and development are presented along with the sampling system and the sensors arrangement implemented. Both the sensor and sampling system are evaluated by comparison with a high-fidelity sound acquisition system. An unexpected effect on the time error values distribution of the low-cost acquisition system is found and described. Finally, the errors introduced by the system and the sensors in terms of time and pressure sampling are characterized. As a result, the low-cost system’s accuracy has been satisfactory assessed and validated for the conditions expected in thermoacoustic experiments in terms of frequency and dynamic pressure.

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Urn, Tze W., and John R. Potter. "Pop-up Ambient Noise Data Acquisition (PANDA) System." Marine Technology Society Journal 33, no. 1 (January 1, 1999): 45–54. http://dx.doi.org/10.4031/mtsj.33.1.6.

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The Pop-up Ambient Noise Data Acquisition (PANDA) system described in this paper is a compact, cost-effective and self-contained submerged data acquisition system for collecting acoustic data. PANDA can be bottom-mounted, collecting data without surface eocpression, making it ideal for collecting data in high shipping and/or fishing activity locations. Assembled largely from “commercial off-the-shelf (COTS) components, the design time and unit cost have been minimised without compromising reliability. The electronic design is based on a PC motherboard computer system. The system as currently configured has a maximum sampling rate of 330 kHz and a maximum storage capacity of 1.2 GB. These values can be changed simply by exchanging COTS plug-in components. This flexibility of design, permitting the configuration to be changed quickly and cheaply to suit different deployment requirements, is an important feature of the system. The system can also be configured to record from multiple transducers of all types. PANDA was designed and built in 7 months, and is currently being used to collect long-term samples of ambient noise for ship noise analysis. Some example data are presented to illustrate the system’s capability.

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Yang, Shi Feng, Long Xue, and Ji Min Zhao. "Detecting System of Crop Disease Stress Based on Acoustic Emission and Virtual Technology." Applied Mechanics and Materials 556-562 (May 2014): 3331–34. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.3331.

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A system for detecting the conditions of crop disease stress by acoustic emission technology was studied and developed .The PCI-2 acoustic emission board and R15 acoustic emission sensor probes were chosen to construct the hardware detecting system, and the AEWIN software and virtual instrument technology were utilized to construct the software system, a real-time acquisition and detecting system for the information between acoustic emission and disease stress of crop was established. The results show that there are a certain physiological cycle laws in the acoustic emission of healthy crop, generally the “double peak area” can appear; but distortion can occur in the acoustic emission of disease stressed crop, a sharp increase of the acoustic emission frequency can suddenly take place at some time, immediately the crop begins to show disease symptoms, and acoustic emission signals lose the regularity.

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Li, Pei Jiang, and Ting You. "A Study on Monitoring System for Grinding Wheel Status Based on Acoustic Emission Technology." Applied Mechanics and Materials 52-54 (March 2011): 2051–55. http://dx.doi.org/10.4028/www.scientific.net/amm.52-54.2051.

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The grinding wheel wear status is an important guarantee for the processing efficiency and processing quality of precision and super precision grinding. In this paper, a USB acoustic emission signal acquisition system is designed for online monitoring of grinding wheel status. In the system, CPLD is used as the controller, and a high-speed A/D converter is used to implement the synchronous acquisition of acoustic emission array signals. The collected data are sent into FIFO, and CY7C68013A is used for USB data transmission with upper computer. The sampling frequency of the system can be 10 MHz, and USB transmission speed can reach 40M/S. It is proved that it can meet the monitoring requirements of grinding wheel wear status well by the grinding processing.

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Vasconcelos, Ivan. "Source-receiver, reverse-time imaging of dual-source, vector-acoustic seismic data." GEOPHYSICS 78, no. 2 (March 1, 2013): WA123—WA145. http://dx.doi.org/10.1190/geo2012-0300.1.

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Novel technologies in seismic data acquisition allow for recording full vector-acoustic (VA) data: pointwise recordings of pressure and its multicomponent gradient, excited by pressure only as well as dipole/gradient sources. Building on recent connections between imaging and seismic interferometry, we present a wave-equation-based, nonlinear, reverse-time imaging approach that takes full advantage of dual-source multicomponent data. The method’s formulation relies on source-receiver scattering reciprocity, thus making proper use of VA fields in the wavefield extrapolation and imaging condition steps in a self-consistent manner. The VA imaging method is capable of simultaneously focusing energy from all in- and outgoing waves: The receiver-side up- and downgoing (receiver ghosts) fields are handled by the VA receiver extrapolation, whereas source-side in- and outgoing (source ghosts) arrivals are accounted for when combining dual-source data at the imaging condition. Additionally, VA imaging handles image amplitudes better than conventional reverse-time migration because it properly handles finite-aperture directivity directly from dual-source, 4C data. For nonlinear imaging, we provide a complete source-receiver framework that relies only on surface integrals, thus being computationally applicable to practical problems. The nonlinear image can be implicitly interpreted as a superposition of several nonlinear interactions between scattering components of data with those corresponding to the extrapolators (i.e., to the model). We demonstrate various features of the method using synthetic examples with complex subsurface features. The numerical results show, e.g., that the dual-source, VA image retrieves subsurface features with “super-resolution”, i.e., with resolution higher than the limits of Born imaging, but at the cost of introducing image artifacts not present in the linear image. Although the method does not require any deghosting as a preprocessing step, it can use separated up- and downgoing fields to generate independent subsurface images.

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Shi, De Quan, and Gui Li Gao. "System for Detecting the Defects of Steel Tubes Based on Electromagnetic Acoustic Technology." Advanced Materials Research 383-390 (November 2011): 5339–43. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.5339.

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According to the electromagnetic acoustic technology, an automatic system was constructed to detect the defects of steel tubes. On the basis of analyzing the principle of detecting the defects of steel tubes by the electromagnetic acoustic technology, an electromagnetic acoustic transducer was designed to transmit and receive the electromagnetic acoustic signals. The data were acquired by the high-speed data acquisition card and transferred to computer by PCI bus, and then analyzed and processed by computer. In addition, the selective frequency and amplification technology was used to process the weak received signal, which improved the anti-jamming ability of the system. Experiments on steel tubes with different diameter through-hole were performed, and the res

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Wu, Fei, Xi Wang, Wei Wu Zhong, Hui Yu, Li Bing Liu, and Dong Ting Liao. "Based on Multi-Sensor Tool Steel Hard Turning Process Monitoring and Controlling." Advanced Materials Research 108-111 (May 2010): 549–55. http://dx.doi.org/10.4028/www.scientific.net/amr.108-111.549.

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Through a set of electro-hydraulic digital valve as the core of the fuzzy control system to provide an appropriate amount of cooling fluid, the hard turning process temperature can be controlled at any set temperature. The use of the signal acquisition system based on virtual instrument, acquisition acoustic emission signals, vibration signals and temperature signals during the hard turning process. The temperature signal is processed by wavelet transform ,after vibration and acoustic emission signals be processed by wavelet packet decomposition and energy method, it is found that through providing appropriate cooling fluid can control temperatures in the processing and decrease the amplitude of vibration and acoustic emission signal, it also means that we can improve the quality of processing, and prolong the life of tool.

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Journal articles on the topic 'Acoustic directivity acquisition system'

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