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Modified ultrasonic time-of-flight diffraction testing with barker code excitation for sizing inclined crack

APPLIED ACOUSTICS 2018年 140卷 153-159页

作者： Han, Qingbang Wang, Peng Zheng, Hao Ho Hai Univ Coll IOT Engn Changzhou Peoples R China

Effectively sizing inclined cracks inside material is a difficult issue in ultrasonic non-destructive testing. To size the length, depth and orientation of inclined crack, a modified ultrasonic time-of-flight diffraction testing with double receivers (DR-TOFD) using barker code excitation is proposed. The DR-TOFD technique is excited by barker code, which has accurate time precision, and the diffraction wave of the crack tips is received by two receivers. The diffraction signals are compressed by matched filter to obtain desired detecting signals, which are used to estimate the length, depth and orientation of crack. Finite element method, which simulates wave propagation in specimen with a 6 mm crack with different inclination angles, is used to evaluate the detecting ability of the DR-TOFD with barker code excitation. The simulation results show that the time precision of the proposed technique is up to 0.01 mu s. Experiment is also performed to verify the detecting ability of DR-TOFD. The experiment results show that the proposed technique is able to expediently and accurately size inclined crack.

关键词： NDT TOFD Inclined crack barker code

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A novel carrier frequency offset algorithm based on a double barker code in VDE-TER

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PHYSICAL COMMUNICATION 2020年 40卷 101059-101059页

作者： Hu, Qing Jing, Xiaoyue Lu, Pengfei Sun, Qian Huang, Jianlin Dalian Maritime Univ Dalian Peoples R China China Waterborne Transport Res Inst Beijing Peoples R China

The Maritime Very High Frequency (VHF) Data Exchange System (VDES) is a basic method of data exchange in the e-Navigation strategy proposed by the International Maritime Organization (IMO). Regarding the synchronization of the VDE-terrestrial (VDE-TER) communication carrier frequency, using the special structure of the training sequence in a VDE message frame, we propose a novel carrier frequency offset (CFO) estimation algorithm based on the phase difference between the barker code and its inverse code. We derive the principle model for the barker code and anti-barker code algorithm and analyze the frequency offset estimation performance of the proposed algorithm with those of the Fitz, L&R and M&M algorithms. We also present a real-world experiment conducted using a software-defined radio (SDR) platform. The results show that in the VDE-TER channel, the double barker code (DBC) carrier frequency offset estimation algorithm has good estimation performance and estimations range within the visible range. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Very High Frequency Data Exchange System (VDES) VDE-terrestrial (VDE-TER) Carrier frequency offset (CFO) barker code Software-defined radio (SDR)

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ULTRASONIC NON-DESTRUCTIVE TESTING USING barker code PULSE-COMPRESSION TECHNIQUES

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ULTRASONICS 1988年第1期26卷 23-26页

作者： CHEN, WH DENG, JL Department of Applied Physics Chung Cheng Institute of Technology Tahsi Taoyuan Taiwan Republic of China

A phase-coded pulse compression system, which consists of a barker code generator and a matched filter, has been implemented and applied to the ultrasonic non-destructive testing of materials. The 13-bit barker code with a bit interval of 200 ns is achieved and the matched filter is constructed using a charge coupled device (CCD) tapped delay line. The pulse compression using the matched filter gives a signal-to-noise ratio of 22 dB. Experimental results presented in this Paper demonstrate the ability of the system to increase the signal-to-noise ratio and the immunity to noise. The system may have a practical application in the ultrasonic non-destructive testing of absorbent materials.

关键词： barker code NDT pulse compression

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Spectral signatures and interference of 802.11 Wi-Fi signals with barker code spreading

Spectral signatures and interference of 802.11 Wi-Fi signals...

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1st IEEE International Symposium on New Frontiers in Dynamic Spectrum Access Networks

作者： Lee, T Al-Banna, A Zhou, XG LoCicero, J Ucci, D IIT Dept Elect & Comp Engn Chicago IL 60616 USA

ISBN: (纸本)1424400139

This paper characterizes interference in 802.11 Wireless Fidelity (Wi-Fi) systems that utilize barker codes as spreading sequences. Particularly, detailed spectral analyses are performed. These studies result in exact power spectral densities (PSDs) for 1 Mbps and 2 Mbps signaling schemes that define their spectral signatures. Investigation of the leakage of interference power into adjacent 802.11 channels, which can be useful for the deployment of cognitive radios, is presented. The theoretical and computer simulation results for the Wi-Fi signal PSDs are verified through experimental measurements and emulation.

关键词： 802. 11 PSD Wi-Fi spectral signature barker code

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Ultrasound strain imaging using barker code 7

Ultrasound strain imaging using Barker code

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7th International Conference on Electronics and Information Engineering (ICEIE)

作者： Peng, Hui Tie, Juhong Guo, Dequan Chengdu Univ Informat Technol Sch Software Engn Chengdu Peoples R China Chengdu Univ Informat Technol Sch Control Engn Chengdu Peoples R China

ISBN: (数字)9781510610811

ISBN: (纸本)9781510610811

Ultrasound strain imaging is showing promise as a new way of imaging soft tissue elasticity in order to help clinicians detect lesions or cancers in tissues. In this paper, barker code is applied to strain imaging to improve its quality. barker code as a coded excitation signal can be used to improve the echo signal-to-noise ratio (eSNR) in ultrasound imaging system. For the Baker code of length 13, the sidelobe level of the matched filter output is -22dB, which is unacceptable for ultrasound strain imaging, because high sidelobe level will cause high decorrelation noise. Instead of using the conventional matched filter, we use the Wiener filter to decode the barker-coded echo signal to suppress the range sidelobes. We also compare the performance of barker code and the conventional short pulse in simulation method. The simulation results demonstrate that the performance of the Wiener filter is much better than the matched filter, and Baker code achieves higher elastographic signal-to-noise ratio (SNRe) than the short pulse in low eSNR or great depth conditions due to the increased eSNR with it.

关键词： Strain imaging elasticity imaging barker code displacement estimate

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Bulk acoustic wave barker code sequence and the application in ultrasonic NDT

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Chinese Journal of Acoustics 1994年第3期13卷 219-223页

作者： BAI Yuhai and PEI Liwei (Institute of Acoustics, Academia Sinita. Beijing 100080 )

A simple and convcnient method to gain bulk acoustic wave barker code sequence is presented and the results of the correlation are givcn. The transducer response to a unit electric pulse is used as a unit code constituting the barker code sequence of acoustic signal. The phase precision of the code sequence as well as the fairly ideal response function are guaranteed by the high accuraey of a DATA-2020 Arbitrary Waveform Synthesizer and a DATA-6000 Universal Wavcform Analyzer. Some deviations between the experiments and thcory are caused by the transient response and timc delay characteristics of the ultrasonic tansducer.

关键词： barker code Correlation Ultrasonic NDT

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Phase code Integration Using Interpulse Techniques for Enhanced Radar Performance

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IEEE ACCESS 2025年 13卷 51680-51692页

作者： Ahmad, Basmah Butt, Faran Awais Naqvi, Ijaz Haider Ejaz, Saqib Ali, Saqib Muqaibel, Ali Hussein Alawsh, Saleh A. Anwar, Muhammad Arif Univ Management & Technol UMT Dept Elect Engn Lahore 54770 Pakistan King Fahd Univ Petr & Minerals KFUPM Ctr Commun Syst & Sensing Dhahran 31261 Saudi Arabia Lahore Univ Management Sci LUMS Dept Elect Engn Lahore 54792 Pakistan Ctr Excellence Sci & Appl Technol CESAT Islamabad 44000 Pakistan King Fahd Univ Petr & Minerals KFUPM Elect Engn Dept Dhahran 31261 Saudi Arabia

Phase coding plays an important role in radar systems, affecting signal modulation, target detection, and interference rejection. This study assesses various phase codes, including Gold, Kasami, barker, Frank, and Chaotic codes, by analyzing performance metrics like cross-correlation and peak-to-sidelobe ratio (PSLR). The study highlights certain limitations, suggesting the need for new waveform solutions. It integrates component-based and Kronecker product-based interpulse coding to combine different codes and improve overall system performance. By merging phase codes effectively, interpulse coding leverages the strengths of individual codes to produce a composite waveform with enhanced autocorrelation and cross-correlation properties, improving radar performance. An optimization problem is formulated using a weighted performance metric to identify the best waveform, considering factors such as cross-correlation and PSLR. The approach, utilizing simple Kronecker and element-wise multiplication techniques, offers significant benefits with minimal complexity. The barker-Gold interpulse code stands out as highly effective for spread spectrum-based applications due to its favorable correlation properties.

关键词： barker code cross-correlation gold code interpulse coding Kasami code Kronecker product peak-to-side-lobe ratio phase codes barker code cross-correlation gold code interpulse coding Kasami code Kronecker product peak-to-side-lobe ratio phase codes

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barker coded thermal wave imaging for defect detection in carbon fibre-reinforced plastics

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INSIGHT 2011年第11期53卷 621-624页

作者： Ghali, V. S. Panda, S. S. B. Mulaveesala, R. PDPM Indian Inst Informat Technol Design & Mfg Elect & Commun Engn Res Grp Infrared Imaging Lab Jabalpur India

Active thermal non-destructive testing (TNDT) methods utilise the acquired surface temperature profile over an object and subsequently process the obtained temperature data to detect surface or subsurface features of the object. This process, however, demands novel processing and excitation approaches to enhance the defect detectability with depth analysis. This contribution is intended to exhibit the detection capability of the recently introduced barker coded excitation for infrared imaging for characterisation of carbon fibre-reinforced plastic material. Experiments have been carried out for the proposed excitation scheme to study its defect detection capabilities.

关键词： Infrared non-destructive testing (IRNDT) carbon fibre-reinforced plastic (CFRP) barker code pulse compression Fourier transform

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Research on barker coded excitation method for magneto-acoustic imaging

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BIOMEDICAL SIGNAL PROCESSING AND CONTROL 2018年第0期39卷 169-176页

作者： Zhang, Shunqi Zhou, Xiaoqing Liu, Shikun Yin, Tao Liu, Zhipeng Chinese Acad Med Sci Inst Biomed Engn Tianjin 300192 Peoples R China Peking Union Med Coll Tianjin 300192 Peoples R China Chinese Acad Med Sci Neurosci Ctr Beijing 221116 Peoples R China

Functional imaging method of biological electrical characteristics based on magneto-acoustic effect gives valuable information of tissue in early tumor diagnosis. Common exciting and measuring method is to use single pulse. The imaging quality and the imaging speed are limited by the signal to noise ratio (SNR). In this study, we propose a processing method based on coded excitation and pulse compression to improve SNR of magneto-acoustic imaging. barker code is widely used in ultrasonic signal processing, which can effectively improve the signal to noise ratio. It is introduced to increase SNR of the magneto-acoustic signal. Simulations on magneto-acoustic signal and pulse compressed signal under barker coded excitation with a group of bit lengths are computed. Experiments on sample made of pork and graphite slices are done to validate the proposed coded excitation method. The pork sample is imaged to validate this method. SNR is investigated using barker codes with different bits. The results showed, the SNR of magneto-acoustic signal is improved by the coded excitation. When 13 bit barker code mode is adopted as the exciting signal, SNR improved by 21.5 dB. For a similar SNR improvement, the processing time of coded excitation method can be shortened by 95.8% compare with single pulse excitation method. In a conclusion, the coded excitation method is effective to improve the magneto-acoustic signal SNR and imaging quality. It also improves the magneto-acoustic imaging speed. (C) 2017 Published by Elsevier Ltd.

关键词： Magneto-acoustic imaging barker code Signal to noise ratio Compression

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An Adaptive Peak Detection Method for Inspection of Breakages in Long Rails by Using barker coded UGW

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IEEE ACCESS 2020年 8卷 48529-48542页

作者： Wei, Xiaoyuan Yang, Yuan Urena, Jesus Yan, Jiaxuan Wang, Haozhen Xian Univ Technol Dept Elect Engn Xian 710048 Peoples R China Shaanxi Key Lab Complex Syst Control & Intelligen Xian 710048 Peoples R China Univ Alcala Dept Elect Alcala De Henares 28805 Spain

For a broken rail detection system based on ultrasonic guided waves (UGW), the multimodal and dispersion of UGW degrade signal-to-noise ratio (SNR) and range resolution. To improve SNR of the received signals and range resolution, the pulse compression technique based on 13-bit barker code is presented in this work. Through a PSpice model of the pitch-catch setup, as well as performing field tests, it is shown that coded UGW signals can efficiently improve SNR by 5 dB and have strong noise immunity. As the detection distance increases, the mainlobe width increases linearly while the sidelobe peak levels remain basically unchanged. In addition, to correctly and quickly identify the corresponding transmissions at the receivers, an adaptive peak detection algorithm is proposed, which is based on a digital bandpass tracking filter, moving averaging filters and Hilbert transform. By using some field tests under different detection distances, it is found that compared to the previous works, the proposed adaptive peak detection algorithm has stronger robustness and better anti-noise performance. In addition, the proposed method is easy to integrate into a real-time detection system by proper software design.

关键词： Rails Signal to noise ratio Acoustics Ultrasonic transducers Encoding Transforms SPICE Peaks detection barker code pulse compression long rail breakages detection UGW

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