基于高斯包络调制激励的磁声信号频率分析
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摘要
本研究旨在探究基于高斯包络调制激励下,感应式磁声成像中磁声信号的频率特性。先使用4 MHz单正弦脉冲信号和中心频率为4 MHz的高斯包络调制信号,对不同电导率样本(铝、铜、锡)进行激励,使用中心频率为4 MHz的超声换能器进行接收,并对接收到的磁声信号进行频率分析。单脉冲激励方式造成磁声信号频率分析失准,基于高斯包络调制激励的磁声信号与激励信号频率一致。样本磁声信号与激励信号同频,且高斯包络调制激励方法使频率分析精度更高,频谱更为集中,更利于频域中信号特征的分析。
To explore the frequency characteristics of magneto-acoustic signals in induction magneto-acoustic imaging based on Gaussian envelope-modulation excitation. The 4 MHz single-sine pulse signal and the Gaussian envelope-modulated signal featuring a center frequency of 4 MHz were used to excite samples(aluminum, copper, tin) of different electrical conductivities, an ultrasonic transducer of the center frequency of 4 MHz was introduced as the receiver and then the received magneto-acoustic signals was analyzed. The single-pulse excitation mode resulted in a misaligned frequency analysis of magneto-acoustic signals, while the magneto-acoustic signals based on Gaussian envelope-modulation excitation were of the same frequency with the excitation signal.Sample′s magneto-acoustic signals are of the same frequency with excitation signals; moreover, the method of Gaussian envelope-modulation excitation realizes a higher precision of frequency analysis and a more centralized spectrum, for which it is more conducive to the analysis of frequency characteristics within a frequency domain.
To explore the frequency characteristics of magneto-acoustic signals in induction magneto-acoustic imaging based on Gaussian envelope-modulation excitation. The 4 MHz single-sine pulse signal and the Gaussian envelope-modulated signal featuring a center frequency of 4 MHz were used to excite samples(aluminum, copper, tin) of different electrical conductivities, an ultrasonic transducer of the center frequency of 4 MHz was introduced as the receiver and then the received magneto-acoustic signals was analyzed. The single-pulse excitation mode resulted in a misaligned frequency analysis of magneto-acoustic signals, while the magneto-acoustic signals based on Gaussian envelope-modulation excitation were of the same frequency with the excitation signal.Sample′s magneto-acoustic signals are of the same frequency with excitation signals; moreover, the method of Gaussian envelope-modulation excitation realizes a higher precision of frequency analysis and a more centralized spectrum, for which it is more conducive to the analysis of frequency characteristics within a frequency domain.
引文
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[11]程佩青.数字信号处理教程.第2版[M].清华大学出版社,2001.
[12]Ma Q,He B.Magnetoacoustic tomography with magnetic induction:a rigorous theory[J].IEEE Transactions on Biomedical Engineering,2008,55(2):813-816.
[2]Li X,Yu K,He B.Magnetoacoustic tomography with magnetic induction (MAT-MI) for imaging electrical conductivity of biological tissue:a tutorial review[J].Physics in Medicine & Biology,2016,61(18):R249.
[3]Roth B J,Basser P J,Wikswo J P.A theoretical model for magneto-acoustic imaging of bioelectric currents[J].IEEE Transactions on Biomedical Engineering,1994,41(8):723.
[4]Wen H,Shah J,Balaban R S.Hall effect imaging[J].IEEE Transactions on Biomedical Engineering,1998,45(1):119-124.
[5]Xu Y,He B.Magnetoacoustic tomography with magnetic induction (MAT-MI)[J].Physics in Medicine & Biology,2005,50(21):5175.
[6]刘志朋,马任,张顺起,等.磁声耦合声信号幅频特性的实验研究[J].生物医学工程研究,2013,32(1):1-6.
[7]Feng X,Gao F,Kishor R,et al.Coexisting and mixing phenomena of thermoacoustic and magnetoacoustic waves in water[J].Scientific Reports,2015,5:11489.
[8]Zhou X,Ma R,Zhang W,et al.Experimental study of the thermoacoustic effect in magnetoacoustic tomography[J].Aip Advances,2016,6(9):022902-675.
[9]李俊霖,周晓青,殷涛,等.注入式磁声成像中热声效应的初探[J].生物医学工程研究,2016,35(3):145-150.
[10]周晓青,刘世坤,张鑫山,等.热声效应对磁声信号的频率影响分析[J].医疗卫生装备,2018,39(1):41-45.
[11]程佩青.数字信号处理教程.第2版[M].清华大学出版社,2001.
[12]Ma Q,He B.Magnetoacoustic tomography with magnetic induction:a rigorous theory[J].IEEE Transactions on Biomedical Engineering,2008,55(2):813-816.