摘要
根据电磁层析成像系统中的激励磁场与待测物场之间的畸变场作用是非线性的,检测信号不能单纯被认为是待测物体在敏感场中响应的线性叠加,而且不同的检测信号在激励过程中的不同方向上有着各自的相位幅值变化。作者结合传统的EMT系统设计了使用直接式数字频率合成器来对检测信号的相位、幅值变化进行实时解调的方案。结果表明该方案的准确度和可靠性高,稳定性好,有效改善了原有系统中的相位幅值偏差。
According to the nonlinear interaction of distortion field which is between excitation field and measured field in the existing electromagnetic tomography system, and the condition that the detection signal can＇t be simply considered as a linear superposition in the sensitive field. Combined with the the traditional Electromagnetic Tomography （EMT） system,above all,the paper designs a quadrature demodulator that is using direct digital synthesizers,and gets the output of the detection signal by adjusting the demodulating vector.Then,on the base of hardware system design,combined with image algorithm,the image reconstruction has been realized.Four kinds of experiment results showed that the quadrature demodulator designed possesses a high detection resolution and reliability as well as good stability, and improves phase and amplitude deviation of the original system effectively.
出处
《现代科学仪器》
2014年第2期70-73,共4页
Modern Scientific Instruments
