Physical meaning: the self-correlation function and the energy spectrum density function compose a Fourier transform pair.
物理含义：能量信号的自相关函数与能量谱密度函数构成傅立叶变换对。
2
By using the Fourier transform, the problem can be solved with a pair of dual integral equations in which the unknown variable is the jump of displacements across the crack surfaces.
首先利用付里叶变换，使问题的求解转换成对一对变量为裂纹面上位移差的对偶积分方程的求解。
3
Relationship between the target scattering function and the echo signal is deduced to hold as a Fourier transform pair by analyzing the texture of echo signal for a passive radar imaging system;