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在许多情况下,到达水听器的声波有入射波也有反射波,两者在时间上重合在一起,无法分开,水听器的输出自然为入射波与反射波迭加的结果。这时可用两个小型水听器分别求出入射波和反射波。 设在水中以距离d放置两个小型水听器M_1,M_2,对两水听器的输出进行付里叶变换,分别为m_1(ω),m_2(ω)。设两水听器的输出信号在延迟时间τ(τ=d/c,c为声速)以后其付里叶变换分别为m_1′(ω),m_2′(ω),则水听器M_1接收的入射波和反射波信号的付里叶变换P_1(ω),P_r(ω)可表示如下:
In many cases, the sound waves arriving at the hydrophone have incident and reflected waves, which coincide in time and can not be separated. The output of the hydrophone naturally results from the superimposition of the incident and reflected waves. At this time, two small hydrophone can be used to find the incident and reflected waves respectively. Set in the water to place two small hydrophone M_1, M_2 at a distance d, the two hydrophone output Fourier transform, respectively, m_1 (ω), m_2 (ω). Let the output signal of the two hydrophone be the Fourier transform of m_1 ’(ω) and m_2’ (ω) respectively after the delay time τ (τ = d / c, c is the sound velocity) The Fourier transforms P_1 (ω) and P_r (ω) of the incident and reflected signals can be expressed as follows: