The Fourier amplitude spectrum used in a seismological model can be expressed as a product of source spectrum, propagation path factor and site effect in frequency domain.

在频域内，场地的地震动傅立叶幅值谱，可以表示为震源谱、传播路径影响因子和场地效应的乘积。

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The spectrum division technique was used for establishing signal model of delay time measurement, and amplitude frequency characteristics of the signal after spectrum division was investigated.

利用频谱相除技术构建了延迟时间测量的信号模型，研究了频谱相除后信号的幅频特性。

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Spectrum of the amplitude-modulated wave is observed by a radio frequency spectrum analyzer and amplitude values of every spectrum are recorded at the upper sideband or lower sideband.

用射频频谱分析仪观测一个已调波的频谱成分，记录上边带或下边带中各条谱线的幅度值，从而可以根据有关算式计算出调制信号（音频信号）的失真度。

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