The static frequency modulation characteristic of electric network is the foundation of frequency stability of the electric network that determined by frequency modulation.

由一次调频决定的电网静态调频特性，则是电网频率稳定性的基础。

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First, the generation mechanism, components and frequency characteristic of radiated noise of naval ships are studied. There exists periodical modulation for the amplitude of propeller noise.

首先讨论了舰船辐射噪声的产生机理、构成和频率特性，指出螺旋桨噪声的振幅存在周期性调制。

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The radar controller is then arranged to modify a given modulation pattern in dependence on the characteristic frequency of the signal being modulated.

雷达控制器则设置成根据被调制的信号的特征频率修改给定的调制图案。

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