本文讨论了空气隙型光固定衰减器的回波损耗。

This paper discusses the return loss in air-space type fixed optical attenuator.

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在海上进行探测水雷的试验中，常常因为船体的摇摆而使回波图像中目标的位置不固定，影响了水雷探测的准确性。

When we experiment on mine detection on the sea it is always found that the position of target in echo images is not fixed because of sway of ship and this reduces the veracity of detection.

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在天气回波信号谱宽固定的情况下，通过改变天气回波信号的平均多普勒频率，分析了回归滤波器对它的衰减情况。

Fixing the spectrum width of the weather echo signals, we change theirs mean Doppler frequency and filter them using regression filter. After filtering, we analyze the attenuation of them.

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