In modern shortwave communication systems, the channels are mostly frequency-selective, multipath transmission causes the coherent attenuation and symbol interference.

现代短波通信系统，其信道大多数具有频率的选择性，多径传输产生了信号的相干衰落与符号干扰。

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A new optical attenuation standard device developing based on coherent detection principle is presented.

介绍了一种新的建立在相干检测原理上的光衰减标准。

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Results showed that the jet flow length, concentration and anti-attenuation of coherent jet oxygen lance were better than that of common oxygen lance.

结果表明，集束射流氧枪比普通超音速氧枪射流长，射流集中、衰减慢。

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