英文：Any of several devices that convert incident electromagnetic radiation of mixed frequencies to one or more discrete frequencies of highly amplified and coherent ultraviolet, visible, or infrared radiation.
英文：A device used to modulate an electromagnetic wave.
中文：调制器用以调制电磁波的装置
英文：An interconnected system for the distribution of electricity or electromagnetic signals over a wide area, especially a network of high-tension cables and power stations.
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