QAM at a fixed point-to-point digital microwave systs in the wider application, it has a very highfrequencyspectrum utilization.
QAM在固定的点对点数字微波系统中应用较广泛，它具有很高的频谱利用率。
2
Photovoltaic cells are usually most responsive to photons in the visible and ultraviolet parts of the spectrum, but they can also respond to high-frequency infrared photons.
光伏电池通常对光谱中的可见光和紫外线波段的光子受激性最好，但高频红外光子也能激发电流。
3
The next generation mobile communication 4g called will support very high data transmission rate. It's necessary to introduce technology with highfrequency utilization in limited frequency spectrum.