Digital communication using multiple - input - multiple - output ( mimo ) has recently emerged as one of the most significant technical breakthroughs in modern communications . with multiple antennas both at the transmitter and receiver , mimo can increase the system capacity and the spectrum efficiency a lot at no cost of extra spectrum Mimo系统能够充分开发空间资源,它利用多天线实现多发多收,在不增加频谱资源和天线发射功率的情况下,可以成倍地提高信道的容量和频谱利用率,同时提高信道的可靠性、降低误码率。
The technical breakthroughs in growth of nd : cngg had been made . in particular , continuous laser operation was achieved from nd : cngg pumped by ld . when the crystal wafer was end - pumped by one bar of ld with 807nm wavelength , the cw laser output power of 123 . 1 mw was obtained with slope efficiency of 22 . 3 % 本论文用自动化熔体提拉技术成功生长出< 111 >方向的直径25mm以上,长度80mm以上的平界面无核心nd : cngg单晶,确定了晶体结构和物相,测量了晶体的光谱性能,晶体消光比达到34db ,晶体生长技术有新的突破,实现了连续激光运转,用单支807nm半导体激光二极管端面泵浦该晶体片子,在国内首次获得123 . 1mw的1 . 062 m连续激光输出,斜效率达22 . 3 % 。
