应用于水声MC-CDMA系统的一种自适应调制算法     

方荟  胡晓毅 《闽江学院学报》2012,33(2):73-76

自适应调制技术能有效地利用系统有限的功率和频谱资源,改善系统的误码率性能．针对资源受限的水声MC-CDMA系统提出一种自适应的调制算法．采用该方案的自适应水声MC-CDMA系统在获得有效频谱效率和分集增益的同时,还能获得很好的误码率性能．分析了提出的自适应调制算法的性能,并通过MATLAB系统仿真,表明自适应调制算法较非自适应调制可以使系统性能有明显的提高,说明了自适应调制技术在水声MC-CDMA中的有效性．  相似文献   

对称式微波功率传感器的幅度调制测量（英文）     

王德波  廖小平  田涛 《东南大学学报》2010,26(1):68-72

为了减小失配造成的测试误差,在测量调制信号的微波功率时提出了一种直流校正方法.在传感器左端输入微波功率,右端输入直流功率,微波功率存在的寄生损耗和电磁耦合造成了失配误差,而直流功率不存在失配误差,所以通过右端输入的直流功率可以校正左端微波功率的失配误差.测试了在不同调制率和调制深度的校正因子.测试结果表明,载波频率是造成幅度调制测试误差的主要因素,校正后载波频率和调制率对输出电压的影响很小,频率响应在20GHz范围内变得相对平滑,而且灵敏度平均提高了大约0.12mV/dBm.因此,该直流校正方法对于终端式微波功率传感器具有一定的参考意义.  相似文献   

In situ phase transitional polymeric vaccines for improved immunotherapy     

Jie Wang  Yi Wang  Shenglin Qiao  Muhetaerjiang Mamuti  Hongwei An  Hao Wang 《国家科学评论(英文版)》2022,9(2)

Cancer vaccines have exhibited immense potential in cancer treatment. Through activating the host''s immune system, vaccines stimulate extensive functional T cells to eliminate cancer. However, the therapeutic efficacy of cancer vaccines is limited by their inferior lymph node delivery and inadequate uptake of dendritic cells. Herein, we propose an in situ phase transitional strategy on vaccine manufacturing to maximally enhance lymph node drainage while ensuring adequate dendritic cell uptake. The phase transitional vaccines, with dynamic size modulation property, retain a small size (24.4 ± 3.1 nm) during lymph node draining then transform into larger particles (483.0 ± 41.6 nm) on-site by external signal input. Results show that this strategy induced rapid and robust immune response in a mouse melanoma tumor model. Furthermore, a stronger humoral immune response was observed in mice when immunized with MHC-II restricted antigen, which demonstrated that lymph node-targeted cancer vaccine delivery could be effectively manipulated through dynamic size modulation.  相似文献