Based on analysis of synchronization techniques in ofdm , this dissertation present a ml arithmetic to estimate time and frequency offset using symmetrical & conjugate prefix . the correlation peak of likelihood function curve is very sharp according this arithmetic , so the symbol synchronization by this arithmetic is exacter than that by general arithmetic using cycle prefix 文中在全面分析ofdm同步技术的基础上,提出了利用对称共轭前缀的最大似然估计法来进行符号定时和频偏估计,相对于传统的利用循环前缀的最大似然算法,这里提出的算法可以获得尖锐的相关图样,定时精度高,频偏估计误差小。
This thesis mainly discusses the techniques of channel estimation in frequency domain , which utilizes the optimized leading sequence . an enhanced method for searching optimized leading sequences is introduced based on existing documents . this method can decrease the errors and make the searching and caculating easier 本论文主要讨论用最佳前导序列在频域中进行信道估计的问题，在前人的基础上提出一种改进型的搜索最佳前导序列的方法，可使得估计误差减小且便于搜索计算，仿真验证了算法的有效性。
And key technologies of mc - cdma , channel estimations and diversity combinations , are mainly studied for the application of mc - cdma . the channel estimation based on pilot carriers is analyzed , and an improved method with wiener filtering is presented . simulations of the method are carried in time - varying multi - path channel 本文分析了基于导频的信道估计算法，提出了采用维纳滤波平滑的改进估计算法，并在多径时变信道下进行了计算机仿真，对系统各参数分别对信道估计误差和误码率性能的影响做了详细分析和比较，从而证明了算法和改进的有效性。
To solve the problem of filtering divergence in the case of low observability and large estimating error to the target ’ s original state in the ssbopls , this thesis presents a two - stage multiple mode extended kalman filtering ( ekf ) algorithm . at the beginning of filtering , system often has large estimating error . in order to efficiently avoid filtering divergence , the algorithm uses a mode - set which contains multiple modes to approach the real target state mode 在估计误差比较大的滤波初始阶段,采用多个模型组成的模型集合加权来逼近目标的真实状态模型,可以有效地减小滤波的模型误差,避免滤波的发散;当滤波达到稳态后,改为采用单模型滤波以节省计算量和系统存储量。
When filtering comes to steady - state , a single mode is applied in the algorithm to reduce the calculation complexity and the system storage . simulation results indicate that the locating accuracy of the algorithm is similar to that of ekf when the original estimation is accurate . when the system has large original state estimating error , the proposed algorithm can still accurately track the target while ekf diverges 仿真结果表明,在初始状态估计比较精确的情况下,该算法定位精度与经典扩展卡尔曼滤波算法相当;在初始状态估计误差较大的情况下,采用经典扩展卡尔曼滤波算法滤波极易发散,而采用本文算法在保持较高定位精度的同时,可以快速收敛。
Thereafter , the rfq - pcr method for the detection and enumeration of s . costatum cells is established with primer6 ( f / r ) and taqman6 . the regression curve for enumeration is delineated according to the development of the fluorescent densities in the rfq - pcr with the increasing number of s . costatum cells . the regression equation is y = - 3 . 3427x + 43 . 443 , in which x indicates the log10 of cell number , and y indicates the ct values , with r2 of 0 . 9788 以rfq一pcr中实际细胞数的常用对数值为横座标，以测得的ct值为纵座标，绘制出了定量检测的标准曲线，该曲线的回归方程为: y =一3 . 3427x + 43 . 443 ，其相关系数是: rz二0 . 9788 ， ct值的标准估计误差为sy ’ x二0 . 6741 。
