星座符号

改进算法充分利用了十字型QAM信号星座的符号统计特性，使误差模型与十字型星座更加匹配，能够获得更优的稳态性能。

The modified algorithm uses fully the symbol statistical characteristics of cross QAM signals , acquiring an improved performance due to much better match between error models and cross constellations .

该方法能够有效地将相邻载波的星座点符号间欧氏距离增大，从而使认知用户相邻载波产生的干扰互相抵消，达到减小认知用户对授权用户干扰的目的。

This method can effectively increase the Euclidean distance between the symbols on the adjacent carriers , so that the interference caused by the adjacent carriers would cancel each other in some way .

研究表明，星座图与符号率联合控制的自适应调制系统，在具备单纯星座可调的自适应调制系统优点的同时，还改善了这种调制方式在动态范围和延时免疫力方面的缺陷。

The adaptive modulation system with symbol rate and level adjustable has the adventages of that with QAM constellation adjustable , and furthermore its peroformance improves greatly with respect to the dynamic range and delay immunity .

全数字多星座图、可变符号率QAM调制器

An All-Digitized Multimode and Variable Symbol Rate QAM Modulator FIGURE

假设采用等概率中心对称星座调制导频符号，我们证明不仅加性白高斯噪声会给估计带来干扰，由多普勒扩展引起的载波间干扰也会引起偏差。

Assuming the equiprobable centro-symmetric constellation for modulation , SFCM was proved to be biased due not only to the noise , but also to the irreducible inter-carrier interference aroused by the Doppler spread .