In order to avoid spectrum error due to energy leakage , the thesis research on identification of parameters of two close frequency components in discrete spectrum analysis , and simulation result shows the validity of the method 针对由于能量泄漏造成的频谱误差，深入研究了密集频谱的频域参数识别法，从理论上加以推导，并通过仿真证明了该方法的有效性，可以识别1个频率分辨率以内的两临近频率分量。
In order to simplify the output spectrum analysis of dds , we build a dds simulation platform . the results of simulation proved that the optimizing methods we used are very useful , and an improvement about 30 db was got in the dds digital output spectrum 同时，搭建了dds仿真平台，使得对dds频谱的分析大为简化，并进行了大量的仿真分析，证实了所采用的优化设计方法对输出信号数字谱的改善达到了30db以上。
2 . methods in frequency domain : through a comparative study , wedge and ring feature of fourier transform performs better than other features based on texture spectrum . it represents the directivity , coarseness and regularity of an image 在基于频率域的纹理分析方法中，分析了基于傅立叶变换的纹理分析方法，经两组对比实验，楔环特征能够很好的反映图象纹理的方向性、粗糙性和规律性，在检索中明显优于基于频谱的简单统计特征。
Our main work is as following : ( 1 ) research many methods to estimate blur parameter , carefully analyze the blur function of straight line motion with constant velocity , put forward a method to estimate blur parameters by zero value points according to the blurred images " spectrum 主要工作如下： ( 1 )研究了多种估计退化参数的方法，并仔细分析了匀速直线运动模糊图像的退化函数，根据其频谱的特点提出了用零值点方法来估计退化参数。
Power spectrum parameters , such as the power spectrum dc component . gamma . , half power bandwidth bw and average power . psi . w are transformed to . gamma . , an equivalent half power bandwidth be and an equivalent average power . psi . e , where be is a predetermined constant 频率轴参数如频谱的直流部份、平均能量、以及半能量频宽等，可以利用本发明所提出之架构将其转换、等效平均能量、以及等效半能量频宽，其中等效半能量频宽的值是一个给定的常数。
Along with the development of the technology of the wireless communication particular the modern modulation and software radio technique , meantime the employ of wireless frequency are more presser , the development of the receiver tend towards high performance and high integration 随着无线通信技术特别是现代调制体制和软件无线电技术的快速发展,且无线频谱的拥挤程度日益加剧,无线电接收机在设计和实现上越来越趋向于高性能、高集成度方向。
Especially , in the solution of pulse spectrum , the negative frequency form of nls equation should be solved by the negative frequency form of fourier transformation , while the positive frequency form of nls equation is solved by the positive frequency form of fourier transformation 尤其在脉冲频谱的求解问题中，如果采用负频形式的非线性薛定谔方程则必须选取负频形式的傅里叶变换；如果采用正频形式的非线性薛定谔方程则必须选取正频形式的傅里叶变换。
The method of compressing bandwidth of fringe function is proposed that basis fringe contains discrete spectrum which is based on human vision for real - time display , we also introduce discusses the spatial light modulators ( slms ) based on display system of digital holography and theory of numerical reconstruction of digital holography 为了达到实时性要求，在满足人眼视觉的光信息量基础上，对带宽压缩的理论问题进行了研究，提出了基于离散频谱的带宽压缩算法，并给出了结果。
This article takes hanging off and wide fluctuation of transmition velocity of adsl as example , then analysis centers on the discerte multiple tone and the principle of channel load assignation . from analysis above article points out the root of adsl being sensible of noise signal . at last , reserches effects that window function and barrier effect on frequency and adopts fft to work out the noise power of adsl 本文以电信现在推出的adsl传输中链路经常掉线和传输速率经常大范围波动为例，重点分析了adsl所使用的dmt调制方式和注水算法分配信道载荷方式原理，由此指出adsl对噪声信号敏感的根源，在得到问题的根源之后，分析了窗函数和栅栏效应对频谱的影响，采用fft方法计算adsl线路的噪声功率谱，为adsl线路测试提供了可靠的理论依据。
