检索结果-南通市图书馆

Flexible and Accurate Frequency Estimation for Complex Sinusoid Signal by Interpolation Using DFT Samples

Chinese Journal of Electronics 2018年第1期27卷 109-114页

作者： XIANG Jinzhi CUI Wei SHEN Qing School of Information and Electronics Beijing Institute of Technology

A flexible and accurate frequency estimator is first proposed for frequency estimation of a complex sinusoid weighted with a rectangular window function in additive white Gaussian noise. This proposed frequency estimator can be operated in the application of an arbitrary length discrete Fourier transform where the original input data is padded with any zeroes, which makes it more flexible in practice. The proposed frequency estimator utilizes the maximum sample value and its two adjacent samples in the frequency domain to perform the fine frequency estimation with unbiased results obtained. Then a modified frequency estimator is proposed to estimate the frequency when the complex sinusoid signal is weighted with different nonrectangular window functions. Although the modified frequency estimator is nonanalytic and biased, it can still improve the estimation performance for certain applications. Simulation results demonstrate that both of the proposed frequency estimators are effective to achieve the high frequency estimation accuracy. And the root mean square errors of the proposed frequency estimators approach the Cramer-Rao bound when the signal-to-noise ratio is large enough to make the coarse frequency estimation work effectively.

关键词： Frequency estimation Complex sinusoid DFT interpolation zero-padding

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Edge Effect Correction in the S-A Method for Geochemical Anomaly Separation

引用

Journal of China University of Geosciences 2004年第4期15卷 379-387页

作者： Ge Yong Department of Earth and Atmospheric Science, York University, Toronto, ON, M3J 1P3, Canada State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences & Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China Cheng Qiuming Department of Earth and Atmospheric Science, York University, Toronto, ON, M3J 1P3, Canada Earth Systems and Mineral Resource Engineering Lab, China University of Geosciences, Wuhan 430074, China Zhang Shenyuan Department of Earth and Atmospheric Science, York University, Toronto, ON, M3J 1P3, Canada Department of Resource and Earth Science, China University of Mining & Technology, Beijing 100083, China Department of Earth and Atmospheric Science York University Toronto ON M3J 1P3 Canada State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences & Natural Resources Research Chinese Academy of SciencesBeijing 100101China Department of Earth and Atmospheric Science York University Toronto ON M3J 1P3 Canada Earth Systems and Mineral Resource Engineering Lab China University of Geosciences Wuhan 430074 China Department of Earth and Atmospheric Science York University Toronto ON M3J 1P3 Canada Department of Resource and Earth Science China University of Mining & Technology Beijing 100083 China

Anomaly separation using geochemical data often involves operations in the frequency domain, such as filtering and reducing noise/signal ratios. Unfortunately, the abrupt edge truncation of an image along edges and holes (with missing data) often causes frequency distribution distortion in the frequency domain. For example, bright strips are commonly seen in frequency distribution when using a Fourier transform. Such edge effect distortion may affect information extraction results; sometimes severely, depending on the edge abruptness of the image. Traditionally, edge effects are reduced by smoothing the image boundary prior to applying a Fourier transform. zero-padding is one of the most commonly used smoothing methods. This simple method can reduce the edge effect to some degree but still distorts the image in some cases. Moreover, due to the complexity of geoscience images, which can include irregular shapes and holes with missing data, zero-padding does not always give satisfactory results. This paper proposes the use of decay functions to handle edge effects when extracting information from geoscience images. As an application, this method has been used in a newly developed multifractal method (S-A) for separating geochemical anomalies from background patterns. A geochemical dataset chosen from a mineral district in Nova Scotia, Canada was used to validate the method.

关键词： edge effect correction fractal modeling spatial information extraction zero-padding decay functions.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

ZP-CI/OFDM:A Power Efficient Wireless Transmission Technology

引用

ZTE Communications 2011年第1期9卷 45-48页

作者： Pei Gao Xiaohu Chen Jun Wang National Key Laboratory of Science and Technology on Communications the University of Electronic Science and Technology of China

Low power efficiency is a deficiency in traditional Orthogonal Frequency Division Multiplexing （OFDM） systems. To counter this problem, a new wireless transmission technology based on zero-padding Carrier Interferometry OFDM （ZP-CI/OFDM） is proposed. In a ZP-CI/OFDM system, transmission symbols are spread to all OFDM subcarriers via carrier interferometry codes. This reduces the Peak-to-Average Power Ratio （PAPR） that traditional OFDM suffers and also exploits frequency diversity gain. By zero-padding at the transmitter, advanced receiver technologies can be adopted for ZP-CI/OFDM so that frequency diversity gain can be further utilized and the power efficiency of the system is improved.

关键词： power efficiency carrier interferometry orthogonal frequency division multiplex zero-padding frequency diversity gain

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：