检索结果-南通市图书馆

Separating cyclostationary signals from spectrally overlapping interference

在线全文

学校读者我要写书评

暂无评论

Frontiers of Electrical and Electronic Engineering in China 2006年第3期1卷 307-312页

作者： GUO Jie LIU Yun YE Zhi-hui SONG Tie-cheng SHEN Lian-feng National Mobile Communications Research Laboratory Southeast UniversityNanjing 210096China

This paper studies an algorithm about separating spectrally overlapping signals using the cyclostationary properties of *** the basis of direct sequence spread system(DSSS),frequency shift filter is added into the re-ceiver of the communication *** the structure of frequency shift filter is more complicated than the time-domain filter,it uses both time correlations and fre-quency spectrum correlations so it can achieve better per-formances on separating the overlapping *** the analysis of cyclostationary characteristic and frequency spec-trum correlation,the structure of the frequency shift filter can be ***,a self-adaptive algorithm is utilized for the purpose of achieving optimum multidimensional tap weights of frequency shift *** simulation results indi-cate that this method can efficiently separate overlapping signals,and its error rate is lower than the time-domain filter or DSSS system by two orders of magnitude on the condition that high-power interference is added into the system.

关键词： cyclostationary frequency shift filter overlap signal spectral correlation

cyclostationary Model Based Multiple-Tone Interference Rejection in DSSS Communication Systems

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural Sciences 2002年第3期7卷 323-326页

作者： Gong Xiang\|yang, Hu Guang\|rui Department of Electronic Engineering, Shanghai Jiaotong University, Shanghai 200030, China Department of Electronic Engineering Shanghai Jiaotong University Shanghai China

Multiple-tone interference is a kind of narrow band interference appears in Direct Sequence (DS) Spread Spectrum (SS) communication system frequently that degrades the system performance. Most open literature studies on narrowband interference rejection assumed stationary SS signal and interference. SS signal and interference are modeled as cyclostationary and based on cyclostationary model, an interference rejection algorithm is proposed. Through computer simulation, it is shown that the performance of the SS system can be improved considerably after adopting this algorithm.

关键词： Key words spread spectrum interference rejection cyclostationary

cyclostationary MODEL IN DS SPREAD SPECTRUM COMMUNICATION SYSTEM

在线全文

学校读者我要写书评

暂无评论

Journal of Electronics(China) 2002年第2期19卷 172-174页

作者： Gong Xiangyang Hu Guangrui (Department of Electronic Engineering, Shanghai Jiaotong University, Shanghai 200030) Department of Electronic Engineering Shanghai Jiaotong University Shanghai

During the past research, Direct Sequence (DS) Spread Spectrum (SS) signal is modeled as stationary in most cases. cyclostationary model for SS signal is introduced in this letter. Compared with stationary model, cycl... 详细信息

关键词： cyclostationary Stationary Spread spectrum

A New Method for Rolling Element Bearing Fault Diagnosis Based on cyclostationary Theory

在线全文

学校读者我要写书评

暂无评论

International Journal of Plant Engineering and Management 2001年第3期6卷 136-142页

作者： JIANG Ming, CHEN Jin, QIN Kai The State Key Laboratory of Vibration, Shock & Noise, Shanghai Jiaotong University, Shanghai 200030, P.R.China The State Key Laboratory of Vibration Shock & Noise Shanghai Jiaotong University Shanghai 200030 P. R. China

The theory of cyclostationary and its application are very important for the analysis and processing of a non stationary signal. The paper introduces second order cyclostationary statistics, with emphass on discussion of cyclic periodogram arithmetic. Comparing the time smoothed cyclic periodogram with the frequency smoothed cyclic periodogram, we found that the former is more useful to extract the feature of cyclostationary signals. The method has been applied to analyze the vibration signal of a rolling element bearing measured on a test bench, and proved to be effective. Meanwhile, we have compared it with traditional power spectral density analysis, and the results prove that the time smoothed cyclic periodogram is more available to diagnose the fault of a rolling element bearing.

关键词： fault diagnosis cyclostationary signal processing

NONPARAMETRIC POLYSPECTRAL ESTIMATORS FOR k-TH-ORDER (ALMOST) cyclostationary COMPLEX PROCESSES

在线全文

学校读者我要写书评

暂无评论

Journal of Electronics(China) 1998年第1期15卷 9-15页

作者： Mao Yongcai Bao Zheng(Key Laboratory for Radar Signal Processing, Xidian University, Xi’an 710071) Key Laboratory for Radar Signal Processing Xidian University Xi’an

Higher-order almost cyclostationary complex processes are complex random signals with almost periodically time-varying statistics, which is important to the research of non-Gaussian signals in information system. In tins paper, smoothed polyperiodograms are proposed for related to cyclic polyspectral estimation and are shown to be consistent and asymptotically complex normal. Asymptotic covariance expressions are derived along with their computable forms.

关键词： Complex cyclostationary sequences Nonparametric cyclic-polyspectrum estima-tion Asymptotic statistical performance

Throughput Estimation with Noise Uncertainty for cyclostationary Feature Detector in Cognitive Radio Network

在线全文

学校读者我要写书评

暂无评论

Wireless Engineering and Technology 2015年第2期6卷 25-32页

作者： Mohsen M. Tantawy National Telecommunication Institute Cairo Egypt

Cognitive Radio Networks (CRNs) are recognized as the enabling technology for improving the future bandwidth utilization. In CRNs secondary users are allowed to utilize the frequency bands of primary users when these bands are not currently being used. The secondary users are required to sense the radio frequency environment. The lower the probability of false alarm, the more chances the channel can be reused and the higher the achievable throughput for the secondary network. The main contribution of this paper is to formulate the sensing-throughput-noise uncertainty tradeoff for cyclostationary feature detection. Computer simulations have shown that for a 1 MHz channel, when the sensing duration is 2% of total time, the spectrum will get 99% probability of detection regardless of 50% noise uncertainty.

关键词： Cognitive Radio Network cyclostationary Feature Detector Throughput Noise Uncertainty

PERFORMANCE ANALYSIS OF SECOND-ORDER STATISTICS FOR cyclostationary SIGNALS

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2002年第2期7卷 158-161页

作者： JIANG Ming(姜鸣) CHEN Jin(陈进) State Key Lab. of Vibration Shock & Noise Shanghai Jiaotong Univ. Shanghai 200030 China State Key Lab. of Vibration Shock & Noise Shanghai Jiaotong Univ. Shanghai 200030 China

The second order statistics for cyclostationary signals were introduced, and their performance were discussed. It especially researched the time lag characteristic of the cyclic autocorrelation function and spectral correlation characteristic of spectral correlation density function. It was pointed out that those functions can be available to extract the time vary information of the kind of non stationary signals. Using the relations of time lag cyclic frequency and frequency cyclic frequency independently, vibration signals of a rolling element bearing measured on test bed were analyzed. The results indicate that the second order cyclostationary statistics might provide a powerful tool for the feature extracting and fault diagnosis of rolling element bearing.

关键词： fault diagnosis cyclostationary signal signal processing

NONPARAMETRIC SPECTRAL ESTIMATORS FORSECOND-ORDER (ALMOST) cyclostationaryCOMPLEX PROCESSES

在线全文

学校读者我要写书评

暂无评论

Journal of Electronics(China) 1997年第1期14卷 12-19页

作者： Mao Yongcai Bao Zheng(Laboratory for Radar Signal Processing, Xidian University, Xi’an, 710071) Laboratory for Radar Signal Processing Xidian University Xi’an

Second-order almost cycloststionary complex processes are complex random signals with almost periodically time-varying statistics. Smoothed periodograms are proposed for related to cyclic spectral estimation and are s... 详细信息

关键词： Nonstationary spectral analysis Complex cyclostationary sequences Nonpara-metric cyclic-spectrum estimation Consistency Asymptotic covariance

Fault Feature Extraction of Rolling Bearing Based on an Improved Cyclical Spectrum Density Method

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2015年第6期28卷 1240-1247页

作者： LI Min YANG Jianhong WANG Xiaojing School of Mechanical Engineering University of Science and Technology Beijing

The traditional cyclical spectrum density（CSD） method is widely used to analyze the fault signals of rolling bearing. All modulation frequencies are demodulated in the cyclic frequency spectrum. Consequently, recognizing bearing fault type is difficult. Therefore, a new CSD method based on kurtosis（CSDK） is proposed. The kurtosis value of each cyclic frequency is used to measure the modulation capability of cyclic frequency. When the kurtosis value is large, the modulation capability is strong. Thus, the kurtosis value is regarded as the weight coefficient to accumulate all cyclic frequencies to extract fault features. Compared with the traditional method, CSDK can reduce the interference of harmonic frequency in fault frequency, which makes fault characteristics distinct from background noise. To validate the effectiveness of the method, experiments are performed on the simulation signal, the fault signal of the bearing outer race in the test bed, and the signal gathered from the bearing of the blast furnace belt cylinder. Experimental results show that the CSDK is better than the resonance demodulation method and the CSD in extracting fault features and recognizing degradation trends. The proposed method provides a new solution to fault diagnosis in bearings.

关键词： cyclostationary cyclical spectrum density rolling bearing fault diagnosis