Spread spectrum signals are now widely used for secure communications, as well as for multiple access interference (MAI). They have many interesting properties, including low probability of interception. Indeed, DS/SS transmitters use a periodical pseudo-random sequence to modulate the baseband signal before transmission. A receiver which does not know the sequence can not demodulate the signal. Blind estimation of m-sequence is only discussed openly in the situation without multi-path interference and MAI so far. In this paper, we use the independent component analysis (ICA) to separate the data bits transmitted by different users in multi-path, and then identify m-sequence according to the triple correlation function (TCF) of m-sequence. The performance of this blind estimation is analyzed under Gaussian noise. Illustrative simulation examples are provided at last.
{"title":"Blind Estimation of the Pseudo-random Sequences of Direct Sequence Spread Spectrum Signals in Multi-Path Using Fast ICA","authors":"L. Shen, Zhijin Zhao","doi":"10.1109/PACCS.2009.75","DOIUrl":"https://doi.org/10.1109/PACCS.2009.75","url":null,"abstract":"Spread spectrum signals are now widely used for secure communications, as well as for multiple access interference (MAI). They have many interesting properties, including low probability of interception. Indeed, DS/SS transmitters use a periodical pseudo-random sequence to modulate the baseband signal before transmission. A receiver which does not know the sequence can not demodulate the signal. Blind estimation of m-sequence is only discussed openly in the situation without multi-path interference and MAI so far. In this paper, we use the independent component analysis (ICA) to separate the data bits transmitted by different users in multi-path, and then identify m-sequence according to the triple correlation function (TCF) of m-sequence. The performance of this blind estimation is analyzed under Gaussian noise. Illustrative simulation examples are provided at last.","PeriodicalId":320447,"journal":{"name":"Pacific-Asia Conference on Circuits, Communications and Systems","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122111081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Using primary components and factor analysis (PCFA) and its advantages, the mobile learning terminal (MLT) and its evaluation standard are analyzed. Based on PCFA model and the scores by experts, the analysis results are computed reflecting main function indexes of evaluation standard in MLT. Through case study, it can be seen that some indexes (standards) play very important role in analyzing and assessing main function indexes and all the evaluation standards should be considered because evaluation standard in MLT depends on the interaction. Through analysis and deduction, it is concluded that, under the premise of minimizing the data loss, the application of PCFA in assessing evaluation standard in MLT approved to be practicable.
{"title":"Investigation of Primary Components and Factor Analysis in Assessing MLT Standard","authors":"Zhiming Qu, Ke Sun","doi":"10.1109/PACCS.2009.20","DOIUrl":"https://doi.org/10.1109/PACCS.2009.20","url":null,"abstract":"Using primary components and factor analysis (PCFA) and its advantages, the mobile learning terminal (MLT) and its evaluation standard are analyzed. Based on PCFA model and the scores by experts, the analysis results are computed reflecting main function indexes of evaluation standard in MLT. Through case study, it can be seen that some indexes (standards) play very important role in analyzing and assessing main function indexes and all the evaluation standards should be considered because evaluation standard in MLT depends on the interaction. Through analysis and deduction, it is concluded that, under the premise of minimizing the data loss, the application of PCFA in assessing evaluation standard in MLT approved to be practicable.","PeriodicalId":320447,"journal":{"name":"Pacific-Asia Conference on Circuits, Communications and Systems","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123393611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Generator paralleling is a frequent and essential operation in the power system. If the frequency error is too great, the oncoming generator could slip a pole, causing damage to the machine. Therefore, the precision frequency measurement of the generator and the power system is one of important conditions to ensure that the automatic quasi-synchronizer can operate accurately. A new method of frequency measurement used in the generator automatic quasi-synchronizer is discussed in this paper. The basic principle of the frequency measurement is introduced. The frequency measurement is finished by combining PIC16F877 and FPGA (Field-Programmable Gate Array) technique. The hardware and software designs were introduced. The device adopted PIC16F877 as main controller and FPGA as assistant controller which detects the frequency and the PIC16F877 manages the data and implements intelligent control. The excellence of the mix design is that two advantages are reinforced. The hardware circuit is simple and the reliability of the system is high, so that the generator realizes quasi-synchronizing quickly and veracity.
{"title":"Frequency Measurement of the Automatic Generator Quasi-synchronizer Based on PIC16F877 and FPGA","authors":"Xiaoying Zhang, Cunlu Dang, Defu Wang","doi":"10.1109/PACCS.2009.42","DOIUrl":"https://doi.org/10.1109/PACCS.2009.42","url":null,"abstract":"Generator paralleling is a frequent and essential operation in the power system. If the frequency error is too great, the oncoming generator could slip a pole, causing damage to the machine. Therefore, the precision frequency measurement of the generator and the power system is one of important conditions to ensure that the automatic quasi-synchronizer can operate accurately. A new method of frequency measurement used in the generator automatic quasi-synchronizer is discussed in this paper. The basic principle of the frequency measurement is introduced. The frequency measurement is finished by combining PIC16F877 and FPGA (Field-Programmable Gate Array) technique. The hardware and software designs were introduced. The device adopted PIC16F877 as main controller and FPGA as assistant controller which detects the frequency and the PIC16F877 manages the data and implements intelligent control. The excellence of the mix design is that two advantages are reinforced. The hardware circuit is simple and the reliability of the system is high, so that the generator realizes quasi-synchronizing quickly and veracity.","PeriodicalId":320447,"journal":{"name":"Pacific-Asia Conference on Circuits, Communications and Systems","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115259990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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