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Search Results: 1 - 10 of 39 matches for " BOC "
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Solvent-Free Mechanochemical Deprotection of N-Boc Group  [PDF]
Davor Margeti?, Mateja ?ud
International Journal of Organic Chemistry (IJOC) , 2017, DOI: 10.4236/ijoc.2017.72011
Abstract: Boc protection group could be readily removed in a very mild mechanochemical conditions. In a short reaction time, ball milling of Boc-protected amines with p-toluenesulfonic acid in solvent-free conditions affords corresponding amine p-TsOH salts.
Research on Blanket Jamming to Beidou Navigation Signals Based on BOC Modulation  [PDF]
Pei Wang, Xiaochun Lu, Rui Wang
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2016, DOI: 10.4236/ijcns.2016.95012
Abstract: Aiming at the issue of influence of blanket jamming on performances of Beidou navigation signals, through studying Beidou signals based on the BOC modulation technology, establishing a blanket jamming mathematical model, and performing modeling and simulation on multiple jamming technologies, to attain the jamming curves of time domains and frequency domains of Beidou signals, and the correlation curve of the signal-to-jamming rate and the bit error rate under blanket jamming, and thus realizing evaluation on the jamming performance.
Cross-Correlation-Function-Based Multipath Mitigation Method for Sine-BOC Signals
H. H. Chen,W. M. Jia,M. L. Yao
Radioengineering , 2012,
Abstract: Global Navigation Satellite Systems (GNSS) positioning accuracy indoor and urban canyons environments are greatly affected by multipath due to distortions in its autocorrelation function. In this paper, a cross-correlation function between the received sine phased Binary Offset Carrier (sine-BOC) modulation signal and the local signal is studied firstly, and a new multipath mitigation method based on cross-correlation function for sine-BOC signal is proposed. This method is implemented to create a cross-correlation function by designing the modulated symbols of the local signal. The theoretical analysis and simulation results indicate that the proposed method exhibits better multipath mitigation performance compared with the traditional Double Delta Correlator (DDC) techniques, especially the medium/long delay multipath signals, and it is also convenient and flexible to implement by using only one correlator, which is the case of low-cost mass-market receivers.
Linear-Combined-Code-Based Unambiguous Code Discriminator Design for Multipath Mitigation in GNSS Receivers
Jiawei Ren,Huihua Chen,Weimin Jia,Minli Yao
Radioengineering , 2012,
Abstract: Unambiguous tracking and multipath mitigation for Binary Offset Carrier (BOC) signals are two important requirements of modern Global Navigation Satellite Systems (GNSS) receivers. A GNSS discriminator design method based on optimization technique is proposed in this paper to meet these requirements. Firstly, the discriminator structure based on a linear-combined code is given. Then the requirements of ideal discriminator function are converted into the mathematical constraints and the objective function to form a non-linear optimization problem. Finally, the problem is solved and the local code is generated according to the results. The theoretical analysis and simulation results indicate that the proposed method can completely remove the false lock points for BOC signals and provide superior multipath mitigation performance compared with traditional discriminator and high revolution correlator (HRC) technique. Moreover, the proposed discriminator is easy to implement for not increasing the number of correlators.
Mathematical Model of Non-Coherent-DLL Discriminator Output and Multipath Envelope Error for BOC (α, β) Modulated Signals  [PDF]
Khaled Rouabah, Chebir Saifeddine, Salim Atia, Mustapha Flissi, Djamel Chikouche
Positioning (POS) , 2013, DOI: 10.4236/pos.2013.41008

In this paper we propose the derivation of the expressions for the non-coherent Delay Locked Loop (DLL) Discriminator Curve (DC) in the absence and presence of Multipath (MP). Also derived, are the expressions of MP tracking errors in non-coherent configuration. The proposed models are valid for all Binary Offset Carrier (BOC) modulated signals in Global Navigation Satellite Systems (GNSS) such as Global Positioning System (GPS) and Future Galileo. The non-coherent configuration is used whenever the phase of the received signal cannot be estimated and thus cannot be demodulated. Therefore, the signal must be treated in a transposed band by the non-coherent DLL. The computer implementations show that the proposed models coincide with the numerical ones.

杨力 薄煜明 田明浩?
计算机科学 , 2008,
Abstract: boc调制技术在扩频通信中的应用已日趋广泛。为此,本文在对boc调制信号的功率谱和自相关特性进行深入研究,以及将其与bpsk调制相比存在的优势进行深入分析的基础上,以boc(10,5),bpsk(10.23)为例,进行了基于fft的同步捕获环路的设计与仿真,并重点就不同干信比条件下两者的捕获性能进行了分析。结果表明,在一定条件下boc调制信号具有更好的抗干扰能力,为进一步抗干扰技术的研究提供了理论基础。
Research of Anti-jamming Characteristic for BOC Signal

YANG Li,BO Yu-Ming,TIAN Ming-Hao,

计算机科学 , 2008,
Abstract: Binary-Offset-Carrier waveforms will be applied widely in the spreading communication, so based on the deeply research on power spectra and autocorrelation characteristic of BOC waveforms and the deeply analysis on the advantage compare to the BPSK waveforms, the FFT in-phase acquisition ring has been designed and simulated, besides, the acquisition ability of this two waveforms on the different J/S is analyzed. The result shows that the BOC waveforms have the better anti-jamming ability in the given condit...
Synthesis of the Key Precursor of Hirsutellide A
Yanjie Xu,Xuemin Duan,Meiling Li,Liqin Jiang,Guangle Zhao,Yi Meng,Ligong Chen
Molecules , 2005, DOI: 10.3390/10010259
Abstract: Hexadepsipeptide 2, the precursor of Hirsutellide A (1), was synthesized in an overall yield of 45% from N-Boc-Me-Gly via three coupling reactions using dicyclohexylcarbodiimide (DCC), O-(7-azabenzotriazol-1-yl)-N,N,N’,N’-tetramethyl- uronium hexafluorophosphate (HATU) and bis(2-oxo-3-oxazolidinyl)phosphinic chloride (BOP-Cl), respectively.
Ranging Property of the Dual-Band Band Limited Signal (DBBLS)
Advances in Electrical and Computer Engineering , 2012, DOI: 10.4316/aece.2012.03014
Abstract: The Dual-Band Band Limited Signal (DBBLS) is a signal with its power spectral density consisting of two separate lobes. Signals that can be considered as DBBLS are for example signals with BOC, AltBOC modulation, signals modulated on two close carriers and many other signals, which are used in modern satellite navigation systems. This signal advantage is its excellent ranging property. The parted power spectral density enables processing the DBBLS as a single wideband signal in single-channel receiver or as two narrow band signals in two-channel receiver. The signal processing of the ranging signals is based on the calculation of the cross-correlation function, which can be calculated from the signal measured by the two-channel receiver by the derived method more efficiently than from the whole signal. The two-channel processing has nearly optimal performance, but the hardware and computation complexity is much lower. The developed method can by applied, for instance, for the processing of the Galileo E5 signal or pair of the Compass L1 signals.
物理化学学报 , 2005,
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