Estimating the carrier frequency from a modulated waveform is one of the most important functions of a coherent signal receiver. Good performance and low bit error rates are obtained by coherent demodulation. Therefore, exact knowledge of the received signal carrier frequency is critical for communication systems. Also due to the spectral crowding, a high probability of channel interference can be observed. Under moderate carrier frequency offsets, data-aided estimators have been developed which have a high accuracy of estimation. However, for high frequency offsets the frequency estimator does not have the information of data or timing. In this thesis we propose a parametric based carrier frequency estimation of GMSK, which has improved performance over ad-hoc methods (delay and multiply) and has high resolution capability. In this thesis three methods are implemented over GMSK data to improve the performance and their results compared with the standard delay and multiply method. Two of these methods are parametric based estimators and one is a fast frequency estimator. Parametric based estimators were chosen partly due to their high resolution capabilities and mainly for their proven performance. Parametric based estimators were seen to have high computational load, and hence an alternate fast frequency estimator was implemented. The tradeoffs involved with respect to computational load and performance were shown. The contributions of this thesis include the verification of the validity of applying a parametric based approach on GMSK data, and compare the performances of parametric methods and fast frequency estimator. It is showii that such an approach has a better performance compared to non-data aided ad-hoc delay. and multiply methods. A closed loop configuration of the open loop parametric methods is suggested in the end. / Graduation date: 2004 / Best scan available. Figures are light on the original.

Thesis (MCIS - Computer and Information Sciences) -- AUT University, 2008. / Includes bibliographical references. Also held in print ( xi, 105 leaves : ill. ; 30 cm.) in the Archive at the City Campus (T 621.382 LOL)

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 203-208).

Thesis (M.S. in Civil Engineering)--Vanderbilt University, 2004. / Title from PDF title screen. Includes bibliographical references.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 83-90).

Diss.--Universität Graz, 2008. / Includes bibliographical references.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 139-144). Also available in electronic version. Access restricted to campus users.

Mobile device antenna design and isolation technologies are thoroughly investigated in this thesis. The antenna design parameters for mobile devices are quantified using practical restraints by analyzing almost 60 mobile handsets and the effect of materials, human tissue, manufacturing, and antenna type/placement on antenna design and then mapped into Wheeler-space that correlates the spherical wave modes with the antenna performance. The isolation technologies with mutual coupling anti-resonances are unified by a single performance parameter to distinguish them from the more traditional isolation technologies. This unifying performance parameter is the group delay between two antennas where high group delay indicates the presence of a bandstop filter in the form of either a PCB or an antenna modification. This thesis analyzes both PCB and antenna modifications with high group-delay and demonstrates these types of antennas can be placed in close proximity without affecting other performance parameters. It is also shown that both the PCB and antenna modifications contain two isolation methods where each isolation method is a mirror complement of the other method. Some antenna geometries can also increase the mutual coupling in order to improve the antenna performance using a phenomena called over-coupling. These over-coupled antenna systems can result in lower SAR for the cellular antennas and decreased array sizes for NFC/RFID/wireless-power antennas, resulting in better performance of antennas inside mobile devices. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / toc / Electrical and Electronic Engineering / Master / Master of Philosophy

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