The analysis of the distortion which results when frequency-modulated waves are passed through linear networks is investigated by the Fourier method and the Quasi-steady-state method. The major enphasis is placed on the Fourier method, and extensive digital computer programs are developed to allow this method to be implemented on the modern, high-speed digital computer. In the Fourier method, the frequency-modulated wave which is applied to the input of a linear network is broken up into its Fourier spectrum. Each of the resulting ‘'sideband'' frequencies is then passed through the network and is subjected to alterations in amplitude and phase. The output wave is then synthesized by taking the vector sum of the "weighted" sideband components. In contrast to the single pair of sideband frequencies generated by amplitude modulation, the spectrum of a frequency-modulated wave contains an infinite number of sideband components. Fortunately, only a relatively small number of these sidebands have significant influence on the total makeup of the waveform. The number of significant sidebands is proportional to the value of modulation index. When the modulation index is high, the number of significant sidebands is very large and the number of computations required by the Fourier method becomes enormous. Previously considered to be completely impractical, the Fourier method was usually abandoned in favor of the Quasi-steady-state approach. However, the digital computer techniques developed in the course of this investigation allow for a fast, economical, and convenient analysis based on the Fourier method even when the modulation index is relatively high. Analyses were performed for values of modulation index up to 45 and techniques are discussed for increasing this range. The Quasi-steady-state method is based on the assumption that the frequency of the input wave is changing slowly enough that the frequency of the output wave at any instant is equal to the "instantaneous fregquency' of the input wave. This method is inherently in error since it neglects the transient terms generated by the changing frequency. To compensate for this error, it is the general practice to incorporate correction terms, usually in the form of an infinite series. The Quasi-steady-state method is more effective at low modulating frequencies (high modulation index). While the analysis contained in this paper considers in detail only a first-order correction, the application of higher-order correction terms is discussed. The results obtained from applying both analyses to a complex, multi-section filter indicate that the computer solution of the Fourier method is preferable for intermediate values of modulation index. Experimental verification of the Fourier method is obtained by simulating the system on an analog computer. The advantages of this rather novel approach are discussed in some detail. The agreement between the results predicted by the digital computer and those obtained experimentally leaves no doubt to the validity and accuracy of the analysis. Digital computer programs for analyzing the distortion using each of the above methods are given. Subprograms are also included, some of which can be used independently. Among these are a program that computes Bessel functions of the first kind for positive and negative orders and a program that computes the minimum phase shift of a network from its atténuation. All programs are written in the FORTRAN IV computer language and were executed on the IBM 7040/1401 system. / Ph. D.

This work presents a study of the adaptive equalization techniques designed to improve the bit error rates of digital transmissions degraded by intersymbol interference in radio communication. This thesis considers the following structures: the linear transversal equalizer (LTE), the decision feedback equalizer (DFE), the lattice equalizer, and the maximum likelihood sequence estimation (MLSE) equalizer. Least mean square (LMS) and recursive least squares (RLS) algorithms are used as the adaptive algorithms for these equalizers. Lattice-DFE, DFE, and MLSE with an RLS algorithm are recommended to be implemented in mobile systems because of their better performances. A two-ray Rayleigh fading channel model is used to simulate the mobile channels. The results show that adaptive equalization can significantly improve the performance of mobile communications if the channel does not change too fast. The simulation shows that if the delay (T) of the second ray is too small, the adaptive equalization will degrade the BER performance, and the value of T at which the adaptive equalizer can improve the BER is determined by the speed of the mobile channel variation. Also, simulation results obtained by using SIRCIM, a real world indoor channel simulator, shows that adaptive equalization has good performance in slowly varying channels. An equalizer working in indoor high data rate systems has a BER less than 10-3 at 15 dB Eb/Noâ ¢ The SMRCIM urban channel model is also developed and implemented for equalization simulation. Finally, equalization structures for differential modulation techniques are proposed. / Master of Science

Two research projects are proposed that rely on Tools for open Reconfigurable Computing (TORC) and the openness of the Xilinx tool chain. The first project, the Embedded FPGA Transmitter, relies on the ability to add arbitrary routes to a physical FPGA which serve no obvious purpose. These routes can then mimic an antenna and transmit directly from the FPGA. This mechanism is not supported utilizing standard hardware description languages; however, the Embedded FPGA Transmitter requires measurements on a real FPGA to determine success. The second project is a back-end tools accelerator designed to reduce the compilation time for FPGA times. As the complexity of FPGAs have exceeded over a million logic cells, the compilation problem size has greatly expanded. The open-source project, TORC, provides an excellent framework for new FPGA research that provides physical, real-world results to ensure the applicability of the research. / Master of Science

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The U.S. Army’s Hardened Subminiature Telemetry and Sensor Systems (HSTSS) program has engaged the M/A-COM Corporation to work in the development of a highly accurate, crystal controlled telemetry transmitter chip set to be used in Army and other U.S. military munitions. A critical factor in this work is the operating environment of up to 100,000-g launch accelerations. To support the Army in this project, M/A-COM is developing integrated Voltage Controlled Oscillators (VCO) for L and S band, a silicon synthesizer/phase locked loop (PLL) IC, and a family of power amplifiers. Lastly, the transmitter module will be miniaturized and hardened using M/A-COM’s latest chip-onboard mixed technology manufacturing capabilities. This new chip set will provide the telemetry engineer with unprecedented design flexibility. This paper will review the overall transmitter system design and provide an overview for each functional integrated circuit.

Wireless devices have become an integral part of our everyday lives. Cell-phones, PDA's, Wi-Fi enabled laptops, smart homes and appliances, and automated highway systems are some of the examples of wireless devices and networks in common use. More and more applications and functionalities are constantly being added to these devices, and to support these new applications high data rate communication is required between the wireless devices. Achieving high data rates with wireless communication is impeded by severe fluctuations in the received signal strength (called fading) due to mobility, the exponential attenuation of signal power with distance (called path loss), and interference due to simultaneous transmissions by different users at the same time or over same frequency band. Two of the promising techniques to mitigate the effects of fading, path loss, and interference are: using multiple antennas at the transmitter and receiver, and employing extra nodes (called relays) in between the transmitter and its receiver to relay the transmitter's message to its receiver. This dissertation identifies the optimal transmit and receive strategy with multiple antennas that maximizes the transmission capacity of an ad-hoc wireless network. The transmission capacity is defined as the maximum number of transmitter-receiver pairs that can simultaneously communicate under a per transmission quality of service constraint. This dissertation also presents novel relay transmission strategies for multiple antenna equipped relay based communication that achieve near optimal performance, with Shannon capacity and diversity-multiplexing tradeoff (DMT) as the performance metrics. The Shannon capacity is defined as the maximum rate of reliable communication, while the DMT characterizes the maximum diversity gain for a given value of multiplexing gain in a multiple antenna system. DMT is used as the benchmark, since transmission strategies that meet the DMT are guaranteed to leverage both the advantages of multiple antenna systems. / text

by Kin Kwong Leung. / Thesis submitted in: November 1999. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 67-[70]). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Code Division Multiple Access (CDMA) --- p.1 / Chapter 1.1.1 --- The Cellular Concept --- p.2 / Chapter 1.2 --- Fading and Power Control --- p.3 / Chapter 1.2.1 --- Large Scale Fading --- p.3 / Chapter 1.2.2 --- Small Scale Fading --- p.4 / Chapter 1.2.3 --- Power Control --- p.5 / Chapter 1.2.4 --- Standard Interference Function --- p.5 / Chapter 1.3 --- Previous Work --- p.6 / Chapter 1.3.1 --- Power Control --- p.6 / Chapter 1.3.2 --- Convergence Analysis --- p.8 / Chapter 1.4 --- Scope of this Thesis --- p.8 / Chapter 1.5 --- Organization of the Thesis --- p.9 / Chapter 2 --- System Model --- p.10 / Chapter 2.1 --- System and Definitions --- p.10 / Chapter 2.2 --- Varying Link Gains Model --- p.11 / Chapter 2.3 --- SIR model in CDMA System --- p.13 / Chapter 2.4 --- Simulation Model --- p.14 / Chapter 3 --- Fade Margin --- p.17 / Chapter 3.1 --- Introduction --- p.17 / Chapter 3.2 --- Fixed-step Power Control Algorithm --- p.18 / Chapter 3.3 --- Definitions and Feasibility of SIR --- p.19 / Chapter 3.3.1 --- Definition --- p.19 / Chapter 3.3.2 --- Feasibility --- p.20 / Chapter 3.4 --- Performance Analysis on Fading Channel --- p.22 / Chapter 3.4.1 --- Single-User --- p.22 / Chapter 3.4.2 --- Multiple-User --- p.24 / Chapter 4 --- Generalized Step Power Control Algorithm --- p.28 / Chapter 4.1 --- Introduction --- p.28 / Chapter 4.2 --- Generalized Fixed Step Power Control Algorithm --- p.29 / Chapter 4.3 --- Existence of the Solution --- p.30 / Chapter 4.4 --- Parameter Optimization --- p.31 / Chapter 4.4.1 --- Single-User --- p.34 / Chapter 4.4.2 --- Multiple-User --- p.37 / Chapter 4.5 --- Performance Analysis --- p.41 / Chapter 4.5.1 --- Single-User --- p.41 / Chapter 4.5.2 --- Multiple-User --- p.42 / Chapter 4.6 --- Hybrid Scheme --- p.47 / Chapter 5 --- Convergence Analysis --- p.49 / Chapter 5.1 --- Introduction --- p.49 / Chapter 5.2 --- Totally Asynchronous Models --- p.50 / Chapter 5.3 --- Normalized Interference Function --- p.52 / Chapter 5.4 --- Existence of Quantized Solution --- p.53 / Chapter 5.5 --- Convergence Theorem --- p.55 / Chapter 6 --- Conclusion and Future Work --- p.64 / Chapter 6.1 --- Conclusion --- p.64 / Chapter 6.2 --- Future Works --- p.65 / Bibliography --- p.67

Digital transmitters offer several advantages over conventional analog transmitters such as reconfigurability, elimination of scaling-unfriendly, power hungry and bulky analog blocks and portability across technology. The rapid advancement of technology in CMOS processes also enables integration of complex digital signal processing circuitry on the same die as the digital transmitter to compensate for their non-idealities. The use of this digital assistance can, for instance, enable the use of highly efficient but nonlinear switching-class power amplifiers by compensating for their severe nonlinearity through digital predistortion. While this shift to digitally intensive transmitter architectures is propelled by the benefits stated above, several pressing challenges arise that vary in their nature depending on the frequency of operation - from RF to mmWave. Millimeter wave CMOS power amplifiers have traditionally been limited in output power due to the low breakdown voltage of scaled CMOS technologies and poor quality of on-chip passives. Moreover, high data-rates and efficient spectrum utilization demand highly linear power amplifiers with high efficiency under back-off. However, linearity and high efficiency are traditionally at odds with each other in conventional power amplifier design. In this dissertation, digital assistance is used to relax this trade-off and enable the use of state-of-the-art switching class power amplifiers. A novel digital transmitter architecture which simultaneously employs aggressive device-stacking and large-scale power combining for watt-class output power, dynamic load modulation for linearization, and improved efficiency under back-off by supply-switching and load modulation is presented. At RF frequencies, while the problem of watt-class power amplification has been long solved, more pressing challenges arise from the crowded spectrum in this regime. A major drawback of digital transmitters is the absence of a reconstruction filter after digital-to-analog conversion which causes the baseband quantization noise to get upconverted to RF and amplified at the output of the transmitter. In high power transmitters, this upconverted noise can be so strong as to prevent their use in FDD systems due to receiver desensitization or impose stringent coexistence challenges. In this dissertation, new quantization noise suppression techniques are presented which, for the first time, contribute toward making watt-class fully-integrated digital RF transmitters a viable alternative for FDD and coexistence scenarios. Specifically, the techniques involve embedding a mixed-domain multi-tap FIR filter within highly-efficient watt-class switching power amplifiers to suppress quantization noise, enhancing the bandwidth of noise suppression, enabling tunable location of suppression and overcoming the limitations of purely digital-domain filtering techniques for quantization noise.

However, the proposed receiver and channel selection scheme still suffer from the mismatches picked up during RF-to-IF conversion. Therefore, a system called phase and amplitude mismatch cancellers is adopted to deal with the problem. Existing implementations neglected several critical behaviors of the cancellers, and provide image rejection ratios (IRR) ranging from 50dB to 65dB only. These behaviors include (i) arithmetic underflow, (ii) angular obscurity and (iii) spurious intermodulation products (IMD) produced by cancellers. We analyzed them and established several design rules, by which a far better IRR of at least 82.5dB was achieved. The system makes the proposed receiver and channel selection method feasible. / In traditional receivers involving intermediate frequency (IF), two different RF channels, Signal and Image, are converted to the same IF and overlap with each other. The Signal is always wanted with the Image eliminated, so each RF LO frequency can only select one RF channel. By digital low-IF, the IF-to-baseband conversion can be configured so that either channel can be selected, then each RF LO frequency can select two RF channels. This enhanced channel selection scheme can effectively reduce the number of LO frequency locations by half as well as the requirements of RF PLL frequency synthesizer. An existing approach makes use of configurable sampling scheme to achieve the same aim, but its use of analog sampling circuits results in phase and amplitude mismatches, from which the performance of image rejection suffers. Digital low-IF does not have this problem, since no mismatches are introduced to the signals after digitization. / The proposed digital low-IF Weaver receiver, together with the enhanced channel selection scheme and the phase and amplitude mismatch cancellers, are demonstrated to be feasible by a multi-band multi-mode receiver prototype supporting GSM900 and WCDMA. / The receiver architecture proposed in this thesis makes use of Weaver architecture with digital low-IF. Its flexibility allows for any operations to be performed on the digitized signals, as well as the enhanced channel selection scheme proposed in this thesis. / Chan Pak Kee. / "September 2007." / Adviser: Chiu Sing Choy. / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4924. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 152-162). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Kin Kwong Leung. / "August 15, 2003." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (p. 77-[82]). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Yau Chin Hang Herman. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 90-92). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- To A Localization --- p.10 / Chapter 2.1 --- Linear Estimator --- p.13 / Chapter 2.2 --- The Approximate Maximum Likelihood (AML) estimator --- p.14 / Chapter 2.3 --- Estimator for Linear BS --- p.18 / Chapter 3 --- TDoA Localization --- p.22 / Chapter 3.1 --- AML in TDoA localization --- p.27 / Chapter 4 --- Discussions of Application Considerations --- p.32 / Chapter 4.1 --- The Non-Line-of-Sight Problem --- p.33 / Chapter 4.2 --- Multipath Propagation --- p.34 / Chapter 4.3 --- Optimum placement of 4 sensors --- p.35 / Chapter 5 --- Simulation Studies --- p.44 / Chapter 5.1 --- Measures of Accuracy --- p.45 / Chapter 5.2 --- Simulations for non-linear array BSs --- p.47 / Chapter 5.2.1 --- Simulation 1: MS locating inside the enclosed area formed by 3BSs --- p.48 / Chapter 5.2.2 --- Simulation 2: The MS is outside the enclosed area formed by 3 BSs --- p.52 / Chapter 5.2.3 --- Simulation 3: The MS is inside the enclosed area formed by 6 BSs --- p.55 / Chapter 5.2.4 --- Simulation 4: The MS locates outside the enclosed area formed by 6 BSs --- p.58 / Chapter 5.3 --- ML estimator for linear array --- p.62 / Chapter 5.3.1 --- Simulation 5: Three BSs with equal spacing --- p.62 / Chapter 5.3.2 --- Simulation 6: Three BSs with non-equal spacing --- p.64 / Chapter 5.4 --- TDOA localization simulations --- p.66 / Chapter 5.4.1 --- Simulation 7: TDOA localization with 4 equal spacing microphones and the speaker is inside the enclosed area --- p.66 / Chapter 5.5 --- To see the performance of optimum placement --- p.69 / Chapter 5.5.1 --- Simulation 8: Optimum placement of the 4th microphone if the other three are fixed --- p.70 / Chapter 5.5.2 --- Simulation 9: Fixing 2 microphone and find the optimum placement of the other two microphones --- p.74 / Chapter 5.5.3 --- Simulation 10: The optimum placement of microphones without constraint --- p.78 / Chapter 6 --- Conclusions and Suggestions for future work --- p.81 / Chapter 6.1 --- Conclusions --- p.81 / Chapter 6.2 --- Suggestion for future work --- p.83 / Appendices --- p.85 / Chapter A --- The relationship between range variance and range difference variance --- p.85 / Chapter B --- The Cramer-Rao Lower Bound (CRLB) for TDoA and ToA cases --- p.87