International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / In 1992, international space agencies became concerned that increasing frequency band congestion, together with attempts by the mobile telephone industry to obtain additional bandwidth, would result in substantially more interference incidents. The CCSDS undertook a technical study to identify and recommend more bandwidth efficient modulation schemes, which would permit more users to co-exist in a frequency band while reducing interference incidents. This paper describes the contribution of the Jet Propulsion Laboratory (JPL) to that effort.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Commercial FQPSK-B receivers traditionally use symbol-by-symbol detection and have a 2 dB Eb=No loss relative to ideal QPSK at a bit error rate (BER) of 10^(-5). An enhanced FQPSK-B receiver using a Viterbi algorithm (VA) to perform trellis decoding is simulated and shown to have a 1.2 dB Eb=No improvement over symbol-by-symbol detection for 10^(-5)5 BER at the cost of increased complexity. A simplified Viterbi receiver with a reduced trellis and significantly less complexity is introduced with only a slight BER degradation compared to the full Viterbi receiver. In addition, a theoretical bit error probability expression for the symbol-by-symbol FQPSK-B receiver is derived and compared with simulation results.

<p>Sigma-delta modulators (SDM) have come up as an attractive candidatefor analog-to-digital conversion in single chip front ends thanks to the continuousimproving performance. The major disadvantage is the limited bandwidthdue to the need of oversampling. Therefore, extending these convertersto broadband applications requires lowering the oversampling ratio (OSR) inorder. The aim of this thesis is the investigation on the topology and structureof sigma-delta modulators suitable for wideband applications, e.g. wireline orwireless communication system applications having a digital baseband aboutone to ten MHz.It has recently become very popular to feedforward the input signal inwideband sigma-delta modulators, so that the integrators only process quantizationerrors. The advantage being that the actual signal is not distorted byopamp and integrator nonlinearities. An improved feedforward 2-2 cascadedstructure is presented based on unity-gain signal transfer function (STF). Theimproved signal-to-noise-ratio (SNR) is obtained by optimizing zero placementof the noise transfer function (NTF) and adopting multi-bit quantizer.The proposed structure has low distortion across the entire input range.In high order single loop continuous-time (CT) sigma-delta modulator, excessloop delay may cause instability. Previous techniques in compensation ofinternal quantizer and feedback DAC delay are studied especially for the feedforwardstructure. Two alternative low power feedforward continuous-timesigma-delta modulators with excess loop delay compensation are proposed.Simulation based CT modulator synthesis from discrete time topologies isadopted to obtain the loop filter coefficients. Design examples are given toillustrate the proposed structure and synthesis methodology.Continuous time quadrature bandpass sigma-delta modulators (QBSDM)efficiently realize asymmetric noise-shaping due to its complex filtering embeddedin the loops. The effect of different feedback waveforms inside themodulator on the NTF of quadrature sigma-delta modulators is presented.An observation is made that a complex NTF can be realized by implementingthe loop as a cascade of complex integrators with a SCR feedback digital-toanalogconverter (DAC), which is desirable for its lower sensitivity to loopmismatch. The QBSDM design for different bandpass center frequencies relativeto the sampling frequency is illustrated.The last part of the thesis is devoted to the design of a wideband reconfigurablesigma-delta pipelined modulator, which consists of a 2-1-1 cascadedmodulator and a pipelined analog-to-digital convertor (ADC) as a multi-bitquantizer in the last stage. It is scalable for different bandwidth/resolutionapplication. The detail design is presented from system to circuit level. Theprototype chip is fabricated in TSMC 0.25um process and measured on thetest bench. The measurement results show that a SNR over 60dB is obtainedwith a sampling frequency of 70 MHz and an OSR of ten.</p>

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

by Sze Tsz-leung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 91). / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Basic concepts of Monte Carlo integration --- p.1 / Chapter 1.1.1 --- Importance sampling --- p.4 / Chapter 1.1.2 --- Control variate --- p.5 / Chapter 1.1.3 --- Antithetic variate --- p.6 / Chapter 1.1.4 --- Stratified sampling --- p.7 / Chapter 1.1.5 --- Biased Estimator --- p.10 / Chapter 1.2 --- Some special methods in Monte Carlo integration --- p.11 / Chapter 1.2.1 --- Haber´ةs modified Monte Carlo quadrature I --- p.11 / Chapter 1.2.2 --- Haber's modified Monte Carlo quadrature II --- p.11 / Chapter 1.2.3 --- Weighted Monte Carlo integration --- p.12 / Chapter 1.2.4 --- Adaptive importance sampling --- p.13 / Chapter Chapter 2 --- New methods / Chapter 2.1 --- The use of Newton Cotes quadrature formulae in stage one --- p.17 / Chapter 2.1.1 --- Using one-dimensional trapezoidal rule --- p.17 / Chapter 2.1.2 --- Using two-dimensional or higher dimensional product trapezoidal rule --- p.21 / Chapter 2.1.3 --- Extension to higher order one-dimensional Newton Cotes formulae --- p.32 / Chapter 2.2 --- The use of Guass quadrature rule in stage one --- p.45 / Chapter 2.3 --- Some variations of the new methods --- p.56 / Chapter 2.3.1 --- Using probability points in both stages --- p.56 / Chapter 2.3.2 --- Importance sampling --- p.59 / Chapter 2.3.2.1 --- Triangular distribution --- p.60 / Chapter 2.3.2.2 --- Beta distribution --- p.64 / Chapter Chapter 3 --- Examples / Chapter 3.1 --- Example one: using trapezoidal rule as basic rule --- p.73 / Chapter 3.1.1 --- One-dimensional case --- p.73 / Chapter 3.1.2 --- Two-dimensional case --- p.80 / Chapter 3.2 --- Example two: Using Simpson's 3/8 rule as basic rule --- p.85 / Chapter 3.3 --- Example three： Using Guass rule as basic rule --- p.86 / Chapter Chapter 4 --- Conclusion and discussions --- p.88 / Reference --- p.91

This thesis reports original work on digital compensation for frequency dependent transfer characteristics and errors in digital PAM/CPFSK (Pulse Amplitude Modulation/Continuous Phase Frequency Shift Keying) quadrature modulators.A particularly flexible and cost effective approach to the implementation of the base-band section of a radio transmitter is to synthesise base-band signals digitally using a DSP (Digital Signal Processor). This approach is limited, however, by the transfer characteristics and errors in the implementation of practical analogue sub-systems. These practical limitations result in undesirable in-band frequency-dependent shaping of the transmitted signals. In the case of FM (Frequency Modulation) signals, this leads to the generation of unwanted side-lobes in the transmitted RF signal spectrum that interfere with signals in adjacent frequency channels. This results in the transmitted signal failing to meet transmission standards requirements.The digital compensation techniques developed and presented in this thesis allow the reduction of undesirable in-band frequency-dependent signal shaping. It is shown that this enables strict requirements on the spectral emissions from the FM transmitter to be met using a flexible and cost effective DSP based modulator system.The contributions of the thesis are in three primary areas:(i) The development of a structure for frequency dependent digital compensation.(ii) The formulation and solution of an optimisation problem that allows the free parameters within the structure to be determined such that effective reduction of unwanted in-band frequency-dependent signal shaping is achieved.(iii) The development of techniques that allow the digital compensation procedure to be successfully implemented on a practical DSP platform.The new digital compensation structure that is proposed uses two digital FIR (Finite ++ / Impulse Response) filters in the digital base-band section of the quadrature modulator: one in the in-phase (I) channel and one in the quadrature (Q) channel. The tap-weights of the FIR filters are determined by solving two optimisation problems: one for each channel. The optimisation problems are formulated using a new approach that ensures that the degrees of freedom in the optimisation i.e., the FIR filter tap-weights, are used effectively to meet the objective of reducing in-band frequency-dependent signal shaping in analogue sub-systems further down the transmission path.A characterisation of the solutions to the optimisation problems enables the identification of techniques that need to be adopted to successfully implement the proposed digital compensation on a practical DSP-based system.The digital compensation technique is demonstrated by implementing and testing the technique on a DSP platform. The results of experimental studies are presented which clearly demonstrate that the digital compensation technique leads to substantial reductions in adjacent channel interference.

This thesis considers likelihood inferences for generalized linear models with additional random effects. The likelihood function involved ordinarily cannot be evaluated in closed form and numerical integration is needed. The theme of the thesis is a closed-form approximation based on Laplace's method. We first consider a special yet important case of the above general setting -- the Mantel-Haenszel-type model with overdispersion. It is seen that the Laplace approximation is very accurate for likelihood inferences in that setting. The approach and results on accuracy apply directly to the more general setting involving multiple parameters and covariates. Attention is then given to how to maximize out nuisance parameters to obtain the profile likelihood function for parameters of interest. In evaluating the accuracy of the Laplace approximation, we utilized Gauss-Hermite quadrature. Although this is commonly used, it was found that in practice inadequate thought has been given to the implementation. A systematic method is proposed for transforming the variable of integration to ensure that the Gauss-Hermite quadrature is effective. We found that under this approach the Laplace approximation is a special case of the Gauss-Hermite quadrature. / Graduation date: 1994

The rapid growth of the market for short-range wireless devices, with standards such as Bluetooth and Wireless LAN (IEEE 802.11) being the most important, has created a need for highly integrated transceivers that target drastic power and area reduction while providing a high level of integration. The radio section of the devices designed to establish communications using these standards is the limiting factor for the power reduction efforts. A key building block in a transceiver is the frequency synthesizer, since it operates at the highest frequency of the system and consumes a very large portion of the total power in the radio. This dissertation presents the basic theory and a design methodology of frequency synthesizers targeted for short-range wireless applications. Three different examples of synthesizers are presented. First a frequency synthesizer integrated in a Bluetooth receiver fabricated in 0.35μm CMOS technology. The receiver uses a low-IF architecture to downconvert the incoming Bluetooth signal to 2MHz. The second synthesizer is integrated within a dual-mode receiver capable of processing signals of the Bluetooth and Wireless LAN (IEEE 802.11b) standards. It is implemented in BiCMOS technology and operates the voltage controlled oscillator at twice the required frequency to generate quadrature signals through a divide-by-two circuit. A phase switching prescaler is featured in the synthesizer. A large capacitance is integrated on-chip using a capacitance multiplier circuit that provides a drastic area reduction while adding a negligible phase noise contribution. The third synthesizer is an extension of the second example. The operation range of the VCO is extended to cover a frequency band from 4.8GHz to 5.85GHz. By doing this, the synthesizer is capable of generating LO signals for Bluetooth and IEEE 802.11a, b and g standards. The quadrature output of the 5 - 6 GHz signal is generated through a first order RC - CR network with an automatic calibration loop. The loop uses a high frequency phase detector to measure the deviation from the 90° separation between the I and Q branches and implements an algorithm to minimize the phase errors between the I and Q branches and their differential counterparts.

Cette thèse est construite autour de l'approximation et la représentation des fonctions sur la sphère avec des applications pour des problèmes inverses issues de la géodésie et de l'imagerie médicale. Le plan de la thèse est structuré de la façon suivante. Dans le premier chapitre, on donne le cadre général d'un problème inverse ainsi que la description du problème de la géophysique et de la M/EEG. L'idée d'un problème inverse est de retrouver une densité à l'intérieur d'un domaine (la boule unité modélisant la terre ou le cerveau humain), à partir des données des mesures d'un certain potentiel à la surface du domaine. On continue par donner les principales définitions et théorèmes qu'on utilisera tout au long de la thèse. De plus, la résolution du problème inverse consiste dans la résolution de deux problèmes : transmission de données et localisation de sources à l'intérieur de la boule. En pratique, les données mesurées sont disponibles que sur des parties de la sphère : calottes sphériques, hémisphère nord de la tête (M/EEG), continents (géodésie). Pour représenter ce type de données, on construit la base de Slepian qui a des bonnes propriétés sur les régions étudiées. Dans le Chapitre 4 on s'intéresse au problème d'estimation de données sur la sphère entière (leur développement sous la base des harmoniques sphériques) à partir des mesures partielles bruitées. Une fois qu'on connait ce développement, on applique la méthode du meilleur approximant rationnel sur des sections planes de la sphère (Chapitre 5). Ce chapitre traite trois types de densité : monopolaire, dipolaire et inclusions pour la modélisation des problèmes, ainsi que des propriétés de la densité et du potentiel associé, quantités mises en relation par un certain opérateur. Dans le Chapitre 6 on regarde les Chapitres 3, 4 et 5 du point de vue numérique. On présente des tests numériques pour la localisation de sources dans la géodésie et la M/EEG lorsqu'on dispose des données partielles sur la sphère.

This thesis aims to use a hybrid quadrature polar modulator (HQPM) for enhancing average efficiency of 3G mobile transmitter with power control. The HQPM consists of a quadrature modulator instead of a phase modulator in the polar modulator for processing the RF modulated carrier and a Class-S modulator for processing the envelope signal. In addition, the instantaneous magnitude of the quadrature modulated signal is propotional to the instantaneous envelope magnitude. As a result, the output feed-through and gain-compression phenomenon in the polar modulator can be improved. The digital baseband processor realized by FPGA can generate CDMA2000 1x baseband signal with excellent modulation accuracy. For enhancing the average transmit efficiency, the output PA is realized as Class-E design. But the Vdd/AM and Vdd/PM nonlinear effects of the Class-E PA distort the output signal. To solve this problem, a digital predistorter is presented to compensate the nonlinear distortions. The proposed HQPM-based transmitter can simultaneously achieve high efficiency and high linearity over a wide modulated output power range.