The primary aim of the thesis is to determine the spectrum efficiency and power penalty of multi-level Subcarrier Multiplexing (SCM) transmission. To perform quantitative analysis, this thesis first develops a fiber transmission model. When there is one SCM transmission channel, it is found that the power penalty due to multi-level is 5 dB per bit at the same bit error rate (BER). For multiple channel SCM transmission, to reduce adjacent channel interference (ACI), it is found that binary transmission has the best spectrum efficiency for Non-Return-to-Zero (NRZ) pulses at the same BER. However, if raised-cosine pulses are used, 32-ary transmission is found to be the most efficient in spectrum use because of the smaller ACI.

This thesis presents a discrete time implementation and analysis of the generalized impulse response model proposed by Altes. This model is a generalization of the weighted sum of time delayed delta functions typically used to describe the impulse response of scattering targets. The target chosen for the analysis is the rigid acoustic sphere. The coefficients of the generalized model are used to calculate estimates of the radius of the sphere, which is known in advance for testing purposes. The accuracy of the radius estimates indicates the accuracy of the model coefficients. The generalized model is shown to be superior from the standpoint of radius estimation. An estimator for the time of arrival of a signal of unknown but deterministic form is derived. It is based upon a generalized likelihood ratio test whose structure accommodates the generalized model. This estimator performs well in high levels of noise.

The minority carrier generation lifetime is a parameter of central importance in the characterization, design, and operation of solid state devices. Various methods have been described for measuring the lifetime using an MOS capacitor (MOS-C). They can be classified according to the kind of voltage applied, the quantities measured, and the required elaboration of experimental results. This thesis discusses two groups of methods for determining the lifetime using an MOS-C: pulsed voltage methods and voltage sweep methods. The objective of this thesis is to give a comprehensive review and comparison of various methods for determination of minority carrier lifetime using an MOS-C. To accomplish this objective, the theory is presented as it exists in each respective reference, and the experiment is conducted based on the theory. Sometimes the theory is modified to include effects not considered in the original reference.

The electrical properties (resistance, capacitance, and inductance) of spherical solder bumps are computed. The solder bump is modeled using a finite, lossless transmission line model. The resistive, capacitive, and inductive effects are calculated separately then combined using superposition. The transmission line impedance for a 300 μm solder bump is calculated and the effect on a 100 nsec rise time signal is computed. Several methods to calculate fatigue lifetime are examined then related to reliability and design parameters. Methods to improve reliability are examined and their impact on electrical performance discussed.

Numerical modeling of the beams generated from an ultra-wide bandwidth pulse-driven dipole array is considered. Several multi-derivative systems are simulated with these numerical results. The analytic performance bounds on energy, intensity, and beam width of the pulsed beams generated by the pulse driven array are derived. Numerical comparisons are made between the pulsed beams generated by driving the dipole array with monochromatic continuous waves with two distinctive amplitude tapers, Gaussian pulses with two distinctive amplitude tapers, and three types of localized waves. The specific localized waves used include the modified power spectrum pulse and the 1/2 and 3/2 superluminal pulses. The energy pattern of the pulse-driven dipole array is studied for each of these cases. The effect of element density on these energy patterns is also examined. The results obtained show that the modified power spectrum pulse truly outperforms the monochromatic continuous wave by a wide margin for multi-derivative systems.

A method to predict appropriate dielectric constants and thicknesses for double dielectric substrate microstrip structures to minimize forward crosstalk is presented. Ratios of the elements in the capacitance matrix are compared to those in the inductance matrix to determine if forward crosstalk will be minimized. Curves showing C(rat) where C(rat) is the ratio of the C₁₁ element to the C₁₂ element, as a function of the relative permitivity, εᵣ and SPICE simulations are presented for particular geometries. The method accurately predicts combinations of dielectrics that will produce a structure exhibiting greatly reduced crosstalk.

Asymptotic expressions are obtained for the electric field due to a current propagating on a horizontal semi-infinite wire above the earth. First, exact integral representations are derived for the electric field due to a current on a semi-infinite wire in a general multi-layered medium. The resulting integral expressions are then specialized for the problem of a semi-infinite wire above the earth. The resulting expressions involve a semi-infinite integration over an integrand containing the incomplete Lipschitz-Hankel integrals. The steepest descent technique is applied to the direct and reflected terms separately, thereby providing a far-zone approximation for the field (E α r⁻¹). A recurrence relationship is then developed which allows the r⁻² term in the asymptotic expansion to be computed from the previously computed r⁻¹ term. A numerical comparison between the following three methods is carried out: numerical integration, one-term (1/r) approximation, and two-term (1/r²) approximation. It is shown that two-term solution yields more accurate results than that of the one-term solution, especially when the problem of a finite length wire above the earth is considered. The two-term expansion provides accurate results for the fields when 0.1 λ < r < ∞ and it consumes much less computation time than the numerical integration solution.

The effect of neutron irradiation on power metal-oxide-semiconductor field effect transistors (power MOSFETs) breakdown voltage has been investigated. Power MOSFETs of both n- and p-channel with manufacturer's rated breakdown voltage between 100 to 500V were radiated up to accumulated neutron fluence of 5x10¹⁴ neutron/cm² Considerable increase in the breakdown voltages were observed in n-type MOSFETs after 10¹³ neutron/cm² and to p-type MOSFETs after 10¹² neutron/cm² The increase in breakdown voltages is due to the decrease in the mean free path caused by the neutron-irradiation-induced defects. The effect of positive trapped charge oxide and the termination structure to the breakdown voltage were considered. S-PISCES 2B device simulation was used to investigate the change in the b coefficient of Chynoweth's law that relates to the mean free path. Two empirical models are presented: one predicts the power MOSFET breakdown voltage after a certain amount of neutron fluence and the other considers the change in the b coefficient after some amount of neutron radiation to predict the change of breakdown voltage in a device simulation.

A method to reduce Electromagnetic Interference (EMI) of multiple switching waveforms by harmonic cancellation is presented. The waveforms considered are input currents generated by 'n' Discontinuous Mode (DCM) Flyback Switched Mode Power Supplies (SMPS) that share a common source. The waveforms are modeled as ideal triangular waveforms and a Fourier analysis is performed to determine the phase relationship, θ, that minimizes the EMI. The combined EMI is minimum when θ=360°/n and maximum when θ=0°. A system of two DCM Flyback SMPS is designed in such a way that both 0° and 180° phase shifts between input current waveforms are possible. In both cases EMI filters are designed to meet EMI standard MIL-STD-461. The system is simulated and constructed and the experimental results are presented. These results demonstrate the accuracy of the modeled waveform and the reduction of conducted EMI when optimal phasing is achieved.

The design of a digital focus servo control system for an optical disk tester is presented. A total focus misregistration budget is established for three primary disturbances: disk runout, shock, and system noise. The design of an analog servo system is established first to determine the required bandwidth. The analog design is transformed into a digital representation using pole/zero mapping techniques. The transformation to the digital domain includes the effects of the control law computation time, the D/A sample and hold, and the anti-aliasing filter. Modeling and simulation of the digital system in the frequency and time domain are used to obtain the phase margin and the transient response. The transient response overshoot is larger than that obtained from a second order model. The larger overshoot is a result of the additional phase delay produced in the digital system that reduces the gain margin drastically compared to the analog case.