Thesis (Masters Diploma (Electrical Engineering)) -- Cape Technikon, Cape Town, 1991 / This thesis describes the design, development and implementation of a monitoring and data logging system for a multi-line telephone console as required by the Account Enquiry section of the Department of Posts and Telecommunications.

Thesis (Masters Diploma(Technology) -- Cape Technikon, Cape Town, 1991 / The call for the system design in this book came from a field that grew to be a part of millions of lives in this country. It is a sport which has developed to have a major infrastructure, with large sums of money involved. In fact, the money involved has made it one of the largest tax earners country wide. Due to its high development, competition has become furious and breeders will do their utmost to produce a competitor which would have the slightest edge on the next one. As most people would know by now, the discussion is about the Horse Racing Industry. During the years, owners have relied on various exercising programs and breeding of proven winners to produce new ones. To give the animal the necessary training and simply run it on experience is no longer sufficient. A more scientific approach has become necessary. There exists a need for a system whereby one could monitor certain physiological aspects of the animal. This would not only allow the physical condition of each horse to be monitored, but also allow a more effective and specialized exercise program for each individual animal to be developed, thereby not only improving its ability, but saving on time as well. Tests that were considered included ECG, temperature, and speed measurements. Existing equipment performing the first two tests require the animal to be stationary. This defeats the object of the exercise, as information should be relevant to the animal when under strain. During test periods, the ideal situation would be to allow the horse to perform its exercise routine around the track without any interference. This could best be done by monitoring all the.necessary data via a radio link and having most of the analyzing apparatus in a small and light as possible package on the animal itself.

Thesis (Masters Diploma(Electrical Engineering)) -- Cape Technikon, Cape Town,1989 / various types of electronic card test equipment are freely available today for different types of electronic printed circuit boards. A company certainly wants to pick the most suitable tester to suit their needs, and more importantly a tester that will fit into their bUdget. Today a company can easily import in-circuit testers that will cost well in the reglon of six figures. The cheaper the equipment go, the less features one can expect from the equipment. Like all other big decisions in life, this might also be a tough one for a company. Part one of this thesis will consider most of these questions, and will also give more insight on what type of specifications to look for. This section will also explain the different types of faults that occur, the repair costs involved, different types of card testers available and some of their features. Advanced in-circuit testing techniques will also be explained. Part two of this thesis describes the design and development of the Identif ier Card Tester. The" Program Control and Impulse Sender Card", (referred to as "Identifier Card") is one of the cards used in a system called "Electronic Identifier". The electronic identifier was developed to enable a subscriber directory number, a line or equipment numbers, or in general, the origin of information and classes-of-service to be determined by way of an existing connection within a telephone exchange. The system was designed for the purpose of incorporating it into the existing public exchanges where no identifier wires are available. It operates on the principle of a switching circuit (line) tester. The identification pulses are evaluated with the aid of 6 mm bistable magnetic ring cores according to the current steering principle. The program control and the output circuit uses a transistor, a magnetic core/transistor or a magnetic core/thyristor circuit. The electronic identifier is mostly used with "Routiners" in Electra-mechanical exchanges. The biggest percentage of failures on these systems are caused by the Identifier Card and hence the request for the development of a "Identifier Card Tester".

Thesis (Masters Diploma (Electricity Engineering) -- Cape Technikon, Cape Town,1991 / At the time of the design the maximum allowable operating frequency for an output power of between 200 and 250 watts was 100 kHz. Although a 600 kHz operating frequency could have been achieved, it would only be at a very low output power level. To maximise the current components available, a 210 watt 100 kHz direct-off-line switched-mode power supply was developed. The design presented can be used to power any compatible IBM XT/AT personal computer. The prototype was tested. An overall efficiency of 61% was achieved. The final prototype required 1 521 cm3 and weighed approximately 980 g, representing a power to volume ratio of 0.14 W/cm3 (2.26 W/inch3). Detailed procedures are also presented to help with the design and selection of the reactive components. Special design features include the half-bridge push-pull topology, MOSFETS as power switches, digital current limiting, primary power limiting, multiple outputs and fault counting to name but a few.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. / The open-ended coaxial probe is revisited as a broadband measurement system for general high frequency permittivity measurements. Three coaxial probes were developed that are suited for the measurement of both liquids and solids. The components of a permittivity measurement system were investigated and improvements were made to the coaxial probe where needed. This includes the development of a full wave code with great calculation time improvements without sacrificing accuracy. This code allows measurements to be performed in a high frequency laboratory and the permittivity extracted without any mentionable delay. A capacitance model that better describes the impedance of an open-ended coaxial line is also suggested that can be used for real-time permittivity extraction over a limited frequency range. Calibration formed a vital part of the project and great time was spent developing a TRL and a SOLT calibration set for the coaxial probe geometry. The combination of the TRL and SOLT standards also allows measurement of the residual errors after calibration and is used in an uncertainty analysis of the extracted permittivity. Well known materials such as PTFE, PVC, methanol and water were measured to test the probes. The measured dielectric constants are all within 3% of values quoted in literature. The loss term of the samples are also in good agreement with the expected values.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. / Integrated circuits are expensive to manufacture and it is important to verify the correct operation of a circuit before fabrication. Efficient, though accurate, parameter extraction of post-layout designs are required for estimation of circuit success rates. This thesis discusses electrical netlist and fast parameter extraction techniques suited for both intraand inter-gate connections. This includes the use of extraction windows and look-up tables (LUTs) for accurate inductance and capacitance estimation. These techniques can readily be implemented in automated layout software where fast parameter extraction is required for timing analysis and gate placement.

The determination of an individual's right to privacy is mainly a nontechnical matter, but the pragmatics of providing it is the central concern of the cryptographer. This thesis has sought answers to some of the outstanding issues in cryptography. In particular, some of the theoretical, application and implementation problems associated with a Public Key Cryptosystem (PKC). The Trapdoor Knapsack (TK) PKC is capable of fast throughput, but suffers from serious disadvantages. In chapter two a more general approach to the TK-PKC is described, showing how the public key size can be significantly reduced. To overcome the security limitations a new trapdoor was described in chapter three. It is based on transformations between the radix and residue number systems. Chapter four considers how cryptography can best be applied to multi-addressed packets of information. We show how security or communication network structure can be used to advantage, then proposing a new broadcast cryptosystem, which is more generally applicable. Copyright is traditionally used to protect the publisher from the pirate. Chapter five shows how to protect information when in easily copyable digital format. Chapter six describes the potential and pitfalls of VLSI, followed in chapter seven by a model for comparing the cost and performance of VLSI architectures. Chapter eight deals with novel architectures for all the basic arithmetic operations. These architectures provide a basic vocabulary of low complexity VLSI arithmetic structures for a wide range of applications. The design of a VLSI device, the Advanced Cipher Processor (ACP), to implement the RSA algorithm is described in chapter nine. It's heart is the modular exponential unit, which is a synthesis of the architectures in chapter eight. The ACP is capable of a throughput of 50 000 bits per second.

The analysis of digital active networks is developed in this thesis, starting from the definitions of digital amplifiers and digital amplifier arrays and concluding with the presentation of general analysis techniques for N-port digital active networks. The analysis techniques are then tested by comparing the results of practical experiments with numerical evaluations of the derived transfer functions using a computer. The basic techniques necessary for the synthesis of digital active networks are described with an example, and the thesis is concluded with a discussion of the advantages of digital active networks over their analogue equivalents.

The precise control of a robot manipulator travelling at high speed constitutes a major research challenge. This is due to the nonlinear nature of the dynamics of the arm which make many traditional, linear control methodologies inappropriate. An alternative approach is to adopt controllers which are themselves nonlinear. Variable structure control systems provide the possibility of imposing dynamic characteristics upon a poorly modelled and time varying system by means of a discontinuous control signal. The basic algorithm overcomes some nonlinear effects but is sensitive to Coulomb friction andactuator saturation. By augmenting this controller with compensation terms, these effects may largely be eliminated. In order to investigate these ideas, a number of variable structure control systems ~re applied to a low cost industrial robot having a highly nonlinear and flexible drive system. By a combination of hardware enhancements and control system developments, an improvement in speed by a factor of approximately three was achieved while the trajectory tracking accuracy was improved by a factor of ten, compared with the manufacturer's control system. In order to achieve these improvements, it was necessary to develop a dynamic model of the arm including the effects of drive system flexibility and nonlinearities. The development of this model is reported in this thesis, as is work carried out on a comparison of numerical algorithms for the solution of differential equations with discontinuous right hand sides, required in the computer aided design of variable structure control systems.

For many years robots have been programmed at manipulator or joint level without any real thought to the implementation of sensing until errors occur during program execution. For the control of complex, or multiple robot workcells, programming must be carried out at a higher level, taking into account the possibility of error occurrence. This requires the integration of decision information based on sensory data. Aspects of robotic workcell control are explored during this work with the object of integrating the results of sensor outputs to facilitate error recovery for the purposes of achieving completely autonomous operation. Network theory is used for the development of analysis techniques based on stochastic data. Object level programming is implemented using Markov chain theory to provide fully sensor integrated robot workcell control.