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Although the digital world gains in importance due to the decreasing feature size of the transistors, the analog building blocks remain indispensable. The design of the interface between the two worlds has to comply with the strict requirements of both sides. The presented research focusses on the design of current steering DI A converters in the modem telecommunication systems of tomorrow.An accurate description of both the static and the dynamic behaviour is of the utmost importance when designing a current steering D/A converter with a high performance. A new formula has been derived that accurately describes the INL-yield of a D/A converter as a function of the transistor mismatch behaviour in a given technology. The influence of systematic errors introduced by linear and quadratic gradients has to be minimised by the use of special switching schemes. Based on these elements, two 12 bit and one 14 bit current steering D/A converter have been implemented.Apart from the three well known factors influencing the dynamic behaviour of the DI A converter, a fourth element has been introduced. The frequency dependency of the output impedance has a negative effect on high resolution, high speed current steering DI A converters. Taking this new element into account during the design resulted in the realisation of a 10 bit D/A converter with a Nyquist performance in the entire frequency band for a clock frequency up to 1 GS/s.To determine the optimal segmentation level of a current steering DI A converter, a statistical analysis has been performed. It could be concluded that if the requirement dictated by the transistor mismatch of the unit current sources is fulfilled , both the INL and the DNL error are smaller than 112 LSB regardless of the number of bits implemented in a binary way. A low segmentation level implies a low decoder complexity and as such leads to a small power and area consumption. Based on these findings , a fully binary 10 bit D/A converter has been realised with a small power consumption and a good dynamic performance.The second part of this work is focussed on transistor mismatch. An overview is given of the most important mismatch models and on the influence of both the immediate surroundings and the used transistor topology. Also the link between the static performance of a current steering D/A converter and the extraction of the transistor vi mismatch parameters has been investigated. It is suggested that a current steering D/A converter could act as a test structure for matching characterisation.

This paper compares international and domestic inflation expectations and inflation credibility, and hypothesises about a possible link or disconnect between inflation expectations and inflation credibility among South Africans. No similar tests have previously been performed using South African data, and there is also a general lack of domestic and international literature on any such possible link or disconnect. While research shows that inflation expectations are taken into account by all countries targeting inflation, inflation credibility is very seldom considered. Although the hypothesis is confirmed in certain instances, it is refuted by a disconnect between the inflation expectations and inflation credibility of male and female respondents in South Africa, which cannot be explained by available data.

This paper examines the housing-output growth nexus in South Africa by accounting for the time variation in the causal link with a bootstrapped rolling Granger non-causality test. We use quarterly data on real gross domestic product, real house prices, real gross fixed capital formation and number of building plans passed. Our data span 1971Q2-2012Q2. Using full sample bootstrap Granger causality tests, we find a uni-directional causality from output to number of building plans passed; a uni-directional causality from real house price to output and a bi-directional causal link between residential investment and output. However, using parameter stability tests, we show that estimated VARs are unstable, thus full-sample Granger causality inference may be invalid. Hence, we use a bootstrap rolling window estimation to evaluate Granger causality between the housing variables and the growth rate.In general, we find that the causality from housing to output and, vice versa, differ across different sample periods due to structural changes. Specifically speaking, house price is found to have the strongest causal relationship with output compared to residential investment and number of building plans passed, with real house price showing predictive ability in all but one downward phase of the business cycle during this period.