Comprehensive Behavioral Modeling of Conventional and Dual-Tuning PLLs

This paper presents a modular and comprehensive nonlinear time-domain behavioral model for phase-locked loops (PLLs) that are suitable for analyzing the impact on the output signal of the noise contribution and nonidealities of the constituent building blocks. The model building blocks are described by Simulink submodels and can be configured to implement different PLL topologies. Postprocessing of the PLL output provides the PLL phase noise and spur-to-carrier-ratio performances. The calculated phase-noise spectra are compared with those obtained with the well-known linear model and with measurements. To show the flexibility of this approach, many case studies are reported; among them, the analysis of the spurs due to charge pump mismatch and the transient phase noise, and spurs performances of a PLL featuring a dual control of the voltage-controlled oscillator.      

Internal oxidation of Ag–VC composites

The internal oxidation (IO) of Ag–VC composites containing 5 vol.% of carbide was examined at three oxidation temperatures (350, 400, 600 °C). Two mechanisms were observed due to the formation of double oxides with relatively low-melting points. At temperatures below the lowest eutectic point in situ, or diffusion less IO, was observed with the formation and growth of oxide layers surrounding the initial carbide. At temperatures above the eutectic point IO resulted in the formation of liquid oxide pools, which grew in size and developed into a network of oxides within the metal matrix. The kinetics confirmed the presence of two distinct mechanisms.     

Development of a substitutive light source for indoor daylight calculations

The central focus of the paper is to present the results of the last 2 years of the research work on development of a substitutive light source for daylight calculation of the illuminance indoors. In the paper, calculation of spatial distribution of daylight according to the new CIE standard is discussed. Another focal topic is the calculation of photometric data of a light source which substitutes vertical window or vertical window opening in computer calculations. Through the development of photometric data for a light source, so that it can be imported into calculation software, this software becomes more powerful and useful.     

Investitionsbewertung in Krisensituationen

Critical economic conditions, which also applies to the wood processing industry, as a rule accelerate the process of innovations and rationalizations. Investments in innovation and rationalization can be assessed only in specific time periods. Consequently, the effects of investments can be evaluated only with a limited level of dependability. The risk factor is therefore very much present in these types of investments, but this can be minimized by using suitable, and more objective methods. These methods are discussed in this paper.     

Ökonomische Bewertung und Auswahl von Fertigungssystemen in der Holzindustrie

The estimation of investment projects of various manufacturing methods for the same production have, above all, to be based on the economies guaranteed by the particular method in the course of its life-span. In regard to a life-span of several years, dynamic estimation methods have to be employed allowing a detached evaluation of the investestment projects. In this article the “internal economies interest rate method” was discussed by means of a practical example on behalf of German Republican conditions and flexible production methods enabling a dynamic estimation of the economies between both production methods.     

Life expectancy prediction and application properties of novel polyurethane based thickness sensitive and thickness insensitive spectrally selective paint coatings for solar absorbers

A novel Thickness Sensitive Spectrally Selective (TSSS PU B: a_s=0.90, e_T=0.20) paint coating on aluminium substrate was prepared from commercially available polyurethane binder (Binder B) (HELIOS TBLUS, SI) and black pigment (spinel (Mn–Fe)), in combination with trisilanol polyhedral oligomeric silsesquioxane (POSS), which served as pigment dispersant. Polyurethane resin binder B was selected because of its higher thermal stability (determined from thermogravimetric measurements (TG)) than polyurethane resin binder A, which has previously been used for making Thickness Insensitive Spectrally Selective (TISS PU A) coatings (a_s=0.90, e_T=0.38) deposited on copper absorbers (Kuni?, 2009 [36]).Thermal degradation of the TSSS PU B and TISS PU A coatings, both deposited on aluminium substrates, was studied by following, as close as possible, the methodology worked out within TASK 10 of the IEA's Solar and Heating Programme. Thermal load tests were performed in the temperature range from 170 to 200 °C at various time intervals (1, 6, 10, 15, 21 days). Degradation of the coatings was assessed using a variety of degradation indicators: changes of solar absorptance and thermal emittance determined from the hemispherical IR and VIS/NIR spectra, intensity changes of selected vibrational modes attributed to the polymeric backbone and ester and urethane linkages and combined with peel-off tests used as adhesion and cohesion indicators. The results revealed that degradation of the polyurethane resin binder was attributable to the breaking of the urethane linkages, also shown from the AFM and XPS spectra measurements. For the TISS PU A coating, the life expectancy was estimated to be 22.77 years (activation energy (E_a)=163.2 kJ/mol, T_eff=113.4 °C) while for the TSSS PU B coatings, it was at least 25.96 years (activation energy (E_a)=96 kJ/mol, T_eff=102 °C).     

Novel engineering approach to optimization of thermal comfort properties of hemp containing textiles

The aim of this research was to investigate the possibilities of producing comfort hemp containing textile fabrics by assembling a pure hemp yarn with other-fibre containing yarn. The plain knitted fabrics were produced from two-assembled hemp and three variants of cotton yarns which differed in twist level, all having the same linear density. The transport properties (air permeability, water vapour permeability and thermal resistance) of the hemp-based knitted fabrics were quantitatively analysed. The results obtained demonstrated that the introduction of cotton into hemp-based textiles reduces air and water vapour permeability with the downward trend in thermal resistance. The extent to which the transport properties varied among the hemp/cotton knitted fabrics was dependent on the twist intensity of the cotton yarns. Therefore, the yarn assembling technique is an effective way not only to combine different fibre properties but to take advantage of intrinsic properties of component yarns.     

IEC class 0.5 electronic watt–hour meter implemented with first-order sigma–delta converters

This paper presents a design of a precise electronic watt–hour meter implemented with first-order sigma–delta analog-to-digital converters. An efficient digital signal-processing circuit is introduced into the design where the whole signal processing is performed directly on an oversampled signal, eliminating the necessity for a decimation filter. It is shown that Gaussian noise, added to the input signal of sigma–delta modulators, decorrelates quantization error of first-order sigma–delta modulators and thus substantially reduces measurement error at low-signal amplitudes. The effect of added noise is analyzed by extensive behavioral simulations for various input signal amplitudes and for various input noise levels. The results show that IEC accuracy class 0.5 can be achieved with first-order sigma–delta converters and digital signal processing in the sigma–delta domain.     

Determination of stray light at the PTB goniophotometer facility

For improved luminous flux measurements, the Physikalisch-Technische Bundesanstalt (PTB) was equipped with a new robotic goniophotometer. In order to characterize this instrument, to reduce the combined measurement uncertainty, and to determine the respective uncertainty components, the influence of stray light on the measurement results was investigated. Considering the specific structure of the robotic goniophotometer, stray light was measured on-line by means of a purpose-built “back-looking” photometer. By this means, the influence of the luminous intensity distribution of each individual light source with regard to its stray light could be considered. Before the first experimental application, the invented procedure was tested by means of calculations using mathematical models. In this paper, the mathematical model for the calculation of stray light in the goniophotometer room is presented together with the calculation results and the results of the first measurements. The achieved results indicate that the recommended stray light measurements can decrease the total relative standard measurement uncertainty of luminous flux measurements down to 2 × 10⁻³.