Principles of complex software and hardware design of the sub-optimal low-energy cyclic ADC (CADC) are presented. The extended conversion algorithm for estimates computing is discussed. Upper boundaries of CADC resolution, rate of conversion and the ways they can be achieved are analyzed. Properties and general advantage of sub-optimal CADC are discussed and investigated in simulation experiments.

The progress in the technology of the analogue to digital converters (ADCs) suppresses the error effects linked with its inherent architecture. Multiperiodicity of differential nonlinearity and the impact of analog components at the ADC input on the integral nonlinearity prefers unified behavioural error model expressed as one dimensional image in the code k domain. The paper presents two new methods for low code frequency testing. The first one is based on synchronous detection of higher harmonics in ADC output record. Second apply repetitive best fitting method to estimate the harmonics. detection by multiplone utilise combination of the fast. testing methods, which allow to identify the model parameters. The high code frequency model component could be determined by fast histogram method using reduced FS triangular voltage.

In this paper we present a new sensor able to detect absolute and incremental angular position, having a simple construction. The sensing technique is based on the magnetostrictive delay line principle. The dependence of the sensor on the sensing core rotation was measured and filtered. Thus, a sinusoidal response with an uncertainty of 0.05% was realised. We also demonstrate the ability of this principle idea to be used as a dynamic displacement sensor in the range of 15 mm.

The main purpose of this paper is to present some metrological aspects of identification and grouping of harmonics and interharmonics and calculation of total harmonic. The Virtual Instrument for identification of distorted signal spectrum is described and the demonstration may take place at the presentation of the paper at the oral or poster session. We define the total harmonic and interharmonic distortion coefficient and analyse its sensitivity to variation in fundamental and interharmonic frequency and sensitivity to incompleteness of samples for five different cases: rectangular window, triangular, Hanning, Hamming and Blackman windows. The virtual test signal was selected arbitrarily. This signal was processed first by the virtual harmonic analyser, in such a way that all components were identified without any errors, and then the signal was analysed according to the requirements specified in IEC 61000-30-4 draft standard, in which also Harmonic Groups (HG) and Interharmonic Groups ( IHG) are defined.

Only complete expression of measurement result (measurement uncertainty included) makes possible correct interpretation of measurement results and reliable decision-making. Estimation of measurement uncertainty is complex and time consuming for some stand-alone digital instruments, and especially for indirect measurements results. It is possible to integrate calculation of measurement uncertainty into digital instrument containing processor. For direct and indirect measurements it is advantageous to develop appropriate software application for integration of digital instrument(s) and personal computer into an automated measuring system with the capability to display complete measurement result. The idea is illustrated on measurement of load-losses of power transformers using power analyzer. Software application for instrument transformers errors correction and reduction of measurement uncertainty is also briefly described.