9762 papers found
The paper deals with mathematical fundamentals of the generalized nonsubtractive dithering method (which can be used in A/D converters and sampling systems with repetitive sampling). The new concept is based on inverting a "dithering characteristic" F defined in the paper for arbitrary (but fixed) quantization functions. Errors of the method are assessed and analyzed in detail.
Accumulated clock signal jitter is a significant source of errors in many measurement systems. In this paper a new method of estimation of clock signal jitter will be discussed. This method enables to calculate an accumulated jitter and time-interval error [TIE] as a function of the clock cycles. The time-interval measurement system [TIMS], accommodated for jitter measurements and their application for estimations of jitter parameters will be also presented and discussed.
This paper presents the concept of time-varying Butterworth filters with linear phase response. The compensation of the phase characteristics is carried out with the aid of the phase shifter system. The paper shows that it is possible to shorten the transient state in low-pass phasecompensated analog filters by varying in time selected parameters. This paper contains simulation results of the proposed filters and comparison with the classic circuits.
The optimal design of an adaptive wavelet filter based on lifting scheme by means of evolutionary cultural algorithms is proposed, with the aim of filtering data for dynamic corrosion monitoring. First, in corrosion rate measurement through electrochemical impedance spectroscopy, the problem of uncertainty due to noise arising from underground disturbances in buried structures is stated. Then, the proposed adaptive filtering procedure is illustrated. Finally, the results of the experimental validation on two different corrosion case studies are highlighted.
In this paper, a non-iterative algorithm for amplitude and phase difference estimation of two acquired sinewaves is presented and analyzed. The method is based on the least-squares fitting of ellipses where the common signal frequency is eliminated from the algorithm. requires the strict definition of the convergence criteria to stop the iterative method.
In order to identify if a subscriber loop is suitable for DSL service, the transfer function of the loop has to be estimated. Several measurement techniques exist, however Single Ended Line Testing is gaining much attention lately. This method allows only measuring at the central office side and yields a reflectogram. One of the critical issues in the estimation of the transfer function from this data is the correct extraction of the features of the reflectogram. This paper presents a new feature extraction algorithm for a previously reported transfer function estimator. It starts by...
In different industrial applications, such as injection molding and/or hot rolling, it is necessary to measure pressure in critical environmental conditions where the temperature can reach values in the range of 350-380°C. In these cases, a fluid with low thermal conductivity is now typically used in order to transfer the pressure to the sensitive element, while preserving it from overheats. A preferred solution would be that of obtaining new sensing elements with an intrinsic capability of operation over an extended temperature range. Silicon piezoresistors are unsuitable for use in...
Sun sensors are used to measure the orientation of the satellite in orbit using the sun as a reference. This paper includes the preliminary design of a sun sensor, the design and implementation of an automatic testing system and a preliminary characterization of the most important components.
In the paper, two approaches to measurements of circuit functions of analog parts of mixed-signal systems controlled by microcontrollers are presented. They base on the utilization of internal resources of the microcontrollers. The first approach uses an analog to digital converter (ADC), an analog comparator and a timer. The second one uses only the ADC and the timer. The measurement procedures are realized also by the microcontroller. As an example, the transfer voltage function of a circuit function was chosen.
In this paper it is shown that for the purpose of nonlinear power amplifier behavioural modelling, the sampling rate can be set to the Nyquist rate of the input signal, rather than to the Nyquist rate of the output signal by making use of Zhu’s generalized sampling theorem. This claim is supported by measurements on a basestation power amplifier. The findings are that the model error obtained when the output signal is sampled at the Nyquist rate of the input signal is approximately 1.5 dB higher than when the sampling rate is set to the Nyquist rate of the output signal. However, if a...