Author
David Slepicka
Bio: David Slepicka is an academic researcher from Czech Technical University in Prague. The author has contributed to research in topics: Frequency domain & Sine wave. The author has an hindex of 7, co-authored 27 publications receiving 143 citations.
Papers
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TL;DR: The expression of the maximum of the interference error caused by the fundamental sine-wave component on the amplitude estimation of harmonic components of a harmonically distorted sine wave by the interpolated discrete Fourier transform method with maximum sidelobe decay windows is derived.
Abstract: This paper focuses on estimating the amplitude of harmonic components of a harmonically distorted sine wave by the interpolated discrete Fourier transform (IpDFT) method with maximum sidelobe decay windows. The expression of the maximum of the interference error caused by the fundamental sine-wave component on the amplitude estimation of harmonic components is derived. In addition, for a signal corrupted by stationary white noise, the statistical efficiency of the IpDFT method is investigated with respect to the single-tone unbiased Crame?r-Rao lower bound (CRLB). Based on the derived expressions, a constraint is derived ensuring that interference from the fundamental component could practically be neglected. Finally, the performance of the IpDFT method is compared with that of the energy-based method on the basis of theoretical, simulation, and experimental results and with that of a state-of-the-art method according to simulation and experimental results.
31 citations
01 Dec 2009
TL;DR: The application of inverse function, which is dependent on the possibility to derive the inverse function to the function approximating the INL(n) curve, is published in the paper.
Abstract: One of the most important parameter of ADC which negatively influence its quality is its nonlinearity. The correction of this imperfection can be accomplished in the output data but only if the nonlinearity is well characterized. Two methods — application of look-up table or an analytical inverse function of INL(n) curve — from other possibilities can be used for the ADC nonlinearity correction. The first results of correction using look-up table were published in [5]. The application of inverse function, which is dependent on the possibility to derive the inverse function to the function approximating the INL(n) curve, is published in the paper.
17 citations
03 May 2010
TL;DR: In this paper, the performance of several up-to-date nonparametric frequency estimators is compared with regard to the most common signal parameters, including bias, standard deviation and consumption time.
Abstract: This paper deals with the performance of several up-to-date nonparametric frequency estimators. The algorithms of frequency estimation are introduced and their bias, standard deviation and consumption time are compared with regard to the most common signal parameters.
13 citations
TL;DR: New propagation formulas for the uncertainty evaluation for the characterization of digitizing waveform recorders are proposed in this paper and have been validated on simulated and actual signals.
Abstract: New propagation formulas for the uncertainty evaluation for the characterization of digitizing waveform recorders are proposed in this paper. The frequency domain figures of merit, as defined in IEEE Std. 1057, have been considered to present useful addenda to the standard. The proposed formulas have been validated on simulated and actual signals.
11 citations
10 May 2011
TL;DR: In this article, the stability of the fundamental frequency of 16.7 Hz of European railway networks is observed and its influence on processing higher order harmonics is evaluated by means of amplitude frequency spectrum, short-time Fourier transform and residuals of sine-wave fitting.
Abstract: In this paper the stability of the fundamental frequency of 16.7 Hz of European railway networks is observed and its influence on processing higher order harmonics is evaluated. The stability is analyzed by means of amplitude frequency spectrum, short-time Fourier transform and residuals of sine-wave fitting.
10 citations
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TL;DR: In this article, several methods of power system harmonics estimation are critically reviewed and classified based on the type of analysis tool and applications and the key issues and challenges in harmonics estimations are highlighted.
185 citations
TL;DR: A comparison was made between the digital spectra obtained for several speech sounds and those obtained with 50‐cps constant‐bandwidth analog filters, and within expected limits, the agreement was good.
Abstract: Digital spectral analysis offers certain advantages over analog techniques: (1) the equivalent bandwidth of the analysis can be varied easily and (2) complicated calibration procedures are not required. A real‐time analog‐to‐digital magnetic‐tape recording system, designed as part of future instrumentation that will record digitized noise or speech signals and calculate their spectra with special purpose computer, records 31 250 digitized analog time samples per second in a 9‐bit code. Currently, an IBM‐7094 data‐processing system is programmed to perform trapezoidal integration of the Fourier integral to obtain the spectrum of the digital recordings. The Fourier transform of a 16‐msec square pulse differed from the calculated values by less than 4% of the actual amplitudes in the frequency range 0–5000 cps. A comparison was made between the digital spectra obtained for several speech sounds and those obtained with 50‐cps constant‐bandwidth analog filters. Within expected limits, the agreement was good. T...
89 citations
TL;DR: An approach for power system harmonic phasor analysis under asynchronous sampling is proposed, based on smoothing sampled data by windowing the signal with the four-term fifth derivative Nuttall (FFDN) window, and then calculating harmonicphasors in the frequency domain with an improved fast Fourier transform (IFFT) algorithm.
Abstract: An approach for power system harmonic phasor analysis under asynchronous sampling is proposed in this paper. It is based on smoothing sampled data by windowing the signal with the four-term fifth derivative Nuttall (FFDN) window, and then calculating harmonic phasors in the frequency domain with an improved fast Fourier transform (IFFT) algorithm. The applicable rectification formulas of the IFFT are obtained by using the polynomial curve fitting, dramatically reducing the computation load. The FFDN window can effectively inhibit the spectral leakage and the picket fence effect can be modified by the IFFT algorithm under asynchronous sampling, and the overall algorithm can easily be implemented in embedded systems. The effectiveness of the proposed method was analyzed by means of simulations and practical experiments for multifrequency signals with the fluctuation of the fundamental frequency and with the presence of white noise and interharmonics.
79 citations
TL;DR: This paper presents a fast and accurate approach for real-time estimation of moderate time-varying harmonics of voltage/current signals via rotational invariance technique (ESPRIT)-assisted adaptive wavelet neural network (AWNN).
Abstract: Field measurement of harmonic distortion is a fundamental requirement for monitoring, analysis, and/or control of power system harmonics. Fast and accurate estimation of time-varying harmonics is a key to realize many objectives of the smarter and cleaner grid such as harmonic source identification, improved active filter control for mitigation of harmonics, and smart meters for harmonic pollution metering. This paper presents a fast and accurate approach for real-time estimation of moderate time-varying harmonics of voltage/current signals. The proposed method is based on estimation of signal parameters via rotational invariance technique (ESPRIT)-assisted adaptive wavelet neural network (AWNN). The AWNN provides quick estimates (twice every fundamental cycle with only half-cycle data as input) of the dominant harmonics, whereas the ESPRIT complements it to handle time-varying signals with higher accuracy. The salient features of the proposed method are validated on the simulated and experimental signals of stationary and time-varying nature.
74 citations
TL;DR: The interpolated FFT algorithm based on the minimized sidelobe window is considered, and its calculate procedure and formulas are given, which is free of solving high-order equations, making the method a good choice for real-time applications.
Abstract: This paper focuses on the low-computation harmonic-analysis procedure with sufficient suppression of spectral leakage and picket-fence effect. The interpolated FFT algorithm based on the minimized sidelobe window is considered, and its calculate procedure and formulas are given, which is free of solving high-order equations. The implementation of the proposed algorithm in the digital-signal-processor (DSP) based three-phase harmonic ammeter is also introduced. The proposed algorithm has the major advantages that the calculate formulas for harmonic parameters can be easily implemented by hardware multipliers, making the method a good choice for real-time applications. The simulation and application results validate the accuracy and efficiency of the proposed algorithm.
62 citations