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In this paper, the analysis of noise and sensitivity for different BP filter designs is observed. Calculation of the voltage noise spectral density, root mean square (RMS) value of the noise voltage, Schoeffler sensitivity and the multi-parameter sensitivity is done for the simply designed (SD) active RC, noise and sensitivity optimized (NO and SO) active RC, operational transconductance amplifiers (OTA-C) and switched capacitor (SC) filter designs. This is observed for the fourth-order Chebyshev band-pass filter, with central frequency fc = 4 kHz, bandwidth 1 kHz and pass-band ripple αmax = −0.1 dB. Cascade of two second-order sections is used for fulfilment realization of all four observing designs. Programming tools, such as MATLAB and SPICE (LTspice), are also used for the analyses. Highlights • We used three different designs and optimization (noise and sensitivity) procedure for design and optimize the fourth-order Chebyshev band-pass filter • Our results suggest which design is best to use for improving noise and sensitivity of this filter • MATLAB and SPICE software were used for calculations and simulations of different band-pass filter designs and analysis of noise and sensitivity

Transmission line parameters vary with environmental and operating conditions, thus introducing uncertainties in power flow studies and protection zone settings of relay protection equipment. Variations in line parameters are fundamental for the determination of static and dynamic line power ratings. Usually, nominal values are given without an associated confidence interval, and therefore an important piece of information is missing. With the proliferation of phasor measurement units (PMUs) that allows for synchronized measurements at different geographical positions arouse the possibility for simple and efficient measurements of line parameters. This article analyzes uncertainties associated with the estimation of line parameters, based on the equivalent $\pi $ model, valid for short-and medium-length transmission lines. This problem has been addressed in literature, but only from a theoretical perspective and the obtained results were verified with simulations only. Here, measurements conducted on two 220-kV transmission lines are analyzed. It was found that the correlation between voltage and current measurements must be taken into consideration when analyzing uncertainty propagation law. Only then statistical analysis of estimations matches the predictions obtained by applying the theoretical model. Accuracy limits were analyzed as well, but in this case some results were within the calculated limits, while others did not follow predictions. Improvements in accuracy limits’ determination require the separation of environmental and operating condition variations from deviations due to measurement equipment, thus requiring additional information.

In this paper an analysis of noise through four different approaches to filter design is performed. The voltage noise spectral density and root mean square (RMS) value of noise voltage for the simply designed (SD) active RC, noise optimized (NO) active RC, operational transconductance amplifiers (OTA-C) and switched capacitor (SC) filter design are calculated for fourth-order Chebyshev band-pass filter, with central frequency f c =4kHz, bandwidth 1kHz and pass band ripple $\alpha_{max}$=-0.1dB. For the achievement realization of all four designs a cascade of two second order sections are used. The analyses is performed using Matlab and SPICE (LTspice) programming tools.

In this paper, noise propagation through a two-stage nonlinear algorithm for measurement of harmonic distortion in power systems according to IEC 61000-4-7 is analyzed. Noise generated in the instrument’s input circuitry is considered as an aggregated noise source without detailed characterization of its origin. The first stage of the measurement algorithm is the discrete Fourier transform (DFT) of the input signal. Noise propagation through the DFT is analyzed by means of probability theory. The result of this analysis, the probability density function (pdf) of the DFT spectrum amplitudes, is used for characterization of the second stage of the measurement algorithm – the root-sum-square grouping of several spectrum components into a single harmonic distortion index. In this way, pdfs of the most common harmonic indices are derived and analyzed. The study presented reveals that noise generated in the input stage produces, besides the already known variance of the results, an offset in the harmonic distortion indices. Analysis of the resulting pdfs implies that an increase in the number of components in the grouping procedure increases the offset error, whereas the standard deviations are essentially independent of the number of components included in the group. The validity of the model derived has been tested with a prototype of a low-cost portable instrument for three-phase power quality measurements.

In this paper noise analysis of three different filter designs is performed. Voltage noise spectral density and RMS noise voltage in simply designed active RC, noise optimized active RC and switched capacitor (SC) filter design are calculated for fifth order Chebyshev low pass filter, with a cut-off frequency f c =3.4kHz, and pass-band ripple α max =−0.5dB. All three designs are realized as a cascade of two second order sections and one first order section. All filter analysis has been performed using MATLAB and SPICE program tools. Through the analysis it is shown that SC based filter has significantly lower noise when compared with active RC based filter.

The discrete time switched capacitor (SC) based filters have number of advantages over the classical continuous time active RC based filters, the one most important being reduced circuit silicon area, allowing SC filters to be integrated to a single monolithic integrated circuit (IC). In this paper we have designed fifth order Chebyshev low pass SC filter, with a cut-off frequency f_x=3.4 kHz, and pass-band ripple a_ma x =-0.5 dB, and we have compared its time and frequency performance with a performance of the active RC based filter. The both SC and active RC filters are realized as a cascade of two second order sections and one first order section. All filter analysis has been performed using MATLAB and SPICE program packages where SC based filter has shown significant noise and sensitivity improvement, when compared with active RC based filter., Vremensko diskretni filtri s preklapanim kapacitetima imaju niz prednosti nad klasičnim vremensko kontinuiranim aktivnim RC filtrima. Jedna od važnijih prednosti jest smanjena površina silicija, omogućavajući integraciju filtra u integriranoj thenologiji (IC). U ovom radu dizajniran je Chebyshev nisko propusni filtar s preklapanim kapacitetima s graničnom frekvencijom f_c = 3.4 kHz i valovitosti alpha_max = -0.5 dB, te su mu vremenska i frekvencijska svojstva uspoređena sa svojstvima aktivnog RC filtra. Oba filtra realizirana su kao kaskada dviju sekcija drugog reda te jedne sekcije prvog reda. Analiza oba filtra izvršena je u MATLAB i SPICE programskim paketima, te je kod SC filtra pokazano znatno smanjenje šuma i osjetljivosti u usporedbi s aktivnim RC filtrom.

In this paper general second-order low-pass and band-pass filter sections are presented. The voltage noise spectral density and Schoeffler sensitivity are calculated for the simple design procedure and for three different types of optimization. The optimization procedure is also done for the forth-order low-pass and band-pass filter. The resulting low noise and sensitivity is investigated using the RMS noise voltage and multi-parameter sensitivity measure. The optimization gives lower noise and lower sensitivity filters. All analyzes are performed using Matlab and Spice programming tools., U radu su prikazane opće filtarske sekcije drugog i četvrtog reda. Izračunati su spektralna gustoća napona šuma i Schoefflerova osjetljivost i to za jednostavan proračun te za tri različita tipa optimizacije. Optimizacija je takođ er provedena za nisko propusni i pojasno propusni filtar četvrtog reda. Dobiveni niski šum kao i osjetljivost ispitani su računanjem efektivne vrijednosti napona šuma i više-parametarske mjere osjetljivosti. Rezultati optimizacije daju filtre koji imaju manji šum k ao i osjetljivost. Svi su proračuni izvedeni korištenjem programskih alata Matlab i Spice.

The influence of noise on the measurement uncertainty of different harmonic indices calculated according to IEC grouping algorithms is analyzed in this paper. The results of a previously published paper are extended to cases where the input noise is superimposed on to the harmonic signal. Probability density functions (pdf) of the harmonic indices are obtained by means of numerical integration and are used for assessment of the statistical properties of the output noise. The values of the offset errors and standard deviations are compared to uncertainties obtained by applying the uncertainty propagation law, as indicated by The Guide to the Expression of Uncertainty in Measurement (GUM).

U radu je opisan prijedlog programa diplomskog sveučilišnog studija računarstva s opisom modula i kompetencija.

The realization possibilities of the third-order high-pass transfer functions with the real zeroes are discussed. The filter structure consists the CR ladder network with only one operational amplifier (OA), what will give the low sensitivity circuit with the low power consumption. In this paper, the OA provides the signal feedforward and in that case, the transfer function contains real zeroes, both in and out of the origin of complex plane. The frequency responses and the time responses are presented as well as the sensitivity and the noise analysis. The obtained results are confirmed with the SPICE.

Inclusion of the latest research work to a real life applications and achieving adaptive video signal postprocessing is a complex and timely task. The proposed framework breaks the filtering process into several distinct phases and enables a researcher to move at a faster pace by narrowing the scope of the research and enabling seamless integration of this work into inherently adaptive filtering process. Some of the benefits of this modular and adaptive framework have been presented on the example of the MPEG-4 postprocessing improvements., Uključivanje najnovijih istraživačkih dostignuća u svakodnevne primjene i postizanje adaptivnog postprocesiranja videosignala zahtjevan je zadatak za koji je potrebno mnogo vremena. Predloženi sustav dijeli postupak filtriranja u nekoliko jasno odvojenih faza te na taj način sužava opseg svakog pojedinog istraživanja. Time je omogućena jednostavna integracija novih dostignuća u inherentno adaptivan proces filtriranja, što omogućava osjetno brži napredak u istraživanju. Neke prednosti ovog modularnog i adaptivnog sustava prikazane su na primjeru poboljšanja procesa postprocesiranja videosignala kodiranog prema MPEG-4 normi.

Snimljeni audio signal pored željenog signala često sadrži i neželjeni signal koji mu je pridodan. U ovom je radu prikazan postupak projektiranja digitalnih filtara s konačnim impulsnih odzivom čija je svrha potiskivanje neželjenog signala., Very often, a recorded audio signal contains an added obstructive signal. This paper presents a method for designing digital filters of finite impulse response which are used in order to suppress an obstructive signal.

In this paper the Asymmetric Digital Subscriber Line (ADSL) analog front end (AFE) designs are described and compared. AFE is the part of ADSL modems most responsible for quality signal transmission over phone wires. It can be divided into the transmitting path (TX) circuitry, the receiving path (RX) circuitry and the hybrid network and transformer. The operations and realizations of each functional block are presented. There are the D/A converter, the filter and the line driver in the TX path and the voltage gain amplifier, the filter and the A/D converter in the RX path. The hybrid network and transformer process signals in both directions. Different fabrication technologies are used for the practical realizations of the AFE chip. The directions of the further developing are notified., U radu su opisane i uspoređene izvedbe ADSL analognog sučelja. Analogno sučelje kao dio ADSL modema najodgovornije je za kvalitetan prijenos signala preko telefonskih žica. Može se podijeliti u sklopove predajnog puta, prijamnog puta i hibridnu mrežu s transformatorom. Prikazan je rad i izvedbe svakog funkcijskog bloka. To su D/A pretvornik, filtar i izlazno pojačalo u predajnom putu te ulazno pojačalo, filtar i A/D pretvornik u prijamnom putu. Hibridna mreža i transformator prosljeđuju signale u oba smjera. Za praktičnu izvedbu AFE čipa koriste se razne tehnologije. Naznačene su smjernice daljnjeg razvoja.

U članku su predstavljene sljedeće metode nelinearnog upravljanja: neizrazito upravljanje i različite varijante upravljanja s promjenjivom strukturom i kliznim režimom. Ti su postupci upravljanja korišteni u simulacijama za poboljšanje slijeđenja trajektorije troosne planarne rotacijske robotske ruke. Kvaliteta slijeđenja trajektorije robota provjeravana je u simulacijama s promjenom parametara robota, složenim vanjskim smetnjama i šumom mjerenja. Rezultati simulacija dokazali su robusnost svih predstavljenih nelinearnih metoda upravljanja robotima., This paper presents the following nonlinear control methods: fuzzy control and different variations on variable-structure control with a sliding mode. These control methods are used in simulations for improvement of trajectory tracking for the three-axis planar articulated robot arm. The quality of robot trajectory tracking is tested in simulations with robot parameter change, complex external disturbances and measurement noise. The simulation results proved robustness of all presented nonlinear methods for robot control.

In this paper, different the third order filters designs with different transfer function approximations are discussed. The filters should fulfill the specifications for the VDSL signal processing. The standard transfer function approximations are chosen: the Butterworth, the Chebyshev, the Symmetric impulse response and the Elliptic. The filters are designed using the fully differential sections with the small number of elements to obtain the low noise and the high dynamic range, and the low sensitivity. The transfer functions and the filter elements are given and the sensitivity and the noise for each design are calculated. The best results are obtained for the third order filter where the second order block follow the first order block.

In this paper, an influence of real parameters of operational amplifier to the impedance tapered filter transfer function is analyzed. As an example, a second-order-low-pass (LP) and high-pass (HP) Sallen and Key filters with Butterworth and Chebyshev transfer function approximations are considered. Design tables with normalized element values for both cases are given. The filter elements were calculated using three different design criteria: equal resistors, capacitors and impedance tapered elements. Filter transfer functions are obtained using ideal and real operational amplifier. Real model of common operational amplifier is presented. Active sensitivities for all presented filters are shown. The results obtained by the analysis show significant influence of real amplifier in the frequency ranges higher than 100 kHz. Reduction of active sensitivities is obtained using impedance tapering, which fortunately, reduces the passive sensitivities as well.

Realization possibilities of the all-pole third-order transfer functions are discussed. For this purpose, the ladder network with a controlled voltage source in any shunt branch is used. The voltage source is controlled by the shunt branch voltage. The transfer functions are expressed with cumulants. Because of the high degree of symmetry, there are the rules for cumulant development. In this paper, the controlled voltage source with the controlling voltage placed in the shunt branch behind the source is considered. In this case, the transfer function contains only poles. The realization of the all-pole third-order transfer function is given in an example. The transfer function stability is analyzed using the Routh-Hurwitz criterion for the third degree polynomials.

Requirements for effective way of storing multimedia content are continuously increasing. Many compression techniques have been developed, but harsh compromise between coding efficiency and decompressed content quality still has to be made. Although that compromise is inevitable, techniques are being developed that can help lower the bit rate while still retaining the decompressed content quality. This paper discusses implementation and analysis of one such method - dynamic resolution conversion, that was introduced in version 2 of MPEG-4 standard.

Third order low-pass filters are analyzed. Two different configuration of General Impedance Converter (GIC) based filters are compared to two Sallen and Key (SAK) based structures. For GIC based third-order filters realization procedures are given. The transfer functions and the component values for the third-order filters with Butterworth response are presented. The sensitivity analysis is done, and the results of Monte Carlo runs, as well as Schoeffler sensitivities are shown. The best results are obtained with the GIC based filter, which use four capacitances for the realization.

Revolution speed measurement methods are analyzed. Three different measurement methods are presented and appropriate resolutions and relative errors are calculated The method which measures the time between two pulses gives the best results for slow rotation speeds. The method which counts the number of pulses in a fixed time window gives better results for high rotation speeds. Measurement optimization is done by measuring in two modes corresponding to the previous methods and the relative error is significantly decreased. A revolution counter is realized for measuring rotation speeds in the range 10-9999 r.p.m. with a sensor which gives one pulse per revolution. In the entire range the resolution of 1 r.p.m. is displayed. A microcontroller is used for switching between the measurement modes as well as for the rotation speed calculation and displaying.