Analysis of noise-reduction filter design by computer modelling

2021 ◽  
Author(s):  
V.E. Drach ◽  
P.V. Kondrashov ◽  
M.A. Savvin
Keyword(s):  
Noise Reduction ◽  
Noise Suppression ◽  
Filter Design ◽  
Computer Modelling ◽  
Short Circuit ◽  
Frequency Region ◽  
Structural Elements ◽  
Frequency Range ◽  
Family Of Curves ◽  
Parasitic Parameters

The article describes the principles of evaluating the design disadvantages of a noise-reduction filter. The characteristics of the developed equipment are influenced by many parameters, such as the inhomogeneity of the components used, the parasitic interference introduced by them, and noise induced from structural elements and external sources. At the same time, the search for and elimination of the reasons for the discrepancy between the parameters of the designed products requires more and more expenses during the development stages. That is why the problem of modeling equipment with parameters close to real ones and under conditions different from laboratory ones is urgent. To assess the influence of the above factors in the Qucs 0.0.19 program, a noise suppression filter was simulated, the introduced attenuation of which did not meet the requirements of the design documentation (this problem was identified due to the use of modern measuring equipment at the stage of serial production). A family of curves is constructed that describe the behavior of the circuit for various values of the parameters of the elements. Equivalent circuits were used to assess the influence of parasitic parameters. The effect of noise induced by structural elements was approximated using parallel connected transformers in short circuit mode. The simulation was carried out in the frequency range from 100 Hz to 1 GHz. As a result of the conducted research, it was obtained: taking into account the parasitic parameters of the elements leads to a significant change in the form of the ideal frequency response of the noise suppression filter; the value of the capacitance of the pass capacitor in the considered frequency range does not make a significant contribution to the attenuation introduced by the filter; in the low-frequency region, the magnitude of the inductance of the coils has the greatest influence on the output characteristic of the filter; in the high-frequency region, the radiating properties of structural elements begin to appear, the influence of which on the attenuation introduced by the filter is significant.

Anderson-Stuart Model to Analyze AC and DC Conductivity of Lithium Zinc-Silicate Glass / Glass-Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 919-924
Author(s):  
M.S. Jogad ◽  
V.K. Shrikhande ◽  
A.H. Dyama ◽  
L.A. Udachan ◽  
Govind P. Kothiyal
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Low Frequency ◽  
Frequency Region ◽  
Dc Conductivity ◽  
Frequency Range ◽  
High Frequency Region ◽  
Dc Conductivities ◽  
Conductivity Variation ◽  
Different Temperatures

AC and DC conductivities have been measured by using the real (e¢) and imaginary (e¢¢) parts of the dielectric constant data of glass and glass-ceramics (GC) at different temperatures in the rage 297-642K and in the frequency range 100 Hz to 10 MHz. Using Anderson –Stuart model, we have calculated the activation energy, which is observed to be lower than that of the DC conductivity. The analysis for glass/glass-ceramics indicates that the conductivity variation with frequency exhibits an initial linear region followed by nonlinear region with a maximum in the high-frequency region. The observed frequency dependence of ionic conductivity has been analyzed within the extended Anderson–Stuart model considering both the electrostatic and elastic strain terms. In glass/glassceramic the calculations based on the Anderson-Stuart model agree with the experimental observations in the low frequency region but at higher frequencies there is departure from measured data.

scholarly journals NOISE REDUCTION METHOD FOR OCT IMAGES BASED ON EMPIRICAL MODE DECOMPOSITION

2013 ◽  
Vol 06 (02) ◽  
pp. 1350009 ◽  
Author(s):  
OLEG O. MYAKININ ◽  
DMITRY V. KORNILIN ◽  
IVAN A. BRATCHENKO ◽  
VALERIY P. ZAKHAROV ◽  
ALEXANDER G. KHRAMOV
Keyword(s):  
Noise Reduction ◽  
Empirical Mode Decomposition ◽  
Noise Suppression ◽  
Reduction Method ◽  
Tissue Structure ◽  
Diagnostic Process ◽  
Important Process ◽  
Post Processing ◽  
Mode Decomposition ◽  
Mesh Implant

In this paper, the new method for OCT images denoizing based on empirical mode decomposition (EMD) is proposed. The noise reduction is a very important process for following operations to analyze and recognition of tissue structure. Our method does not require any additional operations and hardware modifications. The basics of proposed method is described. Quality improvement of noise suppression on example of edge-detection procedure using the classical Canny's algorithm without any additional pre- and post-processing operations is demonstrated. Improvement of raw-segmentation in the automatic diagnostic process between a tissue and a mesh implant is shown.

scholarly journals Compact D-CRLH resonator for low-pass filter with wide rejection band, high roll-off, and transmission zeros

2018 ◽  
Vol 11 (5-6) ◽  
pp. 509-516 ◽  
Author(s):  
Dilip Kumar Choudhary ◽  
Mahmoud A. Abdalla ◽  
Raghvendra Kumar Chaudhary
Keyword(s):  
Filter Design ◽  
Short Circuit ◽  
Tank Circuit ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Filter Bandwidth ◽  
Transmission Zeros ◽  
Low Pass ◽  
Lc Tank ◽  
Rejection Band

AbstractA compact low-pass filter (LPF) with wide rejection band based on T-type circuit of an enhanced dual composite right-/left-handed (D-CRLH) resonator is presented in this paper. The resonator has only one cell with series and parallel tank circuit. The parallel LC tank circuit has been realized by an interdigital capacitor and one shorted finger, whereas its series LC tank circuit is realized by an air gap capacitance and a short circuit stub. The filter has wide rejection band bandwidth with three transmission zeros (TZs). The filter bandwidth and TZs frequencies are controlled by the D-CRLH element values. The results of the proposed filter demonstrate minimum insertion loss in passband, high roll-off rate, and good figure of merit. The measured results are in good agreement with the simulated results. The detailed filter design is discussed in terms of circuit modeling, dispersion analysis, and full-wave simulation. Finally, the filter size is compact (0.10 λg × 0.15 λg) at cut-off frequency.

scholarly journals High-Frequency Modeling and Filter Design for PWM Drives with Long Cables

2020 ◽  
Author(s):  
Lei Wang ◽  
Yifan Zhang ◽  
Muhammad Saqib Ali ◽  
Guozhu Chen ◽  
Josep M. Guerrero ◽  
...  
Keyword(s):  
High Frequency ◽  
Small Volume ◽  
Filter Design ◽  
Wide Frequency Range ◽  
Drive System ◽  
Power Cables ◽  
Frequency Range ◽  
Differential Mode ◽  
Proper Filter ◽  
Peak Value

Aiming for the problems emerging in the PWM drive system with long cables, accurate modeling of power cables is the premise to predict and analyze the relevant phenomenon, and a proper filter design is the key solution to these problems. This paper proposes high-frequency cable models to represent the frequency-dependent characteristics, especially for the high-frequency resistance of the cable that is an easily overlooked factor but determines the damping of overvoltage. The proposed models can be used for accurately representing the cable parameters in a wide frequency range, and correctly simulating the differential mode (DM) overvoltage and common mode (CM) current, including the peak value, oscillation frequency and damping of the transient waveform. In addition, improved filter networks are proposed to suppress the DM voltage and CM current, with the merit of low losses, small volume and an excellent ability of suppressing overvoltage. The proposed cable models and the filter design have been validated in a 750W PWM drive system with 200m power cables.

scholarly journals Improved Turbulence Profiling with Field-Adapted Acoustic Doppler Velocimeters Using a Bifrequency Doppler Noise Suppression Method

2008 ◽  
Vol 25 (3) ◽  
pp. 452-463 ◽  
Author(s):  
D. Hurther ◽  
U. Lemmin
Keyword(s):  
Noise Reduction ◽  
Carrier Frequency ◽  
Noise Suppression ◽  
Isotropic Turbulence ◽  
Field Studies ◽  
Sample Volume ◽  
Grid Turbulence ◽  
Electronic Circuitry ◽  
Reduction Methods ◽  
Velocity Spectra

Abstract A novel noise reduction method and corresponding technique are presented for improving turbulence measurements with acoustic Doppler velocimeters (ADVs) commonly used in field studies of coastal and nearshore regions, rivers, lakes, and estuaries. This bifrequency method is based on the decorrelation of the random and statistically independent Doppler noise terms contained in the Doppler signals at two frequencies. It is shown through experiments in an oscillating grid turbulence (OGT) tank producing diffusive isotropic turbulence that a shift in carrier frequency of less than 10% is sufficient to increase the resolved frequency range by a decade in the turbulent velocity spectra. Over this spectral range, the slope of the velocity spectra agrees well with the universal inertial range value of −5/3. The limit due to spatial averaging effects over the sample volume can be determined from the abrupt deviation of the spectral slope from the −5/3 value. As a result, the relative error of the turbulent intensity estimate and the turbulent kinetic energy (TKE) dissipation rate, measured by two different methods, does not exceed 10% in the case of isotropic turbulence. Furthermore, the bifrequency method allows accurate estimates of the turbulent microscales as shown by the good agreement of the ratio between the Taylor and Kolmogorov microscales and an Re1/4t power law. Compared to previous Doppler noise reduction methods (Garbini et al.), an increase in time resolution by a factor of 4 is achieved. The proposed method also avoids the loss of TKE energy contained in isotropic flow structures of size equal to and smaller than the sample volume. Different from Doppler noise methods proposed by Hurther and Lemmin and Blanckaert and Lemmin, this method does not require additional hardware components, electronic circuitry, or sensors because the redundant instantaneous velocity field information is captured with the same transducer. The required shift in carrier frequency is small enough for the bifrequency method to be easily implemented in commercial ADVs.

scholarly journals Research on Serial VSC-LCC Hybrid HVdc Control Strategy and Filter Design Scheme

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2260
Author(s):  
Fan Cheng ◽  
Lijun Xie ◽  
Zhibing Wang
Keyword(s):  
Reactive Power ◽  
Filter Design ◽  
Control Strategies ◽  
Short Circuit ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Level Control ◽  
Hvdc System ◽  
High Voltage Direct Current ◽  
Design Scheme

This paper investigated the characteristics of a novel type of hybrid high voltage direct current (HVdc) converter, which is composed by line commutated converter series with voltage source converter. The system and valve level control strategies are introduced, which can provide ac system voltage support. A novel filter design scheme composed by resonant filers for hybrid HVdc are also proposed, which can decrease the capacity of reactive power compensation equipment without deteriorate harmonic characteristics. The ac voltage of HVdc fluctuation level caused by transmitted power variation will be effectively reduced, with the coordination between filter design scheme and converter control. In addition, the influence of ac grid strength is also analyzed by equivalent source internal impedance represented by short circuit ratio (SCR). Finally, the +800 kV/1600 MW hybrid HVdc system connecting two ac grids under different SCR cases are studied, and the PSCAD/EMTDC simulation results have validated the effectiveness for proposed strategy.

Noise Evaluation of Concrete Pavement

2013 ◽  
Vol 368-370 ◽  
pp. 1985-1989
Author(s):  
Ya Min Liu ◽  
Rao Rao Han ◽  
Zhi Jin Tao ◽  
Jie Chen
Keyword(s):  
Noise Reduction ◽  
Noise Level ◽  
Noise Spectrum ◽  
Concrete Pavement ◽  
Noise Characteristic ◽  
Groove Width ◽  
Concrete Pavements ◽  
Frequency Range ◽  
Porous Concrete ◽  
Noise Evaluation

In order to evaluate noise characteristic of concrete pavements with different texture, specimens were prepared carefully by varying groove parameters, such as groove width and space between grooves. Employing tire impact method, the noise level and noise spectrum of different pavements were analyzed. The results indicate that the noise level of transverse grooved concrete pavement is the greatest, and the followings are glossy concrete pavement and longitudinal grooved concrete pavement, porous concrete pavement has the lowest noise level. For grooved pavement, the noise level is promoted with increasing the space between grooves. Besides that, the noise level of transverse grooved concrete pavement becomes greater as the groove width increases. For longitudinal grooved pavement, there is a contrary tendency. It is porous concrete pavement for a frequency larger than 1600HZ. In the whole frequency range, the noise-reduction ability of transverse grooved concrete pavement is the worst.

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