Projektiranje svepolnih aktivnih RC filtara niskog šuma pomoću optimiranih bikvadratnih sekcija

In this paper it is shown that active-RC filters can be designed to have low-sensitivity to passive components and at the same time possess low output thermal noise. The design procedure of low-noise and low-sensitivity, positive-feedback, second- and third-order low-pass allpole filters, using impedance tapering, has already been published. The noise analysis in this paper was extended to the high-pass and band-pass filters and those with negative-feedback. The optimum designs, regarding both noise and sensitivity of most useful filter sections were summarized in the table form (as a cookbook) and demonstrated on examples. The classical methods were used to determine output noise spectral density and total rms output noise of filters. It was found that low-sensitivity filters with minimum noise have reduced resistance levels, low Q-factors, low-noise operational amplifiers and use impedance tapering design.U ovom radu je prikazano da optimalne aktivne RC filtarske sekcije s niskim osjetljivostima na varijacije pasivnih komponenata istovremeno imaju nizak nivo termičkog šuma na izlazu. Postupak projektiranja nisko osjetljivih i nisko šumnih, nisko-propusnih filtarskih sekcija drugog i trećeg reda s pozitivnom povratnom vezom pomoću ’skaliranja impedancija’ je već objavljen. U ovom radu je analiza izlaznog šuma proširena na nove sekcije koje realiziraju pojasno-propusnu i visoko-propusnu frekvencijsku karakteristiku kao i na sekcije koje koriste negativnu povratnu vezu u realizaciji. Svi postupci optimalnog projektiranja u smislu niskog šuma i niske osjetljivosti za najreprezentativnije filtarske sekcije su sažeti i raspoloživi u obliku tablica s postupkom projektiranja ’korak po korak’ (kuharica) te pokazani na primjerima. U istraživanju su korištene klasične metode za određivanje spektralne gustoće šuma i totalne efektivne vrijednosti šuma na izlazu filtara. Pokazano je da filtri sa niskim osjetljivostima koji istovremeno imaju nizak nivo šuma posjeduju niske vrijednosti otpora, realiziraju niske Q faktore, koriste niskošumna operacijska pojačala u realizaciji te su projektirana metodom skaliranja impedancija

Projektiranje svepolnih aktivnih RC filtara niske osjetljivosti pomoću optimiranih bikvadratnih sekcija

In this paper we present an optimal design procedure for second- and third-order active resistance-capacitance (RC) single-amplifier building blocks that are used to build a high-order tolerance-insensitive allpole filter. The design procedure of low-sensitivity, low-pass second- and third-order active-RC allpole filters, with positive feedback, has already been published. The design was extended to the high-pass and band-pass filters, as well as, to the filters using negative feedback. In this paper we summarize all these previously presented designs in the form of a tabulated step-by-step design framework (cookbook). The low passive sensitivity of the resulting circuits, as well as low active sensitivity features are demonstrated on the high-order Chebyshev filter examples. The resulting low passive sensitivity is investigated using the Schoeffler sensitivity measure, whereas the low active sensitivity is investigated with Matlab using finite and frequency dependent opamp gain.Prikazan je optimalan postupak projektiranja aktivnih RC filtarskih sekcija drugog i trećeg reda bez konačnih nula s jednim pojačalom koje se koriste pri građenju filtara visokog reda s niskom osjetljivošću. Postupak projektiranja nisko osjetljivih, nisko propusnih filtara već je objavljen, a u ovome je radu navedeni postupak proširen na nove sekcije koje realiziraju pojasno propusnu i visoko propusnu frekvencijsku karakteristiku kao i na sekcije koje koriste negativnu povratnu vezu u realizaciji. Svi su postupci optimalnog projektiranja sažeti i raspoloživi u obliku tablica s postupkom projektiranja “korak po korak”. Niska osjetljivost na tolerancije pasivnih komponenata, kao i niska osjetljivost na varijacije aktivnog elementa (pojačala) pokazani su na primjerima projektiranja Chebyshevljevih filtara visokog reda. Pritom ostvarena niska osjetljivost, kako pasivna tako i aktivna, istraživane su pomoću Shefflerove mjere osjetljivosti, odnosno uporabom frekvencijski ovisnog modela operacijskog pojačala u simulaciji pomoću programa Matlab

Optimizirani NP i PP filtri drugog i četvrtog reda

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

Applications of MATLAB in Science and Engineering

The book consists of 24 chapters illustrating a wide range of areas where MATLAB tools are applied. These areas include mathematics, physics, chemistry and chemical engineering, mechanical engineering, biological (molecular biology) and medical sciences, communication and control systems, digital signal, image and video processing, system modeling and simulation. Many interesting problems have been included throughout the book, and its contents will be beneficial for students and professionals in wide areas of interest

Afar, Ethiopia: a local seismic survey

A network of four independently-recording seismic stations was operated by the University of Durham in South-Central Afar during 1973 and 1974. Each station consisted of a three-component set of seismometers, whose signals were recorded on to magnetic tape. This study concerns local earthquakes recorded from February to September, 1974.250 earthquakes were located from relative arrival times of P and S phases using an optimized, laterally homogeneous, 4-layer structural model. Upper crustal P-wave velocities are found to be 4.4±0.2 km s(^-1) (0 to 4.5 km depth) and 6.2± 0.1 km s(^-1) (4.5 to 11 km). Deeper structure is poorly constrained. Anomalous upper mantle exists, with low seismic velocity (Vp about 7.4 km s(^-1)) and raised Poisson's ratio (0.31). S(_n) is transmitted, 8.0 km s(^-1) upper mantle cannot exist above about 43 km depth. Earthquake focal depths within Afar do not exceed 5 km. Epicentres correlate well with Recent axial volcanism. Spatial epicentral patterns reflect intense regional NW-SE extensional faulting. One line of epicentres shows the NNE-SSW trend of the Main Ethiopian rift. Focal mechanisms are very poorly constrained, but are consistent with NW-SE strike-slip or normal faulting, or with NE-SW dextral transcurrent faulting. Signal duration magnitude and Richter local magnitude scales are defined for Afar, Frequency-magnitude b-coefficient values are 0.87+0.05, The three-component records are polarization filtered, a technique previously applied only to teleseisms. The performance of the filters is discussed. Azimuths and apparent angles of incidence of events are determined from their first arrivals at a single recording station. Hypocentres are then obtained by ray tracing. Earthquake frequency spectra are computed through the fast Fourier transform. The spectra are dominated by the effects of the superficial crust below the receivers. Crustal transfer ratios are discussed. Increased attenuation is demonstrated below the Tendaho graben. Seismic source parameters are calculated using BRUNE's (1970) method. All results are consistent with diffuse NE-SW crustal extension. It is concluded that well-defined spreading axes do not yet exist

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion

Middle Atmosphere Program. Handbook for MAP, volume 28

Extended abstracts from the fourth workshop on the technical and scientific aspects of MST (mesosphere stratosphere troposphere) radar are presented. Individual sessions addressed the following topics: meteorological applications of MST and ST radars, networks, and campaigns; dynamics of the equatorial middle atmosphere; interpretation of radar returns from clear air; techniques for studying gravity waves and turbulence; intercomparison and calibration of wind and wave measurements at various frequencies; progress in existing and planned MST and ST radars; hardware design for MST and ST radars and boundary layer/lower troposphere profilers; signal processing; and data management

Extensible Architecture for Superconducting Quantum Computing

Quantum computing architectures with ten or more quantum bits (qubits) have been implemented using trapped ions and superconducting devices. The next milestone in the quest for a quantum computer is the realization of quantum error correction codes. Such codes will require a large number of qubits that must be controlled and measured by means of classical electronics. This scaling up leads to a number of problems and sources of error that must be accounted for in order to have an operational system. One architectural aspect requiring immediate attention is the realization of a suitable interconnect between the quantum and classical hardware. Our proposed solution to this wiring problem is the quantum socket, a three-dimensional wiring method for qubits with superior performance as compared to two-dimensional methods based on wire bonding. The quantum socket also provides a means to counteract another scaling problem, the coupling of qubits to unwanted cavity modes resulting in coherent leakage error. By following our proposed wiring methodologies, half-wave fencing or antinode pinning, we show how the error due to leakage can be mitigated to orders of magnitude below current state-of-the-art error probabilities