97,095 research outputs found
Time and Frequency domain design of Functional Filters
Abstract-This paper proposes both time and frequency domain design of functional filters for linear time-invariant multivariable systems where all measurements are affected by disturbances. The order of this filter is equal to the dimension of the vector to be estimated. The time procedure design is based on the unbiasedness of the filter using a Sylvester equation; then the problem is expressed in a singular system one and is solved via Linear Matrix Inequalities (LMI) to find the optimal gain implemented in the observer design. The frequency procedure design is derived from time domain results by defining some useful Matrix Fractions Descriptions (MFDs) and mainly, establishing the useful and equivalent form of the connecting relationship that parameterizes the dynamic behavior between time and frequency domain, given by Hippe in the reduced-order case. A numerical example is given to illustrate our approach
Graph Signal Processing: Overview, Challenges and Applications
Research in Graph Signal Processing (GSP) aims to develop tools for
processing data defined on irregular graph domains. In this paper we first
provide an overview of core ideas in GSP and their connection to conventional
digital signal processing. We then summarize recent developments in developing
basic GSP tools, including methods for sampling, filtering or graph learning.
Next, we review progress in several application areas using GSP, including
processing and analysis of sensor network data, biological data, and
applications to image processing and machine learning. We finish by providing a
brief historical perspective to highlight how concepts recently developed in
GSP build on top of prior research in other areas.Comment: To appear, Proceedings of the IEE
Optimal cosine modulated nonuniform linear phase FIR filter bank design via stretching and shifting frequency response of prototype filter
This paper proposes an optimal cosine modulated nonuniform linear phase finite impulse response (FIR) filter bank design. The frequency responses of all the analysis filters and the synthesis filters of the filter bank are derived based on both stretching and shifting the frequency response of the prototype filter. The total aliasing error of the filter bank is minimized subject to a specification on the maximum amplitude distortion of the filter bank as well as specifications on both the maximum passband ripple magnitude and the maximum stopband ripple magnitude of the prototype filter. This filter bank design problem is actually a functional inequality constrained optimization problem. Our recently developed integration approach is employed for solving the problem. Computer numerical simulation results show that our proposed design method outperforms existing design methods
Highly Selective Terahertz Bandpass Filters Based on Trapped Mode Excitation
We present two types of metamaterial-based spectral bandpass filters for the
terahertz (THz) frequency range. The metamaterials are specifically designed to
operate for waves at normal incidence and to be independent of the field
polarization. The functional structures are embedded in films of
benzocyclobutene (BCB) resulting in large-area, free-standing and flexible
membranes with low intrinsic loss.
The proposed filters are investigated by THz time-domain spectroscopy and
show a pronounced transmission peak with over 80]% amplitude transmission in
the passband and a transmission rejection down to the noise level in the
stopbands. The measurements are supported by numerical simulations which
evidence that the high transmission response is related to the excitation of
trapped modes.Comment: 6 pages, 4 figure
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Variable domain transformation for linear PAC analysis of mixed-signal systems
This paper describes a method to perform linear AC analysis on mixed-signal systems which appear strongly nonlinear in the voltage domain but are linear in other variable domains. Common circuits like phase/delay-locked loops and duty-cycle correctors fall into this category, since they are designed to be linear with respect to phases, delays, and duty-cycles of the input and output clocks, respectively. The method uses variable domain translators to change the variables to which the AC perturbation is applied and from which the AC response is measured. By utilizing the efficient periodic AC (PAC) analysis available in commercial RF simulators, the circuit’s linear transfer function in the desired variable domain can be characterized without relying on extensive transient simulations. Furthermore, the variable domain translators enable the circuits to be macromodeled as weakly-nonlinear systems in the chosen domain and then converted to voltage-domain models, instead of being modeled as strongly-nonlinear systems directly
Stability analysis of electric power systems for ‘more electric’ aircraft
This paper presents a comprehensive assessment of small-signal stability for a “more-electric”
aircraft power system consisting of a synchronous variable-frequency generator which supplies several power
electronic controlled loads via an 18-pulse autotransformer rectifier unit (ATRU) for AC-DC conversion.
Functional models for key power system components and loads are derived. Numerical tools employed for the
automatic calculation of linearized equations and operating points are described, and the influence of leading
design and operational parameter on system stability is evaluated
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