5 results
Search Results
2. A New Approach to Modeling Multiport Systems from Frequency-Domain Data.
- Author
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Lefleriu, Sanda and Antoulas, Athanasios C.
- Subjects
- *
FREQUENCY response , *ALGORITHMS , *MATRIX pencils , *INTERPOLATION , *COMPUTER terminals , *COMPUTER simulation - Abstract
This paper addresses the problem of modeling systems from measurements of their frequency response. For multiport devices, currently available techniques are expensive. We propose a new approach which is based on a system-theoretic tool, the Loewner matrix pencil constructed in the context of tangential interpolation. Several implementations are presented. They are fast, accurate, they build low order models and are especially designed for a large number of terminals. Moreover, they identify the underlying system, rather than merely fitting the measurements. The numerical results show that our algorithms yield smaller models in less time, when compared to vector fitting. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
3. High-Resolution ARMA Estimation of Mixed Spectra.
- Author
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Khanshan, Amir H., Amindavar, Hamidreza, and Bakhshi, Hamidreza
- Subjects
- *
SPECTRUM analysis , *BOX-Jenkins forecasting , *WHITE noise theory , *INTERPOLATION , *SINUSOIDAL projection (Cartography) , *ESTIMATION theory , *ALGORITHMS , *COMPUTER simulation - Abstract
In this paper, we propose a high-resolution autoregressive moving average (ARMA) modeling technique for signals which are a sum of sinusoids embedded in colored noise. The approach is based on a special ARMA model. We show that an approximation to this model can be found through the central solution of Nevanlinna-Pick interpolation. In this context, it can reach a very fine resolution with a special arrangement of filterbank poles. A very efficient iterative algorithm will then be presented to achieve such desired arrangement. We also derive theoretical expressions for the variance of interpolation values for both continuous and mixed spectra for complex poles. Computer simulations show that the approach is very powerful in joint power spectrum and frequency estimation and provides superior performance with respect to traditional techniques. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
4. Effect and Compensation of Symbol Timing Offset in OFDM Systems With Channel Interpolation.
- Author
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Dah-Chung Chang
- Subjects
- *
ALGORITHMS , *SIMULATION methods & models , *COMPUTER simulation , *LINE receivers (Integrated circuits) , *ESTIMATION theory , *INTERPOLATION - Abstract
Symbol timing offset (STO) can result in intersymbol interference (ISI) and a rotated phase which value is proportional to the subcarrier index at the FFT output in an OFDM receiver. In order to avoid ISI, the FFT window start position has to be put in advance of the estimated point obtained by coarse STO estimation algorithms. But a large number of forward-shift samples will deteriorate the estimation of data subcarrier channels requiring interpolation from pilot subcarrier channels due to the phase rotation caused by a residual STO. In this paper we analyze the influence of STO on channel interpolation and propose a new compensation method for channel correction with STO. From the performance analysis of simulation results in the DVB-T application, the new algorithm not only has a better performance but also is attractive in using a simple residual STO estimation method such that few pilots are required for fine STO estimation compared to conventional approaches. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
5. A Spline-Based Algorithm for Continuous Time-Delay Estimation Using Sampled Data.
- Author
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Viola, Francesco and Walker, William F.
- Subjects
- *
ALGORITHMS , *ULTRASONIC imaging , *ESTIMATION theory , *BLOOD flow , *INTERPOLATION , *COMPUTER simulation - Abstract
Time delay estimation (TDE) lies at the heart of signal processing algorithms in a broad range of application areas, including communications, coherent imaging, speech processing, and acoustics. In medical ultrasound for example, TDE is used in blood flow estimation, tissue motion measurement, tissue elasticity estimation, phase aberration correction, and a number of other algorithms. Because of its central significance, TDE accuracy, precision, and computational cost are of critical importance. Furthermore, because TDE is typically performed au sampled signals—and delay estimates are usually desired over a continuous domain—time delay estimator performance should be considered in conjunction with associated interpolation. In this paper we present a new time-delay estimator that directly determines continuous time-delay estimates from sampled data. The technique forms a spline-based, piecewise continuous representation of the reference signal then solves for the minimum of the sum squared error between the reference and the delayed signals to determine their relative time delay. Computer simulation results clearly show that the proposed algorithm significantly outperforms other algorithms in terms of jitter and bias over a broad range of conditions. We also describe a modified version of the algorithm that includes companding with only a minor increase in computational cost. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
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