| 1. |
- Gunnarsson, Svante, et al.
(författare)
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Frequency Domain Tracking Characteristics of Adaptive Algorithms
- 1989
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Ingår i: IEEE Transactions on Acoustics, Speech and Signal Processing. - : Institute of Electrical and Electronics Engineers (IEEE). - 0096-3518. ; 37:7, s. 1072-1089
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Tidskriftsartikel (refereegranskat)abstract
- The problem of tracking time-varying linear systems is discussed. The focus is on the model quality in terms of the mean square error (MSE) between the true (momentary) transfer function and the estimated one. This MSE is thus a function of frequency. The exact expression for the MSE is complicated, but simple expressions that are asymptotic in the model order are developed for model structures of finite impulse response (FIR) character. Simulations verify that these simple expressions are quite reliable and insightful even for moderate model orders. Expressions are developed for three basic adaptation algorithms (recursive identification algorithms), viz. the least-mean-squares algorithm, the recursive least-squares algorithm with exponential forgetting, and a tracking algorithm based on the Kalman filter. The results apply both to slowly time-varying systems and to the model recovery after an abrupt change in the system dynamics.
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| 2. |
- Ottersten, Björn, 1961-, et al.
(författare)
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Direction-of-Arrival Estimation for Wideband Signals using the ESPRIT Algorithm
- 1990
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Ingår i: IEEE Transactions on Acoustics, Speech and Signal Processing. - : IEEE Signal Processing Society. - 0096-3518. ; 38:2, s. 317-327
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Tidskriftsartikel (refereegranskat)abstract
- A novel direction-of-arrival estimation algorithm is proposed that applies to wideband emitter signals. A sensor array with a translation invariance structure is assumed, and an extension of the ESPRIT algorithm for narrowband emitter signals is obtained. The emitter signals are modeled as the stationary output of a finite-dimensional linear system driven by white noise. The array response to a unit impulse from a given direction is represented as the impulse response of a linear system. The measured data from the sensor array can then be seen as the output of a multidimensional linear system driven by white noise sources and corrupted by additive noise. The emitter signals and the array output are characterized by the modes of the linear system. The ESPRIT algorithm is applied at the poles of the system, the power of the signals sharing the pole is captured, and the effect of noise is reduced. The algorithm requires no knowledge, storage, or search of the array manifold, as opposed to wideband extensions of the MUSIC algorithm. This results in a computationally efficient algorithm that is insensitive to array perturbations. Simulations are presented comparing the wideband and ESPRIT algorithm to the modal signal subspace method and the coherent signal subspace method.
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| 3. |
- Taxén, Lars
(författare)
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Polyphase filter banks using wave digital filters
- 1981
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Ingår i: IEEE Transaction on Acoustics, Speech and Signal Processing. - : IEEE. - 0096-3518. ; 29:3, s. 423-428
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Tidskriftsartikel (refereegranskat)abstract
- The branch filters in a digital polyphase network can be designed either as FIR filters by decomposing the impulse response of an FIR low-pass prototype filter, or as o r d i i IIR filters by the synthesis method of Bellanger. The use of all-pass networks has hitherto been considered unfeasible because of the associated computational difficulties involved in the design of filter banks with many branches. The purpose of this paper is to demonstrate that it is indeed possible to design the branch filters as all-pass-low-pass sections without the need of a prototype filter. Moreover, these sections can be realized as wave digital filters, which give improved properties over the other designs with respect to hardware requirements, group delay, sensitivity, dynamics and limit cycles. Examples, including the design of the practically important 60-channel filter bank for the transmultiplexer, are given
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| 4. |
- Viberg, Mats
(författare)
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Sensor Array Processing using Gated Signals
- 1989
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Ingår i: IEEE Transactions on Acoustics, Speech and Signal Processing. - : IEEE Signal Processing Society. - 0096-3518. ; 37:3, s. 447-450
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Tidskriftsartikel (refereegranskat)abstract
- The author considers the problem of using an array of sensors for separating a desired signal from unwanted disturbance signals. The desired signal is assumed to be gated, either in time or in frequency. He derives an eigenstructure based method which requires no knowledge of the array manifold and which allows for coherent signals
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| 5. |
- Wahlberg, Bo, 1959-
(författare)
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ARMA spectral estimation of narrow-band processes via model reduction
- 1990
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Ingår i: IEEE Transactions on Acoustics, Speech, and Signal Processing. - : Institute of Electrical and Electronics Engineers (IEEE). - 0096-3518. ; 38:7, s. 1144-1154
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Tidskriftsartikel (refereegranskat)abstract
- The problem of estimating autoregressive moving average (ARMA) models for narrowband processes is considered. The following approach is proposed. Estimate a high-order autoregressive (AR) approximation of the process. By model reduction, based on a truncated internally balanced realization or optimal Hankel-norm model reduction, reduce the order of this high-order AR estimate to find a lower-order ARMA model. This algorithm gives ARMA spectral estimates with excellent resolution properties, without using iterative numerical minimization methods as for the maximum-likelihood method. How to take the narrowband assumption into account in the model reduction step is discussed in detail.
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