This paper presents an application of formal mathematics to create a high performance, low power architecture for time-frequency and time-scale computations implemented in asynchronous circuit technology that achieves...
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ISBN:
(纸本)0819429163
This paper presents an application of formal mathematics to create a high performance, low power architecture for time-frequency and time-scale computations implemented in asynchronous circuit technology that achieves significant power reductions and performance enhancements over more traditional approaches. Utilizing a combination of concepts from multirate signalprocessing and asynchronous circuit design, a case study is presented dealing with a new architecture for the fast Fourier transform, an algorithm that requires globally shared results. Then, the generalized distributive law is presented as an important paradigm for advanced asynchronous hardware design.
This paper addresses the problem of mobile radio propagation channel modeling and underlines the need for further research in this domain. The paper first describes three characteristics of the mobile radio propagatio...
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ISBN:
(纸本)0819412767
This paper addresses the problem of mobile radio propagation channel modeling and underlines the need for further research in this domain. The paper first describes three characteristics of the mobile radio propagation channel which are the propagation-path loss, the time-varying aspect, and the multipath characteristics. It then describes the properties and limitations of the present methods used for channel modeling. The main limitation concerns the non-stationary aspect of the mobile radio propagation channel. Two signalprocessing approaches are proposed to remedy the problem. Finally, the paper addresses the definition of validation criteria in order to evaluate and quantify the accuracy of each proposed model.
Detection and classification of cyclostationary signals in noise of unknown distribution is addressed and novel tests for cyclostationarity are proposed. Both cases of known and unknown signal statistics are considere...
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ISBN:
(纸本)081940943X
Detection and classification of cyclostationary signals in noise of unknown distribution is addressed and novel tests for cyclostationarity are proposed. Both cases of known and unknown signal statistics are considered. The proposed approaches exploit the asymptotic normality of sample cyclic- cumulant and polyspectrum estimators for deriving asymptotically optimal X2 tests. Simpler, but generally suboptimal versions are also presented. Simulations are performed to test the proposed algorithms and illustrate their insensitivity to any stationary noise as well as the ability of higher-than second-order schemes to suppress cyclostationary Gaussian interferences of unknown covariance.
Variants of the Winograd FFT algorithm for prime transform size are derived that offer options as to operational counts and arithmetic balance. Their implementations on VAX, IBM 3090 VF, and IBM RS/6000 are discussed....
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Variants of the Winograd FFT algorithm for prime transform size are derived that offer options as to operational counts and arithmetic balance. Their implementations on VAX, IBM 3090 VF, and IBM RS/6000 are discussed. For processors that perform floating-point addition, floating-point multiplication, and floating-point ''multiply-add'' with the same time delay, variants of the FFT algorithm have been designed such that all floating-point multiplications can be overlapped by using ''multiply-add.'' The use of a tensor product formulation, throughout, gives a means for producing variants of algorithms matching to computer architectures.
The sequence of Givens rotations used to update the upper triangular matrix R in a recursive QR decomposition may also be used to update the inverse transpose matrix R-H. Alternative forms of square-root-free Givens r...
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ISBN:
(纸本)0819412767
The sequence of Givens rotations used to update the upper triangular matrix R in a recursive QR decomposition may also be used to update the inverse transpose matrix R-H. Alternative forms of square-root-free Givens rotation for updating the inverse transpose matrix are derived by representing and storing it in a different factorized form from that used before. The modified Givens rotations do not involve explicit division by the exponential forget factor and lead to an update algorithm equivalent to the one derived by Sakai using Recursive Modified Gram Schmidt orthogonalization.
A direction-finding algorithm employing the technique of array manifold interpolation is proposed for the estimation of directions-of-arrival of multiple narrow-band sources. The algorithm is formulated by applying ar...
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ISBN:
(纸本)081940943X
A direction-finding algorithm employing the technique of array manifold interpolation is proposed for the estimation of directions-of-arrival of multiple narrow-band sources. The algorithm is formulated by applying array manifold interpolation to an ESPRIT-type method. As a result, a virtual array can be interpolated from the data collected from a real array, thereby eliminating the need for two identical arrays as in ESPRIT. Moreover, only a single interpolation matrix for the entire field-of-view is required, thus significantly reducing the computational load of the sector-divided interpolation scheme. Simulation results are provided to show the effectiveness of the proposed algorithm.
作者：
Kung, HTSuter, BWHarvard Univ
Div Engn & Appl Sci Cambridge MA USA USAF
Res Lab Ctr Integrated Transmiss & Exploitat Rome NY USA
We consider communications and network systems whose properties are characterized by the gaps of the leading eigenvalues of A(H) A for some matrix A. We show that a sufficient and necessary condition for a large eigen...
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ISBN:
(纸本)0819454974
We consider communications and network systems whose properties are characterized by the gaps of the leading eigenvalues of A(H) A for some matrix A. We show that a sufficient and necessary condition for a large eigen-gap is that A is a "hub" matrix in the sense that it has dominant columns. We describe an application of this dominant covering theory in multiple-input and multiple-output (MIMO) wireless systems.
Coupled digital phase-locked loops (CDPLLs), derived from extended Kalman filter theory, have been shown to suppress adjacent and co-channel interferers. This paper addresses the ability of these CDPLLs to separate co...
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ISBN:
(纸本)081940943X
Coupled digital phase-locked loops (CDPLLs), derived from extended Kalman filter theory, have been shown to suppress adjacent and co-channel interferers. This paper addresses the ability of these CDPLLs to separate co-channel signals. State observability criteria are defined and examined for non-linear state observations which model phase modulation. These metrics can then be used to address signal separation and tracking behavior of CDPLLs.
We discuss applications of time-frequency analysis to the investigation of astronomical type signals. In particular, we apply time-frequency techniques to a data set consisting of the kinetic energy in the three body ...
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ISBN:
(纸本)0819425842
We discuss applications of time-frequency analysis to the investigation of astronomical type signals. In particular, we apply time-frequency techniques to a data set consisting of the kinetic energy in the three body problem We explain how the methods of time-frequency analysis shed light on these signals and also how the concept of multicomponent signals is applied to their decomposition. We also discuss methods to do simple filtering and estimation of the signal parameters.
When a continuous-time signal is sampled at a rate less than the Nyquist criterion, the signal is aliased. This distortion is usually irrecoverable. However, we show that for certain AM-FM signals, the distortion due ...
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ISBN:
(纸本)0819454974
When a continuous-time signal is sampled at a rate less than the Nyquist criterion, the signal is aliased. This distortion is usually irrecoverable. However, we show that for certain AM-FM signals, the distortion due to aliasing can be mitigated and an unaliased version of the signal can be recovered from its aliased samples. We present a method for determining whether or not a signal has potentially been distorted by aliasing and an algorithm for recovering an unaliased version of the signal. The method is based on the manifestation of aliasing in the time-frequency plane, and estimating the instantaneous phase/frequency of the aliased signal.
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