The problem of blind equalization of MIMO (multiple-input nultiple-output) communications channels is considered using the second-order statistics of the data. Such models arise when a single receiver data from multip...
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ISBN:
(纸本)0819429163
The problem of blind equalization of MIMO (multiple-input nultiple-output) communications channels is considered using the second-order statistics of the data. Such models arise when a single receiver data from multiple sources is fractionally sampled (assuming that there is excess bandwidth), or when an antenna array is used with or without fractional sampling. We focus on direct design of finite-length MMSE (minimum mean-square error) blind equalizers. We allow infinite impulse response (IIR) channels. Our approaches also work when the "subchannel" transfer functions have common zeros so long as the common zeros are minimum-phase zeros. We only require that the there exist a causal, stable left inverse (not necessarily unique) to the MIMO transfer function and that the leading coefficient matrix of the MIMO channel impulse response have its rank equal to the number of sources. The channel length or model orders need not be known. The sources are recovered up to a unitary mixing matrix and are further 'unmixed' using higher-order statistics of the data. An illustrative simulation example is provided.
An innovative approach is being used to implement and simulate the infrared (IR) and laser radar signalprocessingalgorithms for the advanced Sensor Technology Program (ASTP) and the Discrimination Interceptor Techno...
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ISBN:
(纸本)0819428221
An innovative approach is being used to implement and simulate the infrared (IR) and laser radar signalprocessingalgorithms for the advanced Sensor Technology Program (ASTP) and the Discrimination Interceptor Technology Program (DITP). Although the algorithms will run on four different computer architectures, they will use the same source code for all implementations. The initial development and testing will occur in Mathcad on a Windows 95/NT personal computer, then move to simulation on a Silicon Graphics (SGI) workstation, then to scaled real-time simulation on a parallel high performance computer (HPC), and finally to the actual flight processor, the miniaturized parallel Wafer Scale signal Processor (WSSP) with a MIMD (multiple-instruction and multiple data) architecture. This flexibility is accomplished with code wrappers that implement interchangeable interface layers for the code modules, one wrapper for Mathcad matrices, one for C++ objects on the workstation, one for message passing with static routing on the HPC, and one for dynamically routed message passing on the WSSP. With this approach, developers can move modules back and forth from the workstation simulation environment to the implementation hardware. This will eliminate the need to maintain different versions of the same algorithm. The signalprocessingalgorithms will be modified to work in a massively parallel architecture, with a message passing interface, which is simulated on the Silicon Graphics workstation, emulated on the HPC, and implemented on the WSSP. This approach will allow for pipeline processing as well as multiple, concurrently running instances of modules. In addition, innovative algorithms will fuse active laser radar detections and passive multicolor IR sensor measurements to improve target state estimation.
We present the "direct inverse scale transform" which is the extension to the "direct scale transform" method originally proposed by Williams, Zalubas and Hero III (see advancedsignalprocessing A...
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We present the "direct inverse scale transform" which is the extension to the "direct scale transform" method originally proposed by Williams, Zalubas and Hero III (see advanced signal processing algorithms, architectures and implementations VI, SPIE, vol.2846, p.262-72, 1996). This scheme completes the calculation of analysis and synthesis equations for the scale transform pair which is suitable especially for non-integer values of dilation or compression of signals. Several examples of transformed and reconstructed synthetic and real 1-D and 2-D signals are included.
System developers have found that exploiting parallel architectures for control systems is challenging and often the resulting implementations do not provide the expected performance advantages over traditional unipro...
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The proceeding contains 53 papers from the conference of SPIE advanced VIII signalprocessing: algorithms, architectures, and implementations. The topics:include pattern recognition under translation and scale changes...
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The proceeding contains 53 papers from the conference of SPIE advanced VIII signalprocessing: algorithms, architectures, and implementations. The topics:include pattern recognition under translation and scale changes, instanteous frequency of a propagating pulse;data-driven time-frequency and time-scale detectors;time-varying frequencies of a signal;circulant preconditioners from B-splines;extensions to total variation denoising and Jacobi method for signal subspace computation.
We calculate the instantaneous frequency at a fixed position of a propagating pulse in the asymptotic regime. We also discuss the multimode case and relate it to the concept of instantaneous bandwidth.
ISBN:
(纸本)0819425842
We calculate the instantaneous frequency at a fixed position of a propagating pulse in the asymptotic regime. We also discuss the multimode case and relate it to the concept of instantaneous bandwidth.
This paper presents, Index Mapping, a technique to efficiently map a widely used class of digital signalprocessingalgorithms onto a space/time paradigm with immediate representation as the partitioning and schedulin...
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ISBN:
(纸本)0819425842
This paper presents, Index Mapping, a technique to efficiently map a widely used class of digital signalprocessingalgorithms onto a space/time paradigm with immediate representation as the partitioning and scheduling map of a small, I/O efficient, hardware array. When applied to reconfigurable FPGA based hardware architectures with downstream Sea-of-Gates optimization methods, the resulting systems form a dynamic signalprocessing environment with the best mix of performance and flexibility for wireless applications. Herein, Index Mapping is demonstrated with a mapping of the Fast Fourier Transform (FFT) onto an FPGA computing machine, the ReConfigurable Processor (RCP).
Impulsive transient signals have been difficult to characterize and classify using traditional signalprocessing methods. We show that time-frequency distributions can effectively characterize the transient response o...
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ISBN:
(纸本)0819425842
Impulsive transient signals have been difficult to characterize and classify using traditional signalprocessing methods. We show that time-frequency distributions can effectively characterize the transient response of an acoustical cavity. Class-dependent kernels developed from time-frequency distributions are used to successfully classify the impulsive transients.
This brief presents efficient single-rate architectures for the one-dimensional orthonormal discrete wavelet transform (DWT). This brief makes two contributions, First, we show that architectures that are based on the...
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This brief presents efficient single-rate architectures for the one-dimensional orthonormal discrete wavelet transform (DWT). This brief makes two contributions, First, we show that architectures that are based on the quadrature mirror filter (QMF) lattice structure require approximately half the number of multipliers and adders than corresponding direct-form structures. Second, we present techniques for mapping the 1-D orthonormal DWT to folded and digit-serial architectures which are based on the QMF lattice structure. For folded architectures, we discuss two techniques for mapping the QMF lattice structure to hardware. For digit-serial architectures, we show that any two-channel subband system can be implemented using digit-serial processing techniques by utilizing the polyphase decomposition Using this result, we describe an orthonormal DWT architecture which uses the QMF lattice structure and digit-serial processing techniques, The proposed folded and digit-serial QMF lattice structures are attractive choices for implementations of the orthonormal DWT which require low area and low power dissipation.
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