The Viterbi algorithm (VA) for decoding convolutionally encoded data has historically been implemented on special-purpose digital electronic hardware. For short/moderate (K equals 3 to 9) constraint length codes, a pr...
详细信息
ISBN:
(纸本)081940943X
The Viterbi algorithm (VA) for decoding convolutionally encoded data has historically been implemented on special-purpose digital electronic hardware. For short/moderate (K equals 3 to 9) constraint length codes, a primary design goal is to maximize the decoded bit rate while minimizing circuit area. In recent years, a number of special-purpose architectures based upon shuffle-exchange networks, cube-connected cycles, ring-based networks, systolic arrays, or programmable processors have been designed for efficient implementation of the VA at these and longer constraint lengths. However, at the same time, the performance:cost ratio of high- end general-purpose computing machines has been improving dramatically. Recognizing the substantial investment in time and resources required to design and build an ASIC-based decoder for long (K equals 10 to 15) constraint length codes, the feasibility of implementation of the VA as a background process on a readily available general-purpose parallel processing machine deserves exploration. We consider the limitations and benefits of a Viterbi decoder for long constraint length codes implemented in software on a general-purpose parallel processing machine.
Central to `multimedia' image processing is the desire to encode computer graphics data into a standard television signal, complete with line, field, and color subcarrier synchronizing information. The numerous in...
详细信息
ISBN:
(纸本)081940943X
Central to `multimedia' image processing is the desire to encode computer graphics data into a standard television signal, complete with line, field, and color subcarrier synchronizing information. The numerous incompatibilities between television and computer display standards render this operation far less trivial than it sounds to anyone who hasn't worked with both types of signals. To simplify the task of encoding computer graphics signals into standard NTSC (North America and Japan) or PAL (most of Europe) television format for display, broadcast, or recording, TRW LSI Products Inc. has introduced the two newest members of it multimedia integrated circuit family, the TMC22090 and TMC22190 digital video encoders.
Matrix computation and signalprocessing applications can be given effective and efficient concrete forms in a systematic way if (1) the originating problems have formal and complete specifications and (2) the associa...
详细信息
ISBN:
(纸本)081940943X
Matrix computation and signalprocessing applications can be given effective and efficient concrete forms in a systematic way if (1) the originating problems have formal and complete specifications and (2) the associated algorithms and architectures emerge along individual and aggregate levels of a consistent design methodology.
This paper describes a technique for classification of 2-D discrete signals. It consists of four modules, namely the partition, representation, measurement, and the classification modules. The first of these either pa...
详细信息
ISBN:
(纸本)081940943X
This paper describes a technique for classification of 2-D discrete signals. It consists of four modules, namely the partition, representation, measurement, and the classification modules. The first of these either passes the observed signal as a whole or divides it into subregions which may or may not overlap. The representation module first computes the shift-invariant multiscale wavelet representations (MSWAR) of the reference and the observed signals and then generates a corresponding set of 1-D signatures. The measurement module extracts those vital signal features to which the decision rules of the classification module are applied. The paper presents the design and implementation of each of these modules, emphasizing theoretical background behind the design and efficiency of their implementation. Also some preliminary results have been included that demonstrate the ability of this technique to classify observed signals that are corrupted by different types of deformities.
We propose a novel technique for the least-squares reconstruction of the Fourier phase of an image from the modulo-2(pi) phase of its bispectrum. The proposed technique unwraps the given bispectral phase and reconstru...
详细信息
ISBN:
(纸本)081940943X
We propose a novel technique for the least-squares reconstruction of the Fourier phase of an image from the modulo-2(pi) phase of its bispectrum. The proposed technique unwraps the given bispectral phase and reconstructs the Fourier phase of the image iteratively through alternating projections onto two particular constraint sets: (1) the set of bispectral phase functions that differ from the given modulo-2(pi) bispectral phase by only integral multiples of 2(pi) at every sample point, and (2) the set of bispectral phase functions that correspond to deterministic signals. We formally define the above sets and their corresponding projection operators. We describe the iterative algorithm in detail, and provide experimental results to demonstrate its performance.
The direction-of-arrival (DOA) estimation problem consists in determining the angles of arrival of a number of signals impinging on a sensor array. Recently, the so-called ESPRIT method of Roy and Paulraj has received...
详细信息
ISBN:
(纸本)081940943X
The direction-of-arrival (DOA) estimation problem consists in determining the angles of arrival of a number of signals impinging on a sensor array. Recently, the so-called ESPRIT method of Roy and Paulraj has received a great deal of attention in the literature. The method employs matrix decomposition techniques, such as singular value decomposition (SVD) and generalized Schur decomposition (GSD). The computational complexity thus involved represents a serious impediment, especially when a real-time implementation is aimed for. Therefore, the aim here is to develop an ESPRIT-type algorithm which is fully adaptive and amenable to parallel implementation. By introducing adaptivity, the computational complexity per sampling period is reduced from (Omicron) (m3) to (Omicron) (m2), where m is the `problem size,' i.e., the number of antenna doublets. On a parallel processor array with (Omicron) (m2) processors, the throughput is then (Omicron) (mo), which means that the number of measurements that are processed per time unit is independent of the problem size. The algorithm is based on an adaptive SVD updating algorithm, combined with an adaptive GSD. The corresponding systolic implementation is based on the systolic SVD updating array of Moonen et al.
Discretized 2-D deconvolution problems arising, e.g., in image restoration and seismic tomography, can be formulated as 1eas squares compuaions, mm lib— Tx112 where T is often a large-scale rectangular Toeplitz-block...
详细信息
ISBN:
(纸本)081940943X
Discretized 2-D deconvolution problems arising, e.g., in image restoration and seismic tomography, can be formulated as 1eas squares compuaions, mm lib— Tx112 where T is often a large-scale rectangular Toeplitz-block matrix. We consider solving such block least squares problems by the preconditioned conjugate gradient algorithm using square nonsingular circulant-block and related preconditioners, constructed from the blocks of the rectangular matrix T. Preconditioning with such matrices allows efficient implementation using the 1-D or 2-D Fast Fourier Transform (FFT). It is well known that the resolution of ill-posed deconvolution problems can be substantially improved by regularization to compensate for their ill-posed nature. We show that regularization can easily be incorporated into our preconditioners, and we report on numerical experiments on a Cray Y-MP. The experiments illustrate good convergence properties of these FET—based preconditioned iterations.
The Volume contains 44 Conference papers. The topic covered include Toeplitz matrices, time-frequency distribution and nonstationary signals, bit-level systolic arrays and computer arithmetic, radar signalprocessing,...
详细信息
ISBN:
(纸本)0819406945
The Volume contains 44 Conference papers. The topic covered include Toeplitz matrices, time-frequency distribution and nonstationary signals, bit-level systolic arrays and computer arithmetic, radar signalprocessing, signal estimation, array processing and beamforming.
In this paper we describe aspects of an ongoing program of work aimed at the practical realization of systolic array structures to implement digital adaptive beam-forming algorithms.
ISBN:
(纸本)0819406945
In this paper we describe aspects of an ongoing program of work aimed at the practical realization of systolic array structures to implement digital adaptive beam-forming algorithms.
A new derivation of the QR-based fast recursive least squares algorithms for Toeplitz matrices is presented. algorithms for computing Q and R in the QR decomposition of the data matrix are proposed. These algorithms c...
详细信息
ISBN:
(纸本)0819406945
A new derivation of the QR-based fast recursive least squares algorithms for Toeplitz matrices is presented. algorithms for computing Q and R in the QR decomposition of the data matrix are proposed. These algorithms can be efficiently incorporated with the fast recursive least squares algorithm and can be performed only when they are needed.
暂无评论