摘要:

AbstractThe monochromatic static image can be represented as a scalar‐valued functionf(u,v), for the brightness or density at point (u,v) on the two‐dimensional coordinate space T. For the color image, the image is represented by a vector‐valued function composed of such signal components as red, green, blue or luminance, chrominance and saturation. The sampling of an image can be considered as derivation of a sequence {fi} of spatially discrete sampled values by dividing the coordinate space T. Denoting the partitioning of the coordinate space by {Si}, the sampled valuefiis a scalar or vector value, which is determined uniquely by the subimage {f(u,v) |(u,v) ϵSi}.This paper proposes a new variable rate sampling method which partitions the multidimensional coordinate space efficiently based on the vector quantization method. A high‐speed region partitioning algorithm is also shown which is based on the successive approximation vector quantization. The usefulness of the proposed method is demonstrated by simulation. Using those results, the sampling process is reformulated as the vector quantization in the coordinate space. Thus, a new development is made for the variable rate samplin

ISSN:1042-0967    

DOI:10.1002/ecjc.4430730201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractAn efficient algorithm is proposed for approximating the magnitude of the low‐pass IIR digital filter with prescribed group delay in equiripple. Prescribed group delay characteristics can be realized by placing in the denominator of the transfer function a polynomial expression designed to have such characteristics. For amplitude characteristics we approximate it to obtain equiripple using a linear‐phase polynomial in the numerator.Equiripple magnitude approximation is done separately for the passband and for the stopband and all the characteristics are made equiripple by several times of iterations.In this simple method the auxiliary complex plane is utilized and in each the transformed transfer function is expressed as the sum of objective magnitude 1 and the error function for it. By assigning an all‐pass function to an approximation function of the error function, equiripple characteristics are realized.By approximation in the stopband, good equiripple characteristics can be obtained even if all the degrees of freedom are used. On the other hand, since the approximation in the passband deviated largely from equirippleness, a method is presented for improving ripple characteristics by reducing the degree of freedom by one. As a design example, a filter of order 10 is

ISSN:1042-0967    

DOI:10.1002/ecjc.4430730202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper discusses the selection of the optimal device for LSI implementation of Viterbi decoder. The relation between the available number of gates and the performance of the decoder is described clearly. A method of reducing the number of gates for low‐and high‐speed LSI decoders, as well as their major performance, is described.To reduce the cost for LSI as the system LSI, it is important to maintain the versatility of the developed LSI. From such a viewpoint, general‐purpose, a highly efficient Viterbi decoder is considered by using a ROM and two kinds of LSI. The construction and the performance are discussed, aiming at an LSI implementation.The developed LSI operates at the frequency of 25 MHz or higher. It is applicable generally to the error correction with (N−1)/Ncoding rate. Compared with the Viterbi decoder using the same kind of LSI, the proposed LSI minimizes the number of chips and improves the speed by a factor of 1.5. By this elaboration, the device can drastically be reduced in size and cost, leading to an easier realization of a high‐speed, highly efficient and high‐gain error‐corr

ISSN:1042-0967    

DOI:10.1002/ecjc.4430730203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe baseband circuit for multilevel data transmission system was implemented by LSI using SC circuit technology. The waveform‐shaping filter, the full‐wave rectifier for clock regeneration, the narrowband filter and other circuits were constructed by SC circuits. The size and the power dissipation were reduced by constructing all filters in time‐division multiplex. The chip area and the power dissipation in the SC circuit is proportional to the total capacitance, and the total capacitance is determined by the capacitance ratio and the unit capacitance.From such a viewpoint, the narrowband filter used in the clock regeneration is constructed by multirate, and the capacitance ratio was compressed using theN‐path filter. Capacitance partitioning is applied to high‐Qfilters to suppress the capacitance ratio. Then by composing all capacitances as the integer multiples of the same unit capacitance, the desired ratio accuracy was achieved based on the unit capacitance of 0.1 pF. The problem of performance degradation due to integer capacitance ratio was minimized by the discrete approximation.When theN‐path filter is composed by the time‐division multiplex scheme, the performance may be degraded greatly due to the parasitic capacitance among wirings. This effect was analyzed and an improvement from the viewpoint of the layout was proposed. As a result, the multilevel data transmission baseband LSI was realized with the chip size of 4.3 × 4/2 mm2and the power consum

ISSN:1042-0967    

DOI:10.1002/ecjc.4430730204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractIn the probabilistic graph, SAT reliability may be defined as the probability that there exists at least one path consisting only of successful edges froms(source vertex) to every other vertex. The SDP method enumerates Boolean product terms corresponding to each of the minimal sets of edges (tree or cutset) whose success or failure results in successful or failed graph operation. The method then generates the reliability formula by transforming a Boolean sum of products into an equivalent form in which all terms are disjoint. However, this method has disadvantages in that in the process of transformation an intermediate product term should be compared with partially formed disjoint terms to determine the term to be retained or dropped, and the amount of computation time is dominated by the number of comparisons.This paper defines an optimal SAT reliability formula which is the one with a minimal number of product terms. Next, the expected property and ordering of the minimal sets for generating the optimal formula are discussed and some conditions are presented to obtain an optimal one whose number of terms is equal to the number of minimal sets. Furthermore, this paper proposes an optimal method which has a fundamental operation to enumerate spanning trees by edge reductions (open‐ or short‐circuiting) and derives an optimal formula such that the number of terms in the SAT reliability formula is equal to the number of spanning trees and each term of the formula can be determined from a spanning tree and its particular chords without use of Boolean algebra. Since every term is determined directly without comparisons at a time when a tree is generated, it seems to result in less computation time and remarkable saving of the memory space compared with the SDP method using a set of minimal cuts

ISSN:1042-0967    

DOI:10.1002/ecjc.4430730205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractIn the study of acoustic environment, the well‐known regression analysis is applied based on the measured data for the predictor variable and the criterion variable. Standard methods are employed in the usual regression analysis, such as the assumption of Gaussian distribution of the variable, the mean‐square evaluation of the error, and the prediction based on the transformation of regression function. This paper concentrates on the derivation of a new methodology, avoiding as much as possible such a traditional artificial simplification, and predicts the overall distribution of the fluctuation of the predictor variables based on the criterion variables with arbitrary fluctuation distribution. Based on the standard method of regression analysis, a discussion is made as to what higher‐order processing should be introduced to achieve the goal of prediction of the fluctuation distribution. A method of regression analysis matched to the complexity of the phenomenon, and a new prediction method for the response distribution based on the regression are proposed. More precisely, three kinds of regression models are derived which reflect as comprehensively as possible various linear and nonlinear correlation information between two kinds of variables. It is shown that the well‐known regression analysis based on the least mean‐square evaluation is included in the proposed method as a special case. The proposed regression model and the prediction method are applied to the actually measured data for the acoustic environment, indicating experimentally although partially the practical usefulness of the propos

ISSN:1042-0967    

DOI:10.1002/ecjc.4430730206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe characteristics of a microphone are affected by the pressure and composition of the ambient gas. This paper presents a numerical simulation of the microphone within nitrogen gas with various pressures up to 48 atm. The simulation was carried out both for the deflection (static deflection) of the membrane by the polarization voltage and for the vibration (dynamic deflection) of the membrane by the incident acoustic pressure. In these cases, the physical constants of the gas, the location of the hole on the back plate and the gas flow between the back plate with a hole and the membrane were considered. The case also was considered in which the location of the hole is axially nonsymmetric. It was found that the membrane vibration derived by simulation corresponds well with the experimental result on the actual microphone as reported previously. From these simulations, the sensitivity frequency response of the condenser microphone under a high‐gas‐pressure environment were better underst

ISSN:1042-0967    

DOI:10.1002/ecjc.4430730207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper proposes a method to approximate transfer functions of magnitude and delay digital equalizers for transmission channels with bandpass characteristics. In this method, an extrapolation band is added to the equalization band on the unit circle on thez‐plane, and the resulting extended approximation band is mapped on the overall unit circle on the auxiliary complex plane.In the magnitude equalization, the all‐pole type transfer function is used for the approximation to have a loss from the extended approximated band. On the auxiliary complex plane, the desired characteristics are squared and inverted. Then the extrapolation characteristics are determined, and the inverted desired characteristics are expanded into Fourier cosine series. This series is transformed inversely into thez‐plane to determine the denominator of the transfer function. If the extrapolation characteristics are determined improperly, the resulting transfer functions may become unrealizable.This paper proposes a method of determining the extrapolation characteristics so that it always gives realizable transfer functions. In the delay equalization using the auxiliary complex plane, the approximation cannot be performed in a straightforward manner. In the proposed method, the delay characteristics are treated graphically and the inverted characteristics are expanded into Fourier cosine series. After inverse transformation into thez‐plane, the inverse of the series is expanded into the Fourier series and truncated in some length to give the transfer f

ISSN:1042-0967    

DOI:10.1002/ecjc.4430730208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper shows that in a certain type of amplitude‐controlled oscillator using a pulsewidth controller, correspondence of the Poincaré map with the cut map and logistic map can be obtained. It is proven almost analytically that the Poincaré map is ergodic if it becomes a cut map. By a computer‐assisted analysis, it is proven that chaos in the sense of Li‐Yorke is generated if it is a logistic map. Further, the validity of the analysis is confirmed by a circuit exp

ISSN:1042-0967    

DOI:10.1002/ecjc.4430730209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractIt is known that the activeRCfilter which simulates theLCladder filter has lower element‐sensitivity. However, recently, many such types of filters have been proposed. In this paper, a method of realization by low‐pass filter simulation‐type activeRCcircuit is described.First, it is proposed that anLCfilter to be simulated be realized by adding resistors in parallel toL's and in series toC' s of the conventionalLCfilter. Such a filter has the transmission zeros on the negative real axis of the 5‐plane, thus the conventional transfer function can no longer be used.Next the derivation method of the transfer function for this filter will be presented. Then the realization of theLCRfilter obtained by the activeRCcircuit using a reduced number of voltage followers will be described.Finally, the synthesis and experiment of a fifth‐order Chebyshev low‐pass filter will be given. The effectiveness of the synthesis method is confirmed by the fact that the analysis of the element sensitivity by computer shows that in the passband it is below about 50 percent that of the leapfrog t

ISSN:1042-0967    

DOI:10.1002/ecjc.4430730210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY