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1994 Vol. 16, No. 4
Display Method:
1994, 16(4): 337-344.
Abstract:
A multipath search algorithm of CVSD is proposed. It is shown both analytically and by simulations that the proposed multipath algorithm can overcome the unstability problem of the single-path algorithm and improve greatly the performances of the single- path algorithm. The proposed algorithm provides with a new way for further developing the high-performance speech-coding technology.
A multipath search algorithm of CVSD is proposed. It is shown both analytically and by simulations that the proposed multipath algorithm can overcome the unstability problem of the single-path algorithm and improve greatly the performances of the single- path algorithm. The proposed algorithm provides with a new way for further developing the high-performance speech-coding technology.
1994, 16(4): 345-351.
Abstract:
The minimum squared Euclidean distance (MSED) of 2-ary multi-h continuous-phase frequency-shift keying (CPFSK) signal is presented. The signal segregation degree (SSD) has been put forward to determine MSED of CPFSK. In order to maximizing MSED, SSD should be as large as possible. The full and essential conditions of maximizing SSD Ns are derived. Finally, SSD N, and the exact formulae for the MSED of 2-ary 2-h CPFSK are also presented.
The minimum squared Euclidean distance (MSED) of 2-ary multi-h continuous-phase frequency-shift keying (CPFSK) signal is presented. The signal segregation degree (SSD) has been put forward to determine MSED of CPFSK. In order to maximizing MSED, SSD should be as large as possible. The full and essential conditions of maximizing SSD Ns are derived. Finally, SSD N, and the exact formulae for the MSED of 2-ary 2-h CPFSK are also presented.
1994, 16(4): 352-358.
Abstract:
A neural network model for computing real zeros of polynomials is presented. Both the mathematical analysis and the experimental results show that the proposed network is effective.
A neural network model for computing real zeros of polynomials is presented. Both the mathematical analysis and the experimental results show that the proposed network is effective.
1994, 16(4): 359-364.
Abstract:
This paper discusses the distinction between internetworks and single network in the congestion control. It has shown the reason why all of single network s congestion controls are not suitable to internetworks. A new congestion control scheme for internetworks is presented which uses the acknowledgments of the timeouts and the feedback signal from the gateway as the indications of packet loss and congestion. Using a black-box model of the internetworks, the author derives several approximate calculating formulas and proves the schemes special characters by computer simulation. It is shown that the presented method is better than R. Jains method(1986).
This paper discusses the distinction between internetworks and single network in the congestion control. It has shown the reason why all of single network s congestion controls are not suitable to internetworks. A new congestion control scheme for internetworks is presented which uses the acknowledgments of the timeouts and the feedback signal from the gateway as the indications of packet loss and congestion. Using a black-box model of the internetworks, the author derives several approximate calculating formulas and proves the schemes special characters by computer simulation. It is shown that the presented method is better than R. Jains method(1986).
THE UNIFIED THEORY FOR DESIGNING AND ANALYSING BOTH SYNCHRONOUS AND ASYNCHRONOUS SEQUENTIAL CIRCUITS
1994, 16(4): 365-372.
Abstract:
The paper discusses general expresses of the clock signal and the next state equations containing the clock signal for flip-flops, and based on it, the unified theory for designing and analysing both synchronous and asynchronous sequential circuits is proposed. The theory is proved effective by practical examples.
The paper discusses general expresses of the clock signal and the next state equations containing the clock signal for flip-flops, and based on it, the unified theory for designing and analysing both synchronous and asynchronous sequential circuits is proposed. The theory is proved effective by practical examples.
1994, 16(4): 373-379.
Abstract:
An aperture design technique using multi-step amplitude quantization for two-dimensional solid-state active phased arrays to achieve low sidelobe is described. It can be applied to antennas with the arbitrary complex aperture. Also, the gain drop and the sidelobe degradation due to random amplitude and phase errors and element (or T/R module) failures are investigated.
An aperture design technique using multi-step amplitude quantization for two-dimensional solid-state active phased arrays to achieve low sidelobe is described. It can be applied to antennas with the arbitrary complex aperture. Also, the gain drop and the sidelobe degradation due to random amplitude and phase errors and element (or T/R module) failures are investigated.
1994, 16(4): 380-387.
Abstract:
Based on the calculation of the characteristic parameters of curved surface dipoles by moment method, the directivities are optimized, the maximum directivities of curved surface dipoles are obtained.
Based on the calculation of the characteristic parameters of curved surface dipoles by moment method, the directivities are optimized, the maximum directivities of curved surface dipoles are obtained.
1994, 16(4): 388-394.
Abstract:
By studying the arbitrary two dimensional problems of EMF in Cartesian coordinates with the numerical mode matching method, this paper presents a series of more general and applicable formulation, including the unified matrix expanding formula suitable for any source excitation. In discussing the computation method, triangular bases are chosen and its advantages are pointed out. A formula of determining grid points is prsented. As an example, a typical problem in the Electromagnetic Propagation Tool (EPT) is solved in different ways by using the proposed theory and methods. The present results agree with the ones in the literature.
By studying the arbitrary two dimensional problems of EMF in Cartesian coordinates with the numerical mode matching method, this paper presents a series of more general and applicable formulation, including the unified matrix expanding formula suitable for any source excitation. In discussing the computation method, triangular bases are chosen and its advantages are pointed out. A formula of determining grid points is prsented. As an example, a typical problem in the Electromagnetic Propagation Tool (EPT) is solved in different ways by using the proposed theory and methods. The present results agree with the ones in the literature.
1994, 16(4): 395-401.
Abstract:
Based on the materials mainly got from the National Natural Science Fundation of China supported projects, the histroy, current situation and prospect of electromagnetic field investigation in China are summarized.
Based on the materials mainly got from the National Natural Science Fundation of China supported projects, the histroy, current situation and prospect of electromagnetic field investigation in China are summarized.
1994, 16(4): 402-406.
Abstract:
The numerical simulation of two dimensional device is conducted to describe the mechanism of the special substrate current and degradation of submi-cron LDD structure observed in experiments, and finally, the optimum processes for submicron LDD CMOS are proposed.
The numerical simulation of two dimensional device is conducted to describe the mechanism of the special substrate current and degradation of submi-cron LDD structure observed in experiments, and finally, the optimum processes for submicron LDD CMOS are proposed.
1994, 16(4): 407-411.
Abstract:
Based on the statistical optimization method of circuit design centering proposed by Soin and Spence (1980), a modified yield maximization technique, moving center of gravity, is suggested. This method is satisfactory in solving circuit yield maximization when the circuit initial yield is zero. The two modified strategies are given. Finally, in order to show feasibility and usability of this method, examples of the TV circuit (CS54E-3-R) and IC(XD1531) optimal yield are given.
Based on the statistical optimization method of circuit design centering proposed by Soin and Spence (1980), a modified yield maximization technique, moving center of gravity, is suggested. This method is satisfactory in solving circuit yield maximization when the circuit initial yield is zero. The two modified strategies are given. Finally, in order to show feasibility and usability of this method, examples of the TV circuit (CS54E-3-R) and IC(XD1531) optimal yield are given.
1994, 16(4): 412-415.
Abstract:
The cyclic codes are studied by using the geometric method. It is proved that the parity check matrix for BCH code is a representation form in the eigenvector basis. Thus the study on cyclic codes may be brought into the framework of linear system theory.
The cyclic codes are studied by using the geometric method. It is proved that the parity check matrix for BCH code is a representation form in the eigenvector basis. Thus the study on cyclic codes may be brought into the framework of linear system theory.
1994, 16(4): 416-422.
Abstract:
The phase and frequency locking of microwave, millimeter wave power combining were analysed and summarized in an all-round way. The master/slave phase locking of cavity oscillators, the peer phase locking of mutually coupled oscillators, and the peer phase locking of ring-connected multiple oscillators were investigated. The results of numerical calculations, the relations of phase to phase locking, and the model and osillator parameters were given. And the cavity and space power combining aspects for microwave and millineter wave were presented.
The phase and frequency locking of microwave, millimeter wave power combining were analysed and summarized in an all-round way. The master/slave phase locking of cavity oscillators, the peer phase locking of mutually coupled oscillators, and the peer phase locking of ring-connected multiple oscillators were investigated. The results of numerical calculations, the relations of phase to phase locking, and the model and osillator parameters were given. And the cavity and space power combining aspects for microwave and millineter wave were presented.
1994, 16(4): 423-427.
Abstract:
A program which can calculate resonant frequencies with arbitrary modes by FD-TD method coupled with the discrete Fourier transform is set up. Several resonators including coaxial resonators, empty cylindrical resonators, dielectric loaded cylindrical resonator and dielectric resonator are studied by this method, especially the spurious mode s resonant frequencies of the coaxial cavity are obtained. The numerical results are in excellent agreement with the rigorous theoretical solutions and experimental results. The resonant frequencies of a kind of two-layer dielectric-loaded cavity are also studied and some useful results are obtained.
A program which can calculate resonant frequencies with arbitrary modes by FD-TD method coupled with the discrete Fourier transform is set up. Several resonators including coaxial resonators, empty cylindrical resonators, dielectric loaded cylindrical resonator and dielectric resonator are studied by this method, especially the spurious mode s resonant frequencies of the coaxial cavity are obtained. The numerical results are in excellent agreement with the rigorous theoretical solutions and experimental results. The resonant frequencies of a kind of two-layer dielectric-loaded cavity are also studied and some useful results are obtained.
1994, 16(4): 428-431.
Abstract:
The complex ray expansion is a simple approach for target scattering field computation, whose effectiveness depends on the systematic investigation of its error. In this paper, plane wave spectral integral is used as a standard reference and the distance defined by norm in L2 space is introduced as the error function for comparison between the two methods, and then the error characteristics of complex ray expansion appoach for target scattering field computation are obtained. The way to decrease the error and the application range of the complex ray expansion method are also obtained.
The complex ray expansion is a simple approach for target scattering field computation, whose effectiveness depends on the systematic investigation of its error. In this paper, plane wave spectral integral is used as a standard reference and the distance defined by norm in L2 space is introduced as the error function for comparison between the two methods, and then the error characteristics of complex ray expansion appoach for target scattering field computation are obtained. The way to decrease the error and the application range of the complex ray expansion method are also obtained.
1994, 16(4): 432-438.
Abstract:
The formulas of dyadic Greens function for two-layer chiral electric dipole antenna are derived at first, and using the method of saddle-point integration,the expression of radiation field of electric dipole antenna is also derived. The ef fects of chirality admittance on the radiation pattern, maximum fields in the direction ＝0and resonance frequencies are examined. The results show that chiral media have potential applications in antenna areas.
The formulas of dyadic Greens function for two-layer chiral electric dipole antenna are derived at first, and using the method of saddle-point integration,the expression of radiation field of electric dipole antenna is also derived. The ef fects of chirality admittance on the radiation pattern, maximum fields in the direction ＝0and resonance frequencies are examined. The results show that chiral media have potential applications in antenna areas.
1994, 16(4): 439-443.
Abstract:
This paper presents a general theory of chiroplasma waveguides, which consist of cylindrical waveguides filled with chiroplasma materials. The relations between the transverse components and the longitudinal parts of electromagnetic fields in the waveguides are derived, and formulas for calculating the longitudinal field components are also given. As an illustrative example, the parallel-plate chiroplasma waveguide is considered in detail. The dispersion diagrams of the parallel-plate chiroplasma waveguide are presented.
This paper presents a general theory of chiroplasma waveguides, which consist of cylindrical waveguides filled with chiroplasma materials. The relations between the transverse components and the longitudinal parts of electromagnetic fields in the waveguides are derived, and formulas for calculating the longitudinal field components are also given. As an illustrative example, the parallel-plate chiroplasma waveguide is considered in detail. The dispersion diagrams of the parallel-plate chiroplasma waveguide are presented.
1994, 16(4): 444-448.
Abstract:
A novel super-PC based SAR imaging processor is presented and its system configuration and software design are analyzed in detail. Finally the advantages of this processor are sufficiently proved by the experimental results.
A novel super-PC based SAR imaging processor is presented and its system configuration and software design are analyzed in detail. Finally the advantages of this processor are sufficiently proved by the experimental results.
