Showing papers by "Beijing University of Posts and Telecommunications published in 1988"
TL;DR: In this article, a counterexample to the theorem in the paper by N.A. Tsolas et al. is presented, showing the potential existence of additional structures within the boundary.
Abstract: Recent results on the composition of the stability boundary by N.A. Tsolas et al. (IEEE Trans. Circuits Syst., vol.CAS-32, no.10, pp.1041-9, Oct. 1985) and J. Zaborszky et al. (Proc. IFAC Symp. Power Syst. Power Plant. Contr., Beijing, China, Aug. 1986, pp.597-603) claimed that it consisted of the stable manifolds of index-one unstable equilibria and their closures. A counterexample shows the potential existence of additional structures within the boundary. This finding invalidates numerous theorems published in the literature. The author concedes that the counterexample to the theorem in the paper by N.A. Tsolas et al. is unassailable and identifies the error in his proof. >
21 citations
TL;DR: In this article, an improved coupledmode theory for the propagation of modulated light waves in anisotropic dielectric waveguides is presented, which is applicable to both bulk and waveguide modulators/switches from DC to the high-frequency band.
Abstract: An improved coupled-mode theory for the propagation of modulated light waves in anisotropic dielectric waveguides is presented. Starting from Maxwell's equations, a partial differential equation is derived to describe mode-coupling between two normal modes which may propagate in anisotropic waveguide systems under modulation. The theory is applied to the analysis of typical waveguide modulators; examples for LiNbO/sub 3/ phase modulator, Mach-Zehnder, and directional coupler modulator are presented. The theory is applicable to both bulk and waveguide modulators/switches from DC to the high-frequency band. The only limitation is that the modulating wave has to propagate collinearly to the light waves. >
16 citations
TL;DR: By using the generator matrices or the parity check matrices of MDS codes, this work can implement a new class of threshold systems in cryptography.
Abstract: The deep relationship between MDS codes and threshold schemes in cryptography is initially reported in this paper. We have found that by using the generator matrices or the parity check matrices of MDS codes, we can implement a new class of threshold systems in cryptography.
8 citations
TL;DR: In this paper, the authors derived a formula of linewidth for a semiconductor-optical-fiber ring laser by using coupled rate equations for the active and passive cavity.
Abstract: The authors derive a formula of linewidth for a semiconductor-optical-fiber ring laser by using coupled rate equations for the active and passive cavity. It is shown that the linewidth is not only the function of the two-cavity length ratio and time delay in fiber, but also the function of light intensity ratio of the two cavities and the phase shift introduced by junctions between the gain medium and the optical fiber. >
7 citations
07 Jun 1988
TL;DR: In this article, an approach to analog fault diagnosis for resistive circuits is presented, where the diagnosis equations derived on the basis of nodalvoltage measurement are quadratic.
Abstract: An approach to analog fault diagnosis for resistive circuits is presented. The diagnosis equations derived on the basis of nodal-voltage measurement are quadratic. Using the concept of DC equivalent resistance, the authors propose an efficient approach to the diagnosis of nonlinear resistive circuits. Based on this approach, they have implemented an experimental analog automatic diagnostic system, which can diagnose any fault elements in practical linear resistive circuits. >
6 citations
TL;DR: In this paper, a new structure of optical homodyne receiver based on a 4×4 fiber directional coupler is proposed, which has the characteristics of balanced detection, high receiving sensitivity, and the ability to tolerate wide laser linewidth.
Abstract: A new structure of optical homodyne receiver based on a 4×4 fibre directional coupler is proposed. It has the characteristics of balanced detection, high receiving sensitivity, and the ability to tolerate wide laser linewidth.
6 citations
07 Jun 1988
TL;DR: This approach uses a recently defined two-graph method which can be applied to a circuit containing nonlinear multiports, with the partition of the terminal equations into linear and nonlinear submatrices to facilitate the solution of the circuit equation.
Abstract: An analytic derivation to obtain the generalized modified nodal circuit equation which is suitable for nonlinear multiports with discrete data description is represented. For this purpose, a numerical data model for the nonlinear multiport is defined, which has the same form as the ordinary transfer parameters of the network. This approach uses a recently defined two-graph method which can be applied to a circuit containing nonlinear multiports, with the partition of the terminal equations into linear and nonlinear submatrices to facilitate the solution of the circuit equation. >
3 citations
TL;DR: In this paper, a new speckle carrier technique is presented, which can solve the problem that the direction of the displacement vector is ambiguously determined when the point-wise method is used.
Abstract: A new speckle carrier technique is presented, which can solve the problem in one-beam laser speckle interferometry, that the direction of the displacement vector is ambiguously determined when the point-wise method is used. The method is very easy and convenient and the results are good. Some discussion about the relationship between the carrier frequency and the displacements is given.
3 citations
07 Jun 1988
TL;DR: The proposed combined time-delay adaptive filter combines some advantages possessed by common types of the FIR (finite-impulse response) adaptive filter, including its simple configuration, its covering a long period of signal response, as well as a fast convergence speed.
Abstract: The proposed combined time-delay adaptive filter combines some advantages possessed by common types of the FIR (finite-impulse response) adaptive filter. These advantages include its simple configuration, its covering a long period of signal response, as well as a fast convergence speed. In addition, this adaptive filter is more suitable for the baseband full-duplex two-wire data transmission system, particularly in the ISDN (integrated-service digital network) U-interface subscriber loop, as an echo canceller. In implementation, the architecture is mainly based on a digital signal processor chip. >
3 citations
TL;DR: In this paper, it was shown that the Hardy and Streifer (HS) formulation is correct only under the weakly coupling condition and defined the weak coupling condition quantitatively, thus the debate may be closed.
Abstract: The coupled mode formulation of Hardy and Streifer (HS) is currently under discussion. To settle this argument I derive the HS formulation by the equivalent current theory of optical waveguide coupling, and hence show that the HS formulation is based upon the same principles of the common coupling equation and is correct only under the weakly coupling condition. By making this clear and defining the weakly coupling condition quantitatively, the debate may be closed.
2 citations
07 Jun 1988
TL;DR: In this paper, a method for designing non-reciprocal 2D filters is proposed based on the use of non-rewarded one-way lines and 1-D reciprocal subnetworks.
Abstract: A method for designing nonreciprocal 2-D filters is proposed. The approach is based on the use of nonreciprocal one-way lines and 1-D reciprocal subnetworks. The problem of the approximation and realization of 2-D filters can then be solved in terms of the 1-D filter theory. Two examples are considered: a mixed lumped-distributed network and a wave-digital filter. >
TL;DR: In this article, the Brillouin equations with strong nonlinearity are solved using a perturbation technique, and the calculated results agree quite well with the published experimental results.
Abstract: The Brillouin equations with strong nonlinearity are solved using a perturbation technique. The calculated results agree quite well with the published experimental results [1, 2]. In addition some new conclusions are obtained from our analysis.
TL;DR: Decision-driven PLL is analyzed for optic fiber BPSK homodyne detection systems and the effects of laser linewidth and detector shot noise are considered.
Abstract: Decision-driven PLL is analyzed for optic fiber BPSK homodyne detection systems. The effects of laser linewidth and detector shot noise are considered. The optimization and selection of the loop parameters are discussed.
TL;DR: A method, based on the equivalent-current theory of optical waveguide coupling, by which metal-clad optical fiber polarizers can be analyzed and good agreement between theoretical predictions and previously published experimental results is attained.
Abstract: We present a method, based on the equivalent-current theory of optical waveguide coupling, by which metal-clad optical fiber polarizers can be analyzed. Good agreement between theoretical predictions and previously published experimental results is attained.
28 Nov 1988
TL;DR: A flow control algorithm for virtual circuits is proposed which takes into account the fact that in a packet switched network, different users can have different requirements for throughput and average delay.
Abstract: A flow control algorithm for virtual circuits is proposed which takes into account the fact that in a packet switched network, different users can have different requirements for throughput and average delay. The algorithm is based on a new definition of power based on multiple objective optimization theory. Problems of approximation and convergence are discussed, and a numerical example is given. >
07 Jun 1988
TL;DR: In this article, a simplified version of the block least mean square (LMS) algorithm is proposed, which has a relatively simple configuration and is more flexible in the selection of block length.
Abstract: A simplified version of the block least mean square (LMS) algorithm is proposed. Compared with the conventional block algorithms, the proposed algorithm possesses the following features: (1) it has a relatively simple configuration and is more flexible in the selection of the block length L: (2) it gives a much larger complexity ratio than that given by the conventional block algorithms: (3) it has a convergence behavior not inferior to its counterpart given by G.A. Clack et al. (1981); and (4) it has potential for use in real-time processing environment. >
TL;DR: In this article, a new model for diffusion from periodical Ti strips into LiNbO3 crystal using the depth-dependent diffusion coefficient is presented, which is based on the depth dependent diffusion coefficient.
Abstract: In this paper, we present a new model for diffusion from periodical Ti strips into LiNbO3 crystal using the depth-dependent diffusion coefficient.
TL;DR: This paper presents four classes of codes which meet the Johnson's upper bound and two classes of code which have gone beyond the Graham's lower bound.
Abstract: This paper presents four classes of codes which meet the Johnson's upper bound and two classes of codes which have gone beyond the Graham's lower bound.
11 Apr 1988
TL;DR: The proposed architecture not only has a faster convergence speed than that of usual table lookup adaptive filters, but can also compensate the long period of echo tail caused by insufficient filter taps, especially when it is used in the full-duplex two-wire data transmission system with a net rate of 144 kb/s.
Abstract: A good adaptive echo canceller (EC), in terms of its performance, is an interesting problem for those who are engaged in the ISDN (integrated-services digital network) U-interface subscriber loop design. It is also important to implement an EC with low cost chips. An adaptive EC is proposed that makes its contribution in this respect. The filter combines some advantages possessed by common types of FIR (finite-impulse response) adaptive filters, transversal, and table lookup filters, together. In implementation, the filter design is mainly based on developing DSP (digital-signal-processor) chips, e.g. the Texas Instruments TMS320 family of microprocessors. The proposed architecture not only has a faster convergence speed than that of usual table lookup adaptive filters, but can also compensate the long period of echo tail caused by insufficient filter taps, especially when it is used in the full-duplex two-wire data transmission system with a net rate of 144 kb/s. >