ISSN 
2002 Vol. 31, No. 6
2002, 31(6): 551-556.
Abstract:
In this paper, a blind channel estimator based on the aid of Pseudo-Pilot-Symbols(PPS) has been proposed relying on the character of OFDM system. Unlike pilots which are used for estimation of channel and must waste some useful bandwidth, the PPSs, whose power can be boosted 3 dB or 6 dB to suppress efficiently the additive noise, are useful data transmitted, thus efficiency of the OFDM system has been increased. Performance simulation of the proposed estimator including Mean Squares Error (MSE) of channel and uncoded Bit Error Rate(BER) have been taken, and the results show the estimator is efficient.
In this paper, a blind channel estimator based on the aid of Pseudo-Pilot-Symbols(PPS) has been proposed relying on the character of OFDM system. Unlike pilots which are used for estimation of channel and must waste some useful bandwidth, the PPSs, whose power can be boosted 3 dB or 6 dB to suppress efficiently the additive noise, are useful data transmitted, thus efficiency of the OFDM system has been increased. Performance simulation of the proposed estimator including Mean Squares Error (MSE) of channel and uncoded Bit Error Rate(BER) have been taken, and the results show the estimator is efficient.
2002, 31(6): 557-561.
Abstract:
An expression of impulse response was deduced and a kind of optimum design method for digital prefilter is proposed in this paper. Design a kind of optimum digital prefilter. Simulate a timing recovery loop in order to get statistical data about timing jitter. Discuss the convergence characteristic of timing recovery loop. Compare the relation between timing jitter and signal to noise ratio, the relation between timing jitter and noise bandwidth of loop, the relation between symbol error ratio and signal to noise ratio in optimum prefilter and no prefilter. The result of simulation proved this design method has great affection to reduced timing jitter.
An expression of impulse response was deduced and a kind of optimum design method for digital prefilter is proposed in this paper. Design a kind of optimum digital prefilter. Simulate a timing recovery loop in order to get statistical data about timing jitter. Discuss the convergence characteristic of timing recovery loop. Compare the relation between timing jitter and signal to noise ratio, the relation between timing jitter and noise bandwidth of loop, the relation between symbol error ratio and signal to noise ratio in optimum prefilter and no prefilter. The result of simulation proved this design method has great affection to reduced timing jitter.
2002, 31(6): 562-565.
Abstract:
Since it is crucial to design the oscillator in the signal processing modules for generating the robust detection signal for the passive proximity detection system and the system detects targets through generating quasi-electrostatic field, this paper analyzes the detection signal of a passive proximity detection system based on capacitance theory is analyzed. Further, the generation mechanism of detection signal is described by the analysis of electromagnetic feature for three conductors. The simulation experiments indicate the core of related module, and describe the characteristic of the output of frequency discriminator under different intersection angles.
Since it is crucial to design the oscillator in the signal processing modules for generating the robust detection signal for the passive proximity detection system and the system detects targets through generating quasi-electrostatic field, this paper analyzes the detection signal of a passive proximity detection system based on capacitance theory is analyzed. Further, the generation mechanism of detection signal is described by the analysis of electromagnetic feature for three conductors. The simulation experiments indicate the core of related module, and describe the characteristic of the output of frequency discriminator under different intersection angles.
2002, 31(6): 566-570.
Abstract:
This paper presents a good double gained logarithmic IF amplifier. It can be used for the radar receiver that displays the moving target. The circuit property and the adjusting method are discussed in this paper. It also provides the unit circuit diagram and the total output characteristic with Electronics Workbench 5.0c.It gives some targets for function of circuit and points out some problems.
This paper presents a good double gained logarithmic IF amplifier. It can be used for the radar receiver that displays the moving target. The circuit property and the adjusting method are discussed in this paper. It also provides the unit circuit diagram and the total output characteristic with Electronics Workbench 5.0c.It gives some targets for function of circuit and points out some problems.
2002, 31(6): 571-575.
Abstract:
In present paper, the homogeneous dispersion nano powder of BaO-Nd2O3-TiO2 was prepared by citrate method. The average size of particle is about 30nm by X-ray diffraction and Transmission Electron Microscope. Its main phase is Nd2Ti2O7, and there is a little second phase of BaNd2Ti4O12 after 1300℃ sintering. The single layer microwave ceramic capacitor prepared by this ceramic material which has excellent microwave dielectric properties.
In present paper, the homogeneous dispersion nano powder of BaO-Nd2O3-TiO2 was prepared by citrate method. The average size of particle is about 30nm by X-ray diffraction and Transmission Electron Microscope. Its main phase is Nd2Ti2O7, and there is a little second phase of BaNd2Ti4O12 after 1300℃ sintering. The single layer microwave ceramic capacitor prepared by this ceramic material which has excellent microwave dielectric properties.
2002, 31(6): 576-581.
Abstract:
It is described in this paper for the heating control study on JN60' coke oven and application, the scheme of cascade control for flue temperature and feedforward control for draft used in the system, the strategy of fuzzy inference, establish of the mathematical model for heating control and technology, utilizes the coking index as the parameter on line to control coke quality. The results indicates that average energy conservation is about 3.5%, the temperature fluctuation is below 3℃,the steady coefficient of temperature is above 0.95.
It is described in this paper for the heating control study on JN60' coke oven and application, the scheme of cascade control for flue temperature and feedforward control for draft used in the system, the strategy of fuzzy inference, establish of the mathematical model for heating control and technology, utilizes the coking index as the parameter on line to control coke quality. The results indicates that average energy conservation is about 3.5%, the temperature fluctuation is below 3℃,the steady coefficient of temperature is above 0.95.
2002, 31(6): 582-584.
Abstract:
According to the theory of finite element,the finite element model of the bracket,a key supporting part in a product subjected to dynamic load, is established for modal analysis and the first six order modal parameter,including natural frequencies and viberation modes, is caculated.By comparing the caculated result with the experimental result,the caculated result is proved to be reasonable.Finally, some structure modifications are made to improve the dynamic behaviour of the bracket.
According to the theory of finite element,the finite element model of the bracket,a key supporting part in a product subjected to dynamic load, is established for modal analysis and the first six order modal parameter,including natural frequencies and viberation modes, is caculated.By comparing the caculated result with the experimental result,the caculated result is proved to be reasonable.Finally, some structure modifications are made to improve the dynamic behaviour of the bracket.
2002, 31(6): 585-589.
Abstract:
Current trends of electronic technologies suggest that embedded systems will be implemented on monolithic silicon chips. These constraints are forcing fundamental changes in the way we design software and hardware in SOCs. This article describes a novel top-down ASIC system design methodology and related technologies. Finally, we present our experience with using top-down approaches to design the digital base band chip of GPRS mobile phone.
Current trends of electronic technologies suggest that embedded systems will be implemented on monolithic silicon chips. These constraints are forcing fundamental changes in the way we design software and hardware in SOCs. This article describes a novel top-down ASIC system design methodology and related technologies. Finally, we present our experience with using top-down approaches to design the digital base band chip of GPRS mobile phone.
2002, 31(6): 590-594.
Abstract:
There is no uniform standard to describe the metadata of photograph presently, and it is usually diffcult to get all the characters of photograph when building a Photograph Data Base(PDB). Therefore, higher extensibility is required for PDB system. In respect of the extensibility of PDB, this paper analyzes the shortcomings of traditional RDBMS and introduces a new solution based on Native XML-Database which uses XML format to describe and store the metadata of photographs. Making use of the extensibility and structural storage of XML, this solution effectively implements the extensibility of the PDB and enables high retrieval capability and cross-platform character of it.
There is no uniform standard to describe the metadata of photograph presently, and it is usually diffcult to get all the characters of photograph when building a Photograph Data Base(PDB). Therefore, higher extensibility is required for PDB system. In respect of the extensibility of PDB, this paper analyzes the shortcomings of traditional RDBMS and introduces a new solution based on Native XML-Database which uses XML format to describe and store the metadata of photographs. Making use of the extensibility and structural storage of XML, this solution effectively implements the extensibility of the PDB and enables high retrieval capability and cross-platform character of it.
2002, 31(6): 595-601.
Abstract:
Based on the analysis of distributed information, the design and structure of a distributed information system platform based on mobile Agent technology is proposed. In this platform, multiple mobile agents with belief, desire and intention collaborate to perform the task of managing and retrieving information in a distributed environment. Development of information system on it can be very convenient. Also, a sample system is provided to illustrate the application of this platform.
Based on the analysis of distributed information, the design and structure of a distributed information system platform based on mobile Agent technology is proposed. In this platform, multiple mobile agents with belief, desire and intention collaborate to perform the task of managing and retrieving information in a distributed environment. Development of information system on it can be very convenient. Also, a sample system is provided to illustrate the application of this platform.
2002, 31(6): 602-607.
Abstract:
Layered transmission of data is the general recommended solution to the problem of varying bandwidth constraints in multicast applications. In this paper, several existing layered multicast congestion control protocols are analyzed and their inherent shortcomings are pointed out. Then a novel layered multicast congestion control, PLMCC that is based on packet-pair, is presented. In PLMCC, middle nodes and receivers infer local available bandwidth accurately and quickly by hop-by-hop downward packet-pair. Moreover, each receiver can obtain its optimal throughput in the least time just only sending feedback message to its parent. Simulation results show that PLMCC not only can converge fast, but also is TCP-friendly and scalable.
Layered transmission of data is the general recommended solution to the problem of varying bandwidth constraints in multicast applications. In this paper, several existing layered multicast congestion control protocols are analyzed and their inherent shortcomings are pointed out. Then a novel layered multicast congestion control, PLMCC that is based on packet-pair, is presented. In PLMCC, middle nodes and receivers infer local available bandwidth accurately and quickly by hop-by-hop downward packet-pair. Moreover, each receiver can obtain its optimal throughput in the least time just only sending feedback message to its parent. Simulation results show that PLMCC not only can converge fast, but also is TCP-friendly and scalable.
2002, 31(6): 608-611.
Abstract:
This paper aims at achieving higher fault coverage for circuits under test with less hardware overhead and time consumption. One Configuration approach of multiple scan chain is presented based on the shift-and-add property of m sequence generated by Linear Feedback Shift Register (LFSR) with maxium sequence length, it enables LFSR with shorter size to drive multiple scan chains. In order to alleviate correlation between the bit streams of LFSR, a fast design meathod is presented also based on logic stimulation. Experiment results prove the effectivness of this approach, it can be used both to internal test and external test of VLSI.
This paper aims at achieving higher fault coverage for circuits under test with less hardware overhead and time consumption. One Configuration approach of multiple scan chain is presented based on the shift-and-add property of m sequence generated by Linear Feedback Shift Register (LFSR) with maxium sequence length, it enables LFSR with shorter size to drive multiple scan chains. In order to alleviate correlation between the bit streams of LFSR, a fast design meathod is presented also based on logic stimulation. Experiment results prove the effectivness of this approach, it can be used both to internal test and external test of VLSI.
2002, 31(6): 612-618.
Abstract:
Based on the eigensubspace estimation using discrete recurrent neural networks, we propose algorithms to solve the problem of eigensubspace estimation for positive definite symmetric matrix. Neural networks are formulated as discrete time systems, they have advantages for computer simulations over digital simulations of continuous time neural network models. Thus they can be easily implemented in digital hardware. Simulation results are given to show the performance of networks.
Based on the eigensubspace estimation using discrete recurrent neural networks, we propose algorithms to solve the problem of eigensubspace estimation for positive definite symmetric matrix. Neural networks are formulated as discrete time systems, they have advantages for computer simulations over digital simulations of continuous time neural network models. Thus they can be easily implemented in digital hardware. Simulation results are given to show the performance of networks.
2002, 31(6): 619-623.
Abstract:
Based on the estimation of average distance derived from the theories of asymptotic optimization of VRP problems, this paper established a model to assist the programming and management of the distribution system for E-Shopping. The results can be used for management decision in aspects of economics. This model is characterized by the considerations on the probabilistic of real system and the conclusions are applied to management decisions under so much realistic consideration.
Based on the estimation of average distance derived from the theories of asymptotic optimization of VRP problems, this paper established a model to assist the programming and management of the distribution system for E-Shopping. The results can be used for management decision in aspects of economics. This model is characterized by the considerations on the probabilistic of real system and the conclusions are applied to management decisions under so much realistic consideration.
2002, 31(6): 624-629.
Abstract:
A wide area network oriented service discovery mechanism is described in this paper. Discovery servers in wide area networks are organized into a tree structure with each server node saves the address of its neighbor nodes, namely its father, brothers and children in the tree. The transmission message of service request is appended certain forwarding information. By matching the received service requests with service repository, each node response the service request or deals with the appended information in it and forward it to one of neighbor nodes. Thus, service discovery in wide area networks can be achieved effectively.
A wide area network oriented service discovery mechanism is described in this paper. Discovery servers in wide area networks are organized into a tree structure with each server node saves the address of its neighbor nodes, namely its father, brothers and children in the tree. The transmission message of service request is appended certain forwarding information. By matching the received service requests with service repository, each node response the service request or deals with the appended information in it and forward it to one of neighbor nodes. Thus, service discovery in wide area networks can be achieved effectively.
2002, 31(6): 630-635.
Abstract:
Article attempt at the concepts of CSCW, form each let user link up with at editor virtual to learn the classroom each other under the environment of network, Have put forward a piece of "on-line collaborative edit system" based on web platform. The system establishes cooperation environment CSCW(computer-Supported Cooperative Work)through Internet and forms a virtual group for collaborative leaning. It will promote experience sharing, information exchange and discussion among teachers and students. And has probed into the popularization value of this systematic model.
Article attempt at the concepts of CSCW, form each let user link up with at editor virtual to learn the classroom each other under the environment of network, Have put forward a piece of "on-line collaborative edit system" based on web platform. The system establishes cooperation environment CSCW(computer-Supported Cooperative Work)through Internet and forms a virtual group for collaborative leaning. It will promote experience sharing, information exchange and discussion among teachers and students. And has probed into the popularization value of this systematic model.
2002, 31(6): 636-641.
Abstract:
This paper analyse the model of controller registers for IDE interface hard disk drive, summarized some key technic about read-write hard disk drive and a design about clone hard disk. We can directly read-write the sector,and it has no concern with operating system and the structure of hard disk drive. Combine with C and Assemble language, We give an realy application. the method is easy and useful.
This paper analyse the model of controller registers for IDE interface hard disk drive, summarized some key technic about read-write hard disk drive and a design about clone hard disk. We can directly read-write the sector,and it has no concern with operating system and the structure of hard disk drive. Combine with C and Assemble language, We give an realy application. the method is easy and useful.
2002, 31(6): 642-647.
Abstract:
A pivoting-based algorithm for the system of linear inequalities is proposed. Since it solves the system directly without adding any variables, a compact form is used for operations. It not only requires less computation for each iteration but also makes easy the theoretical analysis for the characteristics of the solved problem. It is proved that this method terminates as long as the entering and leaving variables are selected by the smallest-subscript rule in each iteration. This proof is essentially that proposed by G.B. Bland, but varies greatly in the form. The experiment shows that this method is very efficient for solving Markowitz's portfolio selection model (convex quadratic programming).
A pivoting-based algorithm for the system of linear inequalities is proposed. Since it solves the system directly without adding any variables, a compact form is used for operations. It not only requires less computation for each iteration but also makes easy the theoretical analysis for the characteristics of the solved problem. It is proved that this method terminates as long as the entering and leaving variables are selected by the smallest-subscript rule in each iteration. This proof is essentially that proposed by G.B. Bland, but varies greatly in the form. The experiment shows that this method is very efficient for solving Markowitz's portfolio selection model (convex quadratic programming).
2002, 31(6): 648-653.
Abstract:
The precondition of this paper is that the income of enterprises' managers should be tied to their performance. Factors that influence income of Enterprises' managers include individual factors, enterprise's factor, as well as environmental factors are described in this paper. According to their interaction with each other, these factors are qualitatively processed by using ISM method, and a multilevel stratum structure model for influential factors of managers' income is established. Through analyzing the model, we come to the conclusion that among these factors, enterprise's factor (enterprises' distribution structure) is key to managers' income. This will have great theoretic and realistic significance on the design of effective managers' incentive system.
The precondition of this paper is that the income of enterprises' managers should be tied to their performance. Factors that influence income of Enterprises' managers include individual factors, enterprise's factor, as well as environmental factors are described in this paper. According to their interaction with each other, these factors are qualitatively processed by using ISM method, and a multilevel stratum structure model for influential factors of managers' income is established. Through analyzing the model, we come to the conclusion that among these factors, enterprise's factor (enterprises' distribution structure) is key to managers' income. This will have great theoretic and realistic significance on the design of effective managers' incentive system.
