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1993 Vol. 15, No. 6
Display Method:
1993, 15(6): 561-566.
Abstract:
A fast algorithm of azimuth processing for spaceborne SAR, which is called SPECAN algorithm, is proposed. Comparing with general frequency algorithms, SPECAN has advantages in computation, memory and structure. SPECAN algorithm is very important for surveying real-time processing of spacehorne SAR. The structure and special problems for SPECAN algorithm used in spaceborne SAR are mainly engaged in this paper. Finally, raw data of SEASAT-A satellite is used to test the feasibility of SPECAN algorithm.
A fast algorithm of azimuth processing for spaceborne SAR, which is called SPECAN algorithm, is proposed. Comparing with general frequency algorithms, SPECAN has advantages in computation, memory and structure. SPECAN algorithm is very important for surveying real-time processing of spacehorne SAR. The structure and special problems for SPECAN algorithm used in spaceborne SAR are mainly engaged in this paper. Finally, raw data of SEASAT-A satellite is used to test the feasibility of SPECAN algorithm.
1993, 15(6): 567-574.
Abstract:
The formulation of Doppler parameters (Doppler centroid and Doppler frequency rate) from the geometry of satellite-borne SAR is derived. After analysing the error sensitivity of SAR orbit and attitude parameters, the error allocation principle for satellite attitude parameters is presented. Finally, the feasibility to calculate the satellite attitude from the Doppler centroid extracted from SAR raw data is proved.
The formulation of Doppler parameters (Doppler centroid and Doppler frequency rate) from the geometry of satellite-borne SAR is derived. After analysing the error sensitivity of SAR orbit and attitude parameters, the error allocation principle for satellite attitude parameters is presented. Finally, the feasibility to calculate the satellite attitude from the Doppler centroid extracted from SAR raw data is proved.
1993, 15(6): 575-580.
Abstract:
Analyzing the difference between the joint-domain and the cascade proccessing for phase array radar, this paper propose a new partial adaptive spatial-temporal joint domain processor with highly tolerant ability in the presence of random amplitude and phase errors existing in rhe array elements. Partial joint adaptive processing is implemented in the angle-Doppler domain transformed from the two dimensional spatial-temporal data.
Analyzing the difference between the joint-domain and the cascade proccessing for phase array radar, this paper propose a new partial adaptive spatial-temporal joint domain processor with highly tolerant ability in the presence of random amplitude and phase errors existing in rhe array elements. Partial joint adaptive processing is implemented in the angle-Doppler domain transformed from the two dimensional spatial-temporal data.
1993, 15(6): 581-587.
Abstract:
The issue of range sidelobe suppression filters for biphase coded signals is investigated. By analysing the characteristic in frequency domam, a design method for minimized peak sidelobe filters, which is suited for various code length is suggested. The computer simulation of sidelobe suppression is made based on 190-bit biphase coded signals. This paper presents a method to improve the Doppler-tolerance by combining the frequency diversity and non-coherent sidelobe reduction filters. The simulation results show that the peak sidelobe reduction filters meet the requirements of modern radar systems.
The issue of range sidelobe suppression filters for biphase coded signals is investigated. By analysing the characteristic in frequency domam, a design method for minimized peak sidelobe filters, which is suited for various code length is suggested. The computer simulation of sidelobe suppression is made based on 190-bit biphase coded signals. This paper presents a method to improve the Doppler-tolerance by combining the frequency diversity and non-coherent sidelobe reduction filters. The simulation results show that the peak sidelobe reduction filters meet the requirements of modern radar systems.
1993, 15(6): 588-595.
Abstract:
A novel criterion of blind equalization is introduced for communication channels. The criterion or cost-function with respect to the complex tap-weight vector of the equalizer and to the error probability is strictly a convex function. By using gradient algorithm, the global convergence of the cost-function can be guaranteed. Analysis and simulation results demonstrate that the proposed criterion performs very well on both the computational complexity and the convergence rate.
A novel criterion of blind equalization is introduced for communication channels. The criterion or cost-function with respect to the complex tap-weight vector of the equalizer and to the error probability is strictly a convex function. By using gradient algorithm, the global convergence of the cost-function can be guaranteed. Analysis and simulation results demonstrate that the proposed criterion performs very well on both the computational complexity and the convergence rate.
1993, 15(6): 596-603.
Abstract:
It is proposed firstly that the original phase and time-delay are the main factors which affect the measuring resolution of the multitone complex envelope method. The effects of these factors are analysed and checked by the computer simulation. Finally, three possible ways to eliminate these effects are given.
It is proposed firstly that the original phase and time-delay are the main factors which affect the measuring resolution of the multitone complex envelope method. The effects of these factors are analysed and checked by the computer simulation. Finally, three possible ways to eliminate these effects are given.
1993, 15(6): 604-610.
Abstract:
Proceeding from the specific characteristics of PAL television signals adopted in China, this paper points out that if the fs=2fsc of sub-Nyquist sampling and DPCM-encoding is used for PAL complete signal, and if the blanking time is utilized to transmit code of effective area, it is possible to transmit a color TV signal over PCM three-group channel.
Proceeding from the specific characteristics of PAL television signals adopted in China, this paper points out that if the fs=2fsc of sub-Nyquist sampling and DPCM-encoding is used for PAL complete signal, and if the blanking time is utilized to transmit code of effective area, it is possible to transmit a color TV signal over PCM three-group channel.
1993, 15(6): 611-617.
Abstract:
The problem of fault diagnosis of a tree-type power network with a short-circuit or an open-circuit and a conrac resistance of arbitrary value between lines is studied. Based on nullor substitution, the method presented here is suitable for fault locating and contact resistance evaluating. Principles of diagnosis are discussed, diagcosis equations are established, and diagnosis algorithms are presented. Finally, examples for diagnosing a five-branches tree-type power network with a shore-circuit or an open-circuit art given.
The problem of fault diagnosis of a tree-type power network with a short-circuit or an open-circuit and a conrac resistance of arbitrary value between lines is studied. Based on nullor substitution, the method presented here is suitable for fault locating and contact resistance evaluating. Principles of diagnosis are discussed, diagcosis equations are established, and diagnosis algorithms are presented. Finally, examples for diagnosing a five-branches tree-type power network with a shore-circuit or an open-circuit art given.
1993, 15(6): 618-624.
Abstract:
The conducting strip interdigital capacitance on a dielectric substrate is analyzed with the moment method. The theoretical formulas are given. A number of illustrative examples are numerically calculated, which shew the correctness and the effectiveness of the method presented here.
The conducting strip interdigital capacitance on a dielectric substrate is analyzed with the moment method. The theoretical formulas are given. A number of illustrative examples are numerically calculated, which shew the correctness and the effectiveness of the method presented here.
1993, 15(6): 625-630.
Abstract:
The electromagnetic field integral equation in the quasi-optical cavity is obtained using the dyadic Green s function. An expression is derived for the input impedance of a single microstrip patch cavity excited by a coaxial probe using method of moment. The input impedance of a rectangular microstrip patch is discussed by this method. The result of this paper is similar to that of the microstrip antenna. There is very important value for designing microstrip quasi-optical oscillator.
The electromagnetic field integral equation in the quasi-optical cavity is obtained using the dyadic Green s function. An expression is derived for the input impedance of a single microstrip patch cavity excited by a coaxial probe using method of moment. The input impedance of a rectangular microstrip patch is discussed by this method. The result of this paper is similar to that of the microstrip antenna. There is very important value for designing microstrip quasi-optical oscillator.
1993, 15(6): 643-646.
Abstract:
It is proved that in the algebraic normal form of the strict majority logic function with order n= 2m+1(m1), all the nonlinear terms of k-th order, (n+1)/2kn-1, must appear. Threrfore, from the view of cryptology, such strict majority logic function has good characteristics.
It is proved that in the algebraic normal form of the strict majority logic function with order n= 2m+1(m1), all the nonlinear terms of k-th order, (n+1)/2kn-1, must appear. Threrfore, from the view of cryptology, such strict majority logic function has good characteristics.
1993, 15(6): 647-650.
Abstract:
In this paper, one-bit ternary full-adder and full-multiplier are designed by using ternary universal-logic-gate-Uhs based upon modular algebra
In this paper, one-bit ternary full-adder and full-multiplier are designed by using ternary universal-logic-gate-Uhs based upon modular algebra
1993, 15(6): 651-654.
Abstract:
A simple scheme of a profile inversion from the reflection coefficients is obtained for a half-space weakly lossy medium. Two approximations for reconstructing the permittivity and conductivity profiles are developed, both of which have closed-forms.
A simple scheme of a profile inversion from the reflection coefficients is obtained for a half-space weakly lossy medium. Two approximations for reconstructing the permittivity and conductivity profiles are developed, both of which have closed-forms.
1993, 15(6): 655-658.
Abstract:
Based on the theoretical analysis, the formula of MCP noise taecror is suggested. The results of numerical calculation show that the MCP noise can be reduced by increasing the yield of secondary electrons at MCP entrance. Accroding to this results, the possibility of reducing the noise factor by depositing certain alka lihalide compounds at the entrance of the MCP channels is discussed.
Based on the theoretical analysis, the formula of MCP noise taecror is suggested. The results of numerical calculation show that the MCP noise can be reduced by increasing the yield of secondary electrons at MCP entrance. Accroding to this results, the possibility of reducing the noise factor by depositing certain alka lihalide compounds at the entrance of the MCP channels is discussed.
THE MECHANISM FOR THE EFFECT OF OXYGEN PARTIAL PRESSURE ON THE RESPONSE OF GAS SENSORS BASED ON SnO2
1993, 15(6): 659-662.
Abstract:
A new model for gas sensors based on SnO2 is developed. The surface potential height of the SnO2 grains is controlled by: (1) Oxygen adsorption (as electron acceptor) and desorption, (2) reducing gas adsorption (as electron donor) and desorption, (3) oxidation-reduction reaction in the surface phase. The effect of oxygen partial pressure on the response of gas gensors, observed by G. Coles et al., (1991) can be well explained.
A new model for gas sensors based on SnO2 is developed. The surface potential height of the SnO2 grains is controlled by: (1) Oxygen adsorption (as electron acceptor) and desorption, (2) reducing gas adsorption (as electron donor) and desorption, (3) oxidation-reduction reaction in the surface phase. The effect of oxygen partial pressure on the response of gas gensors, observed by G. Coles et al., (1991) can be well explained.
1993, 15(6): 663-665.
Abstract:
A four pole microstrip parallel-coupled bandpass filter have been fabir-cated using epitaxial GaBaCuO thin film on LaAlO3 substrate. At 77k, the passband insertion loss is 0.45dB, the bandwidth is 500MHz. And it is suggested that several problems should be considered tor designing a high performance superconducting microstrip line filter.
A four pole microstrip parallel-coupled bandpass filter have been fabir-cated using epitaxial GaBaCuO thin film on LaAlO3 substrate. At 77k, the passband insertion loss is 0.45dB, the bandwidth is 500MHz. And it is suggested that several problems should be considered tor designing a high performance superconducting microstrip line filter.
1993, 15(6): 631-642.
Abstract:
The state-of-the-art technologies of bipolar transistors for integrated circuit, in which bipolar transistors based on bulk silicon, silicon-on insulator and SiGe stained layer are included, are discussed.
The state-of-the-art technologies of bipolar transistors for integrated circuit, in which bipolar transistors based on bulk silicon, silicon-on insulator and SiGe stained layer are included, are discussed.
