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1995 Vol. 17, No. 2
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1995, 17(2): 113-118.
Abstract:
The foundamental reflection and transmission of a plane wave from multilayered nonlinear slabs are studied by using the Volterra functional series theory. The first order approximations of reflectivity and transmissivity are derived. The numerical calculations are made to a nonlinear plate and a periodic multilayered slab, which is consisted of two different nonlinear slabs. The influences of nonlinear medium to the EM propagation are discussed.
The foundamental reflection and transmission of a plane wave from multilayered nonlinear slabs are studied by using the Volterra functional series theory. The first order approximations of reflectivity and transmissivity are derived. The numerical calculations are made to a nonlinear plate and a periodic multilayered slab, which is consisted of two different nonlinear slabs. The influences of nonlinear medium to the EM propagation are discussed.
1995, 17(2): 119-124.
Abstract:
A low sidelobe aperture designing method of multi-step amplitude quantization with pedestal is proposed, and general analysis and formulas are described. The computation results compared with author s(1993) previous method Multi-Step Amplitude Quantization (MSAQ) on peak sidelobe level, aperture efficiency, normalized input power and sidelobe degradation with tolerance are given. It is shown that, in the same conditions, the method presented in this paper is better than the MSAQ.
A low sidelobe aperture designing method of multi-step amplitude quantization with pedestal is proposed, and general analysis and formulas are described. The computation results compared with author s(1993) previous method Multi-Step Amplitude Quantization (MSAQ) on peak sidelobe level, aperture efficiency, normalized input power and sidelobe degradation with tolerance are given. It is shown that, in the same conditions, the method presented in this paper is better than the MSAQ.
1995, 17(2): 125-133.
Abstract:
Powerful HF waves modulated by ELF signals are employed to heat the lower ionosphere and generate ELF radiations that might be applicable to communication to submarines. Numerical results show that, if the frequency and effective radiation power(ERP) of the HF waves are 5MHz and 100MW respectively, with modulation frequency 100Hz, then the attenuation rates of the Quasi-TEM propagating in the earth-ionosphere waveguide are usually less than IdB/Mm, and the magnetic field strength 1000km away from the heating location is in the order of 10-8A/m. As for communication to submarines, for a specific ELF source and a given submarine location, there exists a most favorable frequency that maximizesthe receiving signals.
Powerful HF waves modulated by ELF signals are employed to heat the lower ionosphere and generate ELF radiations that might be applicable to communication to submarines. Numerical results show that, if the frequency and effective radiation power(ERP) of the HF waves are 5MHz and 100MW respectively, with modulation frequency 100Hz, then the attenuation rates of the Quasi-TEM propagating in the earth-ionosphere waveguide are usually less than IdB/Mm, and the magnetic field strength 1000km away from the heating location is in the order of 10-8A/m. As for communication to submarines, for a specific ELF source and a given submarine location, there exists a most favorable frequency that maximizesthe receiving signals.
1995, 17(2): 134-139.
Abstract:
This paper proposes a new variable-bit-rate layered coding algorithm based on zubband coding. It makes full use of the advantage of variable-bit-rate transmission of ATM networks and has the ability to compensate picture degradation caused by cell loss, thus a high quality stable video communication is realized. The coding algorithm, cell composition method and simulation results are given.
This paper proposes a new variable-bit-rate layered coding algorithm based on zubband coding. It makes full use of the advantage of variable-bit-rate transmission of ATM networks and has the ability to compensate picture degradation caused by cell loss, thus a high quality stable video communication is realized. The coding algorithm, cell composition method and simulation results are given.
1995, 17(2): 140-144.
Abstract:
Using m-sequence over the finite field GF(2m) of degree L to controll m-sequence over GF(2m) of degree L, a class of periodic sequences with large linear complexity is constructed. The lower bounds of the linear complexity of the sequences are L((L+1)m- Lm).
Using m-sequence over the finite field GF(2m) of degree L to controll m-sequence over GF(2m) of degree L, a class of periodic sequences with large linear complexity is constructed. The lower bounds of the linear complexity of the sequences are L((L+1)m- Lm).
1995, 17(2): 145-153.
Abstract:
The feature points are often extracted as matching feature. And a constraint minimum energy function can be got by using the method of disparity estimation under the condition of certain matching criterion. The results of simulated experiments show that the stereo matching can be obtained. It is possible to escape from local minimum by simulated annealing, and the energy function can reach the global minimum.
The feature points are often extracted as matching feature. And a constraint minimum energy function can be got by using the method of disparity estimation under the condition of certain matching criterion. The results of simulated experiments show that the stereo matching can be obtained. It is possible to escape from local minimum by simulated annealing, and the energy function can reach the global minimum.
1995, 17(2): 154-160.
Abstract:
The extinction ratio test of analogue ranging is adopted directly to check the sensitivity of pulsed laser range finders, then the influence of weather and the limitation of terrain in long-distance ranging can be elinminated effectively. By analyzing the test data obtained and comparing them with the range measuring ability, it shows that this check method is effective.
The extinction ratio test of analogue ranging is adopted directly to check the sensitivity of pulsed laser range finders, then the influence of weather and the limitation of terrain in long-distance ranging can be elinminated effectively. By analyzing the test data obtained and comparing them with the range measuring ability, it shows that this check method is effective.
1995, 17(2): 161-169.
Abstract:
A subnetwork is able to be solved, if its terminal currents have been determined. In this paper, the concepts of island and bridge are presented, the CCVS model of n-terminal subnetwork is constructed, the island equations are deduced and then the currents of each subnetwork terminal are obtained. Using this method, the computing time and the memory space can be saved.
A subnetwork is able to be solved, if its terminal currents have been determined. In this paper, the concepts of island and bridge are presented, the CCVS model of n-terminal subnetwork is constructed, the island equations are deduced and then the currents of each subnetwork terminal are obtained. Using this method, the computing time and the memory space can be saved.
1995, 17(2): 170-174.
Abstract:
Three-unit array was constructed with SnO2 gas sensors. Two classi-fers, the k-nearest neighbour and the weighted k-nearest neighbour, were used. It is shown that the recognition probability of the former is 40 to ethanol and 90 to gasoline and that of the latter is 70 and 90 respectively. Pattern recognition is an effective method to improve selectivity of gas sensors.
Three-unit array was constructed with SnO2 gas sensors. Two classi-fers, the k-nearest neighbour and the weighted k-nearest neighbour, were used. It is shown that the recognition probability of the former is 40 to ethanol and 90 to gasoline and that of the latter is 70 and 90 respectively. Pattern recognition is an effective method to improve selectivity of gas sensors.
1995, 17(2): 182-186.
Abstract:
By using the binary code instead of the ternary code, a increment in number of information bit is obtained. Then by adapting the one-element-operator, the number of information bit increases further to maximum.
By using the binary code instead of the ternary code, a increment in number of information bit is obtained. Then by adapting the one-element-operator, the number of information bit increases further to maximum.
1995, 17(2): 187-190.
Abstract:
This paper proposes a simplification method for realization of current-mode CMOS multivalued circuits. The key of this method is to find out a coverage on the K-map for a given multivalued function, which fits to the realization of current-mode CMOS circuits.
This paper proposes a simplification method for realization of current-mode CMOS multivalued circuits. The key of this method is to find out a coverage on the K-map for a given multivalued function, which fits to the realization of current-mode CMOS circuits.
1995, 17(2): 191-196.
Abstract:
The construction and specifications of a SAW storage correlator are described. A time domain processing mode spread spectrum system is presented. An analysis of interference rejection for this system is provided. The calculating formula for the probability of error of system is given. The caclulating results by using this formula agree with the experimental results.
The construction and specifications of a SAW storage correlator are described. A time domain processing mode spread spectrum system is presented. An analysis of interference rejection for this system is provided. The calculating formula for the probability of error of system is given. The caclulating results by using this formula agree with the experimental results.
1995, 17(2): 197-200.
Abstract:
A coaxial reflection-mode electrooptic sampling system is presented. This system has a temporal resolution less than 20 ps and a spatial resolution less than 3m. The internal microwave signals in GaAs coplanar waveguides have been probed by the system. This system will be apply to on-wafer tests of internal characters of GaAs high-speed integrated circuits.
A coaxial reflection-mode electrooptic sampling system is presented. This system has a temporal resolution less than 20 ps and a spatial resolution less than 3m. The internal microwave signals in GaAs coplanar waveguides have been probed by the system. This system will be apply to on-wafer tests of internal characters of GaAs high-speed integrated circuits.
1995, 17(2): 201-205.
Abstract:
The eignvalue equation, the attenuation constant a and the field distribution function of the surface wave(SW) in a conductor-backed lossy dielectric layer are derived. The relationship between the a and the parameters of the dielectric material is described. It was found that the magnetic-loss material showed better performance than the electric-loss material in attenuating the SW.
The eignvalue equation, the attenuation constant a and the field distribution function of the surface wave(SW) in a conductor-backed lossy dielectric layer are derived. The relationship between the a and the parameters of the dielectric material is described. It was found that the magnetic-loss material showed better performance than the electric-loss material in attenuating the SW.
1995, 17(2): 206-209.
Abstract:
The performance of the high resolution direction finding technique based on the spatial spectrum estimation is severely suffered with channel mismatching and mutual coupling between elements in arrays. In this paper, the mechanism of performance degradation due to above mentioned factors is analysed, and an effective method of compensation for channel mismatching and mutual coupling is proposed.
The performance of the high resolution direction finding technique based on the spatial spectrum estimation is severely suffered with channel mismatching and mutual coupling between elements in arrays. In this paper, the mechanism of performance degradation due to above mentioned factors is analysed, and an effective method of compensation for channel mismatching and mutual coupling is proposed.
1995, 17(2): 210-214.
Abstract:
The therapy principle and design of microwave prostate hyperthermia are described. This apparatus uses 915MHz microwave treatment for the prostate. The solid state microwave source and surface cooling system of special design only heats the prostate. The specially designed Foley duct and microwave radiator can be used for treatment by transurethral or transrectal. The temperature is measured and monitered automatically, and the measured data are recorded, displayed and printed in real-time by a microcomputer. The accuracy of thermosensor measurements is 0.1℃.
The therapy principle and design of microwave prostate hyperthermia are described. This apparatus uses 915MHz microwave treatment for the prostate. The solid state microwave source and surface cooling system of special design only heats the prostate. The specially designed Foley duct and microwave radiator can be used for treatment by transurethral or transrectal. The temperature is measured and monitered automatically, and the measured data are recorded, displayed and printed in real-time by a microcomputer. The accuracy of thermosensor measurements is 0.1℃.
1995, 17(2): 215-219.
Abstract:
This paper reports the particle size effect on the resistance and TCR of Ta-doped Ru-base thick film resistor, which occurs when the particle sizes of two phases reach critical values (conductive phase 25nm, glass phase 50nm). And it can be explained qualitatively with the conduction mechanism of thick film resistor.
This paper reports the particle size effect on the resistance and TCR of Ta-doped Ru-base thick film resistor, which occurs when the particle sizes of two phases reach critical values (conductive phase 25nm, glass phase 50nm). And it can be explained qualitatively with the conduction mechanism of thick film resistor.
1995, 17(2): 220-224.
Abstract:
An airborne SAR real-time digital imaging processor is presented, and its real-time digital imaging principle and main technical parameters are analyzed briefly. The system configuration and logical structure are described in detail. Finally the main features of this system and examples of imagery obtained with the system are also presented.
An airborne SAR real-time digital imaging processor is presented, and its real-time digital imaging principle and main technical parameters are analyzed briefly. The system configuration and logical structure are described in detail. Finally the main features of this system and examples of imagery obtained with the system are also presented.
1995, 17(2): 175-181.
Abstract:
Over past ten years, the Ku-band broadcasting satellites had been sent into orbit by some countries and regions such as Japan, Western Europe and Northern America, etc. Also, a series of business for Direct Broadcasting Satellite (DBS) had been carried out. Those situations have accelerated the development of the receiving techniques for television broadcast by satellites, especially, the development of the small-size planar antennas. This paper discusses the basic principle, construction and features of small-size planar antennas. This paper also gives some technical parameters of the small-size planar antenna developed both at home and abroad. On the basis of the microstrip antenna, this paper summarizes all sorts of small- size planar antennas presented at several countries. At last, this paper explores the necessity to develop small-size planar antenna in our country and proposed the current urgent task for us to do.
Over past ten years, the Ku-band broadcasting satellites had been sent into orbit by some countries and regions such as Japan, Western Europe and Northern America, etc. Also, a series of business for Direct Broadcasting Satellite (DBS) had been carried out. Those situations have accelerated the development of the receiving techniques for television broadcast by satellites, especially, the development of the small-size planar antennas. This paper discusses the basic principle, construction and features of small-size planar antennas. This paper also gives some technical parameters of the small-size planar antenna developed both at home and abroad. On the basis of the microstrip antenna, this paper summarizes all sorts of small- size planar antennas presented at several countries. At last, this paper explores the necessity to develop small-size planar antenna in our country and proposed the current urgent task for us to do.
