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1988 Vol. 10, No. 6
Display Method:
1988, 10(6): 481-490.
Abstract:
In this paper, the problem how to reduce the GB effect in SC filter is discussed. A new general biquadratic SC structure in which the GB effect is reduced is developed. The structure is strays-insensitive, has very low W0and Q sensitivities. Using the low-pass SC filter for example, the method of reducing GB effect has been shown in detail.
In this paper, the problem how to reduce the GB effect in SC filter is discussed. A new general biquadratic SC structure in which the GB effect is reduced is developed. The structure is strays-insensitive, has very low W0and Q sensitivities. Using the low-pass SC filter for example, the method of reducing GB effect has been shown in detail.
1988, 10(6): 491-500.
Abstract:
A novel design of three-phase oscillator using switched-capacitor (SC) techniques is developed. Two classes of active RC prototypes are used to realize the switched-capacitor oscillators (SCO): one is the SD oscillator while the other is the three state variable oscillator. These SCOs have the following advantages: easily to be constructed in IC form, their oscillation frequency/clock frequency relationship being linear, and having the features of stray capacitance insensitivity and smaller capacitance ratio. The experimental results are in agreement with the theoretical ones.
A novel design of three-phase oscillator using switched-capacitor (SC) techniques is developed. Two classes of active RC prototypes are used to realize the switched-capacitor oscillators (SCO): one is the SD oscillator while the other is the three state variable oscillator. These SCOs have the following advantages: easily to be constructed in IC form, their oscillation frequency/clock frequency relationship being linear, and having the features of stray capacitance insensitivity and smaller capacitance ratio. The experimental results are in agreement with the theoretical ones.
1988, 10(6): 501-506.
Abstract:
The design principle is described for low frequency integrated operational amplifier XD1531 with low noise. The design procedures of both circuit and mask pattern are considered. The circuit structure of the first stage is designed with the methods for obtaining low noise at low frequency. The measures for decreasing the low frequency noise, especially the surface 1/f noise, are used for mask pattern design. By comparing its characteristics with those of other products at home and abroad, it is shown that XD1531 has lower noise in low frequency region than others and the design method is effective for bringing low noise.
The design principle is described for low frequency integrated operational amplifier XD1531 with low noise. The design procedures of both circuit and mask pattern are considered. The circuit structure of the first stage is designed with the methods for obtaining low noise at low frequency. The measures for decreasing the low frequency noise, especially the surface 1/f noise, are used for mask pattern design. By comparing its characteristics with those of other products at home and abroad, it is shown that XD1531 has lower noise in low frequency region than others and the design method is effective for bringing low noise.
1988, 10(6): 507-512.
Abstract:
A new method for measuring ocean wave length and direction from Seaset synthetic aperture radar (SAR) remote sensing image is presented in the paper. In the method, a ocean wave image is sampled in certain directions, the samples are then analyzed by using one dimensional Fourier transformation to calculate the ocean wave correlation function. At last the ocean wave length and direction are determined from the ocean wave correlation function. The method is better than the traditional two dimensional Fourier transformation method in both consuming time and precision.
A new method for measuring ocean wave length and direction from Seaset synthetic aperture radar (SAR) remote sensing image is presented in the paper. In the method, a ocean wave image is sampled in certain directions, the samples are then analyzed by using one dimensional Fourier transformation to calculate the ocean wave correlation function. At last the ocean wave length and direction are determined from the ocean wave correlation function. The method is better than the traditional two dimensional Fourier transformation method in both consuming time and precision.
1988, 10(6): 513-519.
Abstract:
An approximate formula of space charge field of orotron in rectangular coordinate system, when one of the boundaries is infinite, is derived. Using this model the self-consistent large signal interaction of orotron with space charge is calculated, and the effect of space charge on the performance of the device is discussed.
An approximate formula of space charge field of orotron in rectangular coordinate system, when one of the boundaries is infinite, is derived. Using this model the self-consistent large signal interaction of orotron with space charge is calculated, and the effect of space charge on the performance of the device is discussed.
1988, 10(6): 520-527.
Abstract:
Based on the relativistic general trajectory equations solved by the tensor method in a Frenet lecal coordinate system, considering the characteristics of wide electron beam focusing possessing a cathode surface, equations of the principal trajectory and the curvilinear paraxial trajectory are deduced. The characteristics of the curvilinear paraxial system satisfying the orthogonal condition are studied. Problems concerning narrow electron beam focusing or non-relativistic wide electron beam focusing in a curvilinear coordinate system can be regarded as special cases thereof.
Based on the relativistic general trajectory equations solved by the tensor method in a Frenet lecal coordinate system, considering the characteristics of wide electron beam focusing possessing a cathode surface, equations of the principal trajectory and the curvilinear paraxial trajectory are deduced. The characteristics of the curvilinear paraxial system satisfying the orthogonal condition are studied. Problems concerning narrow electron beam focusing or non-relativistic wide electron beam focusing in a curvilinear coordinate system can be regarded as special cases thereof.
1988, 10(6): 528-535.
Abstract:
a-Si:H vidicon targets based on the blocking structure have been deposited and investigated. The target current-voltage characteristics in dark and under illumination are measured. The photosensitivity is 2400 uA/lm. The spectral sensitivity is high over the whole visible range. The peak photoconductive gain is close to 0.8 at around 5800 A wavelength. The signal current increases linearly with light intensity, r is about 0.95. The dark current is about 1-3 nA at operating target voltage. The limiting resol...
a-Si:H vidicon targets based on the blocking structure have been deposited and investigated. The target current-voltage characteristics in dark and under illumination are measured. The photosensitivity is 2400 uA/lm. The spectral sensitivity is high over the whole visible range. The peak photoconductive gain is close to 0.8 at around 5800 A wavelength. The signal current increases linearly with light intensity, r is about 0.95. The dark current is about 1-3 nA at operating target voltage. The limiting resol...
1988, 10(6): 536-540.
Abstract:
Target identification by its complex natural frequencies is considered the one of the mosi prospective methods. However, the tolerance of SNR and the real-time behaviour of the method can not be met simultaneously in the process of extracting the frequencies from target s pulse response. In this paper, an aproach algorithm for the natural frequencies detection are proposed. The algorithm is still efficient in case of SNR=0dB, and takes only tens millisecond.
Target identification by its complex natural frequencies is considered the one of the mosi prospective methods. However, the tolerance of SNR and the real-time behaviour of the method can not be met simultaneously in the process of extracting the frequencies from target s pulse response. In this paper, an aproach algorithm for the natural frequencies detection are proposed. The algorithm is still efficient in case of SNR=0dB, and takes only tens millisecond.
1988, 10(6): 541-544.
Abstract:
Theoretical formula for determining the power spectrum of the scintillation radio-wave signal with interferometer is presented in this paper for study of ionosphere. The results of theoretical calculation agree will the measurements. The radio scintillation power spectrum index (p=3.5) which is caused by the irregularities in the ionosphere is determined from the results.
Theoretical formula for determining the power spectrum of the scintillation radio-wave signal with interferometer is presented in this paper for study of ionosphere. The results of theoretical calculation agree will the measurements. The radio scintillation power spectrum index (p=3.5) which is caused by the irregularities in the ionosphere is determined from the results.
1988, 10(6): 545-550.
Abstract:
An analysis technique----quasi-TEM wave analysis for gap discontinuity insuspended stripline is proposed. On either side of the discontinuity, the gap discontinuities with the same structure are inserted at equal spacing so that periodic discontinuity arrangement is constructed. The periodic length is so chosen that the interactions beween adjacent discotinuities vanish. A periodic range of them is analyzed. Its total capacitance is calculated by the two-dimensional Fourier transformation technique, from which the equivalent parameters of the discontinuity is obtained. when the suspended stripline degenerates into the stripline, numerical results are in agreement with the given by R. S. Yahya, et al. (1974).
An analysis technique----quasi-TEM wave analysis for gap discontinuity insuspended stripline is proposed. On either side of the discontinuity, the gap discontinuities with the same structure are inserted at equal spacing so that periodic discontinuity arrangement is constructed. The periodic length is so chosen that the interactions beween adjacent discotinuities vanish. A periodic range of them is analyzed. Its total capacitance is calculated by the two-dimensional Fourier transformation technique, from which the equivalent parameters of the discontinuity is obtained. when the suspended stripline degenerates into the stripline, numerical results are in agreement with the given by R. S. Yahya, et al. (1974).
1988, 10(6): 551-557.
Abstract:
An optimal design of the switched-capactitor network (SCN) in the biquadratic state-space is developed in this paper. Only n/2 states are needed to describe n-state filters in the design, so that many storages can be saved. After discussing the stability of the circuits in detail, the stable conditions which differ from EL-Masry (1981) are given. The optimum design of networks is made by the parameter freedom which exists during the design of the circuits. And an example is given for proving the corectness of this design method.
An optimal design of the switched-capactitor network (SCN) in the biquadratic state-space is developed in this paper. Only n/2 states are needed to describe n-state filters in the design, so that many storages can be saved. After discussing the stability of the circuits in detail, the stable conditions which differ from EL-Masry (1981) are given. The optimum design of networks is made by the parameter freedom which exists during the design of the circuits. And an example is given for proving the corectness of this design method.
1988, 10(6): 558-562.
Abstract:
Based on GTO s turn-off theory, parameter design and production technology are studied. Its performance characteristic and doping profile are measured. A 500 A reverse-blocked power GTO is made by using domestic material, equipment and installatiins. The technological process can be applied to the mass production of GTO.
Based on GTO s turn-off theory, parameter design and production technology are studied. Its performance characteristic and doping profile are measured. A 500 A reverse-blocked power GTO is made by using domestic material, equipment and installatiins. The technological process can be applied to the mass production of GTO.
1988, 10(6): 563-567.
Abstract:
A new method is applied to characterize the defects in GaAs material (e.g. the absorption of EL2 centres). The method consists of transmitting a laser beam (=1.1-1.5 m) through the GaAs wafer of 4-8 mm thickness and 50 mm diameter. The image is received by the TOSHIBA 8844 camera and entered into the DATASUD computer image processing system. This image is displayed on a monitor permitting to observe the inhomogeneity (like cross, cells and volutes) of the EL2 and dislocation defects. This paper will introduce a specific image processing software for GaAs material, called ZHIMAG (ZHang IMAGe) and its applications in GaAs wafer. The software can be also applied to any other types of image processing.
A new method is applied to characterize the defects in GaAs material (e.g. the absorption of EL2 centres). The method consists of transmitting a laser beam (=1.1-1.5 m) through the GaAs wafer of 4-8 mm thickness and 50 mm diameter. The image is received by the TOSHIBA 8844 camera and entered into the DATASUD computer image processing system. This image is displayed on a monitor permitting to observe the inhomogeneity (like cross, cells and volutes) of the EL2 and dislocation defects. This paper will introduce a specific image processing software for GaAs material, called ZHIMAG (ZHang IMAGe) and its applications in GaAs wafer. The software can be also applied to any other types of image processing.
1988, 10(6): 568-571.
Abstract:
For testing the sensitivity of plumbicon used in x-ray camera a P20 type light source is required. There are two methods of getting P20 type light source: (1) The P20 type light source is composed of a mini-oscillotron, screen of which is coated with P20 type phosphor, and four power supplies. (2) The P20 type light source is obtained by adding three particular filters to an A light source. The performance of two sources obtained by different methods are compared.
For testing the sensitivity of plumbicon used in x-ray camera a P20 type light source is required. There are two methods of getting P20 type light source: (1) The P20 type light source is composed of a mini-oscillotron, screen of which is coated with P20 type phosphor, and four power supplies. (2) The P20 type light source is obtained by adding three particular filters to an A light source. The performance of two sources obtained by different methods are compared.
