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1983 Vol. 5, No. 6
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1983, 5(6): 333-342.
Abstract:
The geometrical relationship between the synthetic aperture radar (SAR) and its an-tenna coordinate system is reviewed briefly. The ideal aperture current distribution of SAR antenna is discussed in theoretical sense. On the basis of results derived by R. C. Heimiller (1962) and R. W. Bayma (1975), the effects of current distribution not in phase on the pattern of synthetic array and the Doppler-delay response are further analysed, and the numerical results calculated in the case of quadratic and cubic phase distributions are given. These results show that such phase distributions will cause the gain of synthetic array and the signal to ambiguity ratio of Doppler-delay response to be decreased. In consideration of these effects, the author proposes his additional remarks on the range of repetition frequency given by R. W. Bayma (1975).
The geometrical relationship between the synthetic aperture radar (SAR) and its an-tenna coordinate system is reviewed briefly. The ideal aperture current distribution of SAR antenna is discussed in theoretical sense. On the basis of results derived by R. C. Heimiller (1962) and R. W. Bayma (1975), the effects of current distribution not in phase on the pattern of synthetic array and the Doppler-delay response are further analysed, and the numerical results calculated in the case of quadratic and cubic phase distributions are given. These results show that such phase distributions will cause the gain of synthetic array and the signal to ambiguity ratio of Doppler-delay response to be decreased. In consideration of these effects, the author proposes his additional remarks on the range of repetition frequency given by R. W. Bayma (1975).
1983, 5(6): 343-349.
Abstract:
An algebraic complete decoding of double-error-correcting binary BCH codes is shown in this paper. It is faster than Hartmann s decoding of double-errcr-correcting binary BCH eodes of primitive length. And when the weight of the error pattern corresponding with synlromes S1 and S3 is equal to 3, this deeoding can find all error patterns of weigth 3 with the same syndromes. On the other hand, a discrimination of judging whether or not a cubie equation over GF(2m) has three distinct roots in GF(2m) is also shown in this paper. It is very improtant in the complete decoding of triple-error-correcting binary BCH codes.
An algebraic complete decoding of double-error-correcting binary BCH codes is shown in this paper. It is faster than Hartmann s decoding of double-errcr-correcting binary BCH eodes of primitive length. And when the weight of the error pattern corresponding with synlromes S1 and S3 is equal to 3, this deeoding can find all error patterns of weigth 3 with the same syndromes. On the other hand, a discrimination of judging whether or not a cubie equation over GF(2m) has three distinct roots in GF(2m) is also shown in this paper. It is very improtant in the complete decoding of triple-error-correcting binary BCH codes.
1983, 5(6): 350-359.
Abstract:
Quadrature-Amplitude Modulated (QAM) systems, Fractionally-Spaced Equalizer (FSE) that are for high speed data transmission over voice-band telephone lines are presented. The Kalman, fast Kalman, and adaptive lattice algorithms using a least square cost function to above systems are discussed. The paper concludes with the section about implementation approaches.
Quadrature-Amplitude Modulated (QAM) systems, Fractionally-Spaced Equalizer (FSE) that are for high speed data transmission over voice-band telephone lines are presented. The Kalman, fast Kalman, and adaptive lattice algorithms using a least square cost function to above systems are discussed. The paper concludes with the section about implementation approaches.
1983, 5(6): 360-364.
Abstract:
The problems of non-linear voltage response of the high-frequency detector are analy-sed and discussed. And also, the methods of dynamical detecting of the linearity of a detector and the quantitative design of its linearity are presented.
The problems of non-linear voltage response of the high-frequency detector are analy-sed and discussed. And also, the methods of dynamical detecting of the linearity of a detector and the quantitative design of its linearity are presented.
1983, 5(6): 365-374.
Abstract:
A set of eqaations for varactor tuning Grunn Diode Oscillator is derived by quasi-sinusoidal method. By special treatment of the nonlinear element, a program is obtained. With this program the small signal and large signal statistic tuning performance, dyna-mic behavior and transient response can be calculated.
A set of eqaations for varactor tuning Grunn Diode Oscillator is derived by quasi-sinusoidal method. By special treatment of the nonlinear element, a program is obtained. With this program the small signal and large signal statistic tuning performance, dyna-mic behavior and transient response can be calculated.
1983, 5(6): 375-381.
Abstract:
This paper shows that the state of magnetization of the substrate is one of the main fac-tors affecting the properties of nonreciprocal latching ferrite microstrip phase shifter. Rai-sing the residual magnetization of the substrate, increasing the ratio R =4M/(4Ms) (4M-the magnetization of the latching state of the device, 4Ms-the saturation magnetization) are effective in reducing the insertion loss of the device, raising the effective-ness of phase shift, extending the frequency range of the device,and reducing the drive power, etc. Different ways of magnetization are analysed and compared. Photos indicating the structure and external form of the device are given and the main performances of singledigit and multidigit devices are also presented.
This paper shows that the state of magnetization of the substrate is one of the main fac-tors affecting the properties of nonreciprocal latching ferrite microstrip phase shifter. Rai-sing the residual magnetization of the substrate, increasing the ratio R =4M/(4Ms) (4M-the magnetization of the latching state of the device, 4Ms-the saturation magnetization) are effective in reducing the insertion loss of the device, raising the effective-ness of phase shift, extending the frequency range of the device,and reducing the drive power, etc. Different ways of magnetization are analysed and compared. Photos indicating the structure and external form of the device are given and the main performances of singledigit and multidigit devices are also presented.
1983, 5(6): 382-387.
Abstract:
A series of curves of the photoconduction response under different field strengths and different degrees of illtimination has been measured and investigated. It is found that the rise and decay curves are abnormal under weaker fields. Analysis of these curves of photoconduction response shows that either rise curves or decay curves are composed of a spike-like and a quasi-exponential form. Considering the above fact, we suggest that these pheno-mena are due to the changes of distribution of the space charge in-Si:H films, when illumination turns on or off. It is felt that this paper is of universal significance for photosensitive materials with low mobilities and high resistivity.
A series of curves of the photoconduction response under different field strengths and different degrees of illtimination has been measured and investigated. It is found that the rise and decay curves are abnormal under weaker fields. Analysis of these curves of photoconduction response shows that either rise curves or decay curves are composed of a spike-like and a quasi-exponential form. Considering the above fact, we suggest that these pheno-mena are due to the changes of distribution of the space charge in-Si:H films, when illumination turns on or off. It is felt that this paper is of universal significance for photosensitive materials with low mobilities and high resistivity.
1983, 5(6): 388-395.
Abstract:
The effect of electron cyclotron frequency on the amplitude, output power, frequency, frequency spectrum, beam voltage and oscillatory region of the 8 mm H02 mode CRM-Mo-notron operating at second harmonic of the cyclotron frequency is studied. By keeping the electron cyclotron frequency in high stability, the frequency stability of the CRM-Mono-tron can reach 10-5, and the spectrum width and frequency drift are less than 1.5 MHz. Some useful data are provided for use of the CRM-Monotron.
The effect of electron cyclotron frequency on the amplitude, output power, frequency, frequency spectrum, beam voltage and oscillatory region of the 8 mm H02 mode CRM-Mo-notron operating at second harmonic of the cyclotron frequency is studied. By keeping the electron cyclotron frequency in high stability, the frequency stability of the CRM-Mono-tron can reach 10-5, and the spectrum width and frequency drift are less than 1.5 MHz. Some useful data are provided for use of the CRM-Monotron.
1983, 5(6): 396-400.
Abstract:
A method to test the stability of high lead glass CEM is made and some results are obtained. The life test datum with an accumulative count about 1011 is obtained; The stru-cture and composition of active surface of fatigued CEM are analyzed by using AES. We find the increase of carbon on the active surface is the main cause for the decrease of the CEM gain through the life test. The thicknese of contaminating carbon layer is approximately 50. In order to improve CEM s bake-resisting property, we have also studied theeffects of the baking temperature on the gain and FWHM, and the relationhip between the baking temperature and the reduction temperature. we find, on condition of keeping the resistivity constant at a certain time, the higber the reduction temperature, the higher the bake-resisting temperature is.
A method to test the stability of high lead glass CEM is made and some results are obtained. The life test datum with an accumulative count about 1011 is obtained; The stru-cture and composition of active surface of fatigued CEM are analyzed by using AES. We find the increase of carbon on the active surface is the main cause for the decrease of the CEM gain through the life test. The thicknese of contaminating carbon layer is approximately 50. In order to improve CEM s bake-resisting property, we have also studied theeffects of the baking temperature on the gain and FWHM, and the relationhip between the baking temperature and the reduction temperature. we find, on condition of keeping the resistivity constant at a certain time, the higber the reduction temperature, the higher the bake-resisting temperature is.
1983, 5(6): 401-406.
Abstract:
For a long time Mo-Mn metallization with Ti-powder coating ceramicmetal sealing technologies have been used in the production of vacuum devices. But these technologies are quite complex and the sealing quality is hardly guaranteed. Some reseaches on the direct sealing technology using Ti-Ag-Cu active alloy solder are carried out, with the influence of the content of the active element Ti, the sealing temperature and other parameters on the seal quality suitably investigated. Suitable Ti content in the alloy solder and specifications for sealing are given . The experimental results prove that the direct sealing technology using Ti-Ag-cu alloy solder is not complex and seal quality is stable.
For a long time Mo-Mn metallization with Ti-powder coating ceramicmetal sealing technologies have been used in the production of vacuum devices. But these technologies are quite complex and the sealing quality is hardly guaranteed. Some reseaches on the direct sealing technology using Ti-Ag-Cu active alloy solder are carried out, with the influence of the content of the active element Ti, the sealing temperature and other parameters on the seal quality suitably investigated. Suitable Ti content in the alloy solder and specifications for sealing are given . The experimental results prove that the direct sealing technology using Ti-Ag-cu alloy solder is not complex and seal quality is stable.
1983, 5(6): 407-408.
Abstract:
This paper presents a water-cooled are cathode operating in a condition of lowpressure continuous discharge. It has been used successfully in a full metal argon ion laser and an ion plating equipment.
This paper presents a water-cooled are cathode operating in a condition of lowpressure continuous discharge. It has been used successfully in a full metal argon ion laser and an ion plating equipment.
