最新刊期
卷 ， 期 1 ， 1982
- 摘要：A proof is presented for the existence of the optimum burst-error-correcting irreducible Goppa codes whose burst-error-correcting capabilities arbitrarily approach the Wyner-Ash bound and Sharma-Dass bound for very large n. On the basis of this result, the asymptote of the burst-error-correcting on these irreducible Goppa codes is discussed. The result is that the most parts of the irreducible Goppa codes over GF（qm） have the burst-correcting capabilities n-k-nε/2≤b≤n-k/2, i. e. there are irreducible Goppa codes over GF （qm）, whoseburst-correcting capabilities are able to approach the Wyner-Ash bound, but the asymptote of the burst-correcting capabilities for these Goppa codes is no good, i. e. b/n may possibly approach zero, when n→∞, and R remains constant.4|38|1更新时间：2025-12-08
- 摘要：An alternative dispersion formula for monomode step-index weakly guiding optical fibers with more distinct physical insight is presented. Approximate expressions for u,du/ dv and d2u/dv2 are given in the range 1.5≤v≤3, which greatly simplified the calculation of both dispersion and zero-dispersion fiber parameters. The residual dispersion .and the influence of the difference between fused and quenched silica on total dispersion are also discussed.2|107|1更新时间：2025-12-08
- 摘要：Without using Darlington D type section, this paper gives a solution of realizing, without restrictive conditions, the complex transfer zeros for lossless network by means of three-element bridge sections and/or bridge sections without magnetic coupling, if it is desired to find a network from two given network parameters, such as Z11,Z12, or Y11,Y12.Each group of the complex transfer zeros may be realized by means of two sections in cascade: one is a bridge section, the other a previous section. The bridge section is used to produce the transfer zeros. This paper shows that the necessary and sufficient condition for using such bridge section as the input network is that the bridge section test value of the input impedance of the network is equal to zero. If the driving point impedance does not satisfy this condition, a previous section must be inserted. The previous section is an impedance transformation network, which transforms the driving point impedance to satisfy this condition. The previous section does not produce transfer zero. It is proved that the previous section may be a series branch section or a parallel branch section. This section does not contain more than two elements in general.A series of problems involved in the synthesis are discussed. The calculation method and formulas are given, which suit computer aided design. An example is given to illustrated the practical application of the method.2|14|2更新时间：2025-12-08
- 摘要：A numerical solution for open resonators with slow varying section waveguides is presented in this paper. By using this method, when the profile of the longitudinal section of an open resonator is given, the field distributions, the resonance frequencies and the ra-diational Q values may be calculated. Calculations based on this method have also been made for an open resonator with conical waveguides, and the relationship among the resonance frequencies and the parameters of the resonators, and the relationship among the radiational Q values and the parameters of the resonators have been obtained.2|124|9更新时间：2025-12-08
- 摘要：This paper proposes the so-called tree-structures method as an aid to realize design standardization based on "building blocks". Both the general-purpose and special-purpose tree-structures methods are presented, with the former intended for any functions, and the latter for given specific functions.2|12|2更新时间：2025-12-08
- 摘要：A set of general formulas for the evaluation of PN code self-noiso is given in this paper. The approximate formulas for engineering use are also given. Calculated Results by these formulas are very well in agreement with the results simulated by a digital computer. This shows that they can be used in PN code system design.2|23|0更新时间：2025-12-08
- 摘要：By describing a model of binary sequential detector realized on a computer, this paper systematically discusses the questions which are unavoidable in implementing a sequential detector for phased-array radar. The efficiency of sequential detection （two steps） is evaluated with retransmitting probability of beam-pointing. After obtaining the operating characteristics of the sequential detector, the relations among the retransmitting probability of beam-pointing, detectable signal-to-noise ratio and a detection threshold （or a quantization threshold） are quantitatively described, and the guideline for the rational use of radar’s energy is offered. Comparing the detection quality of sequential detection with that of density detection, the extent of improvement made by sequential detection for a radar is given. If the value of detection threshold （or quantization threshold） for the radar is properly selected, the sequential detection can improve the tracking ability by more than 3.4dB for the several detectors described in this paper, with a signal-to-noise ratio loss of 1.6dB only.2|76|6更新时间：2025-12-08
- 摘要：This paper describes dynamic drifts observed in integrated operational amplifiers. Experimentally it is found that there are two different mechanisms contributing to the dynamic drifts. One mechanism which is due to the thermal-electric feedback caused by output voltage swing is demonstrated and the other can be explained as ion drift caused by the common-mode input voltage.1|37|0更新时间：2025-12-08
- 摘要：The csc2 pattern of an equally-spaced linear array antenna with given amplitude excitation was synthesized. The phase distribution was derived by using the principles of stationary phase and sampling the results. Results of computations and experiments show that the maximum error of the synthesized pattern is about±3dB, and the level of sidelobe outside the region of beam-shaping is well below -15dB.An analysis also indicates that the csc2 pattern of planar phased arrays will become distorted in curls as it is scanned off from the broadside in azimuth.4|36|0更新时间：2025-12-08
- 摘要：In order to find out which metals cause s-pits in silicon epitaxial layers in ordinary production conditions, some of the pure metals, such as Fe, Cr, Cu, Au, and aqueous solutions of FeCl3, CuCl2 and NaCl were used for intentional contamination. The samples were <111>rientation, CZ dislocation-free silicon single crystal wafers. After such contamination, a hydrogen heat treatment or an epitaxy process was carried on at about 1200℃. It was observed that the contamination of Fe or FeCl3 always produced s-pits defects, and the same with Cr. But when the substrates were contaminated by Cu, Au, or NaCl, CuCl2, no s-pits were observed.Metals which cause s-pits in silicon epitaxial layers will produce the same defects in single crystal substrates.2|44|0更新时间：2025-12-08
- 摘要：The method of fault tree analysis is an efficient method for the reliability analysis of complex systems. For evaluating fault tree, first we ought to obtain its minimal cut sets by using a computer. There are many algorithms developed during the last ten years to deal with this problem. Their main goal is to obtain minimal cut sets as quickly as possible using the smallest amount of main core memory. But a lot of difficulties still exist. The method presented by this paper has thoroughly solved the problem of occupying too much memory space so that it is possible to evaluate a large and complex fault tree on a small computer.Having obtained the minimal cut sets, the next step is to calculate the failure probability. Improving and developing the methods of [5] and [7], this paper presents a method called circular cut transformation which can more easily transform the structure function into exclusive S-O-P form, it also has solved the problem of calculating Boolean Algebra on a compu-!er. The problem of calculating the failure probability of a large and complex system has been solved efficiently.2|97|6更新时间：2025-12-08
- 摘要：In the resonant transformerless switching-mode power supplies （TLSMPS）, the method of switchoff in the duration of zero current is applied. Consequently, as compared with chopper （PWM） type TLSMPS, it is possible to avoid the second breakdown, reduce the switching dissipation and radio frequency interference in the resonant TLSMPS.The operation of the power circuit of resonant TLSMPS is analyzed mathematically and the features of control are discussed in this paper. For solving the problem of stabilization in the control system of resonant TLSMPS, the technique of "forward" ripple feedback is proposed. Also, the existence of minor carrier storage effect in switching transistor of resonant loop is illustrated, and the impact of this effect is reduced.2|57|0更新时间：2025-12-08
- 摘要：In recent years, several papers have been published on active R notch filters containing only resistors and two operational amplifiers. However, they did not give design concepts for its circuits and the notch attenuation characteristics. Furthermore, the notch attenuation can not be adjusted with these simple filter structures. In this paper, basic thoughts of designing active R filters with two operational amplifiers are first presented. A new active R notch filter with two operational amplifiers and seven resistors is then given. This filter has very low sensitivities to all passive and active parameters, and is suitable for medium-Q high-frequency applications with its notch characteristic being adjustable. At the end of the paper an illustrative example is given. Laboratory experiments have confirmed the theory.It should be pointed out that the circuit presented in this paper may also be used to realize band-pass, low-pass, high-pass or all-pass transfer characteristics at its two different outputs.2|117|9更新时间：2025-12-08
- 摘要：A new kind of electronic medical instrument-microwave acupuncture-machine is reported. With the use of a specially designed acupuncture antenna, this instrument can produce 4 therapeutic functions by radiating quantitative and directional microwave beams to some acupuncture points on a patient’s body. The instrument has found applications in medical fields with a relatively good efficacy.2|66|2更新时间：2025-12-08
- 摘要：A thermal standard noise, gas discharge noise generators and a calibrating radiometer for 4mm band are discussed. Advantages and weak points of both the total-power and Dicke radiometers are evaluated. A calibrating system of total-power radiometer with IF attenuator has been set up, and its equalization and error equations are derived and analysed in this paper. An advantage of this system is that it can be used in all frequency bands. Furthermore, it uses fewer waveguide components, and the microwave precision attenuator can be substituted by a precision IF attenuator. This is of practical significance for millimeter and submillimeter bands. This system, when used to calibrate gas discharge noise generators, gives an excess-noise ratio of 16.2 dB, the total error being ±0.45 dB. If the accuracy of the IF attenuator is 0.02 dB, the total crror will be ±0.3 dB.2|26|0更新时间：2025-12-08
- 摘要：An airborne remote sensing CCD imaging and transmission system is described, and the imaging expressions are derived. Based on the MTF of a practical imaging system, we have developed an formula for the ratio of signal-to-quantizing noise in delta modulation. The experimental results are also given in this paper.7|31|0更新时间：2025-12-08
- 摘要：The methods are presented for designing wideband hybrid junction in UHF band. The cheoretical and experimental results for S. W. R. and isolation are given. Practice shows that this form of hybrid junction possesses good operational characteristics.2|102|0更新时间：2025-12-08
- 摘要：The differential phase shiftes back-ridged waveguide phase shifter is discussed. A correctional coeffecient is introduced into the phase constant transcendence eguation （17） of [1]. The results calculated have been proved to be good agreement with experiment.4|33|5更新时间：2025-12-08
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