摘要:

AbstractBecause of its orthogonal flux control system, the ferrite orthogonal core holds promise as a vector sensor. The combination of such a core and a magnetic fluid is of interest for control of flux with a simple system.The results of experimental studies comparing vertical and tilted ferrite orthogonal cores in magnetic fluid indicate that the system can be used as a two‐dimensional inclinosenso

ISSN:8756-663X    

DOI:10.1002/ecjb.4420700601

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractMobile satellite communication systems employ the wide area accessibility of a satellite. Digital signal transmission systems which enable communication by highly efficient voice encoding techniques and error correcting techniques, even on lowC/Nchannels, are being studied and developed in many countries. This paper studies error rate monitoring for application to antenna tracking control and transmitting power control in mobile satellite communication systems. A soft decision error correction method, which is expected to be available in a wide range ofC/N, is proposed and its performance is clarified theoretically and experimentally. Considering the application to ship antenna tracking control, the monitoring accuracy on fading channels is evaluated experimentally. A simulation experiment is carried out for an electronic tracking control with switching arrays, and the reception level degradation due to tracking error is clarified. Simulation results of transmitting power control against rain attenuation are also given.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420700602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe oscillation spectral linewidth and the oscillation frequency of a laser diode with an external cavity have been stabilized simultaneously with an optical fiber ring resonator used as a spectrum discriminator. Stabilization of the oscillation spectrum linewidth has been carried out with control of the phase of the fed‐back light and the oscillation frequency by control of the injected current. The oscillation spectral linewidth is 2 MHz and its fluctuation is less than 10 kHzp‐pand the equivalent oscillation frequency fluctuation is 2 MHzp‐pFrom these results, it is confirmed that an external cavity laser diode can be used as a light source of a ring resonator‐type fiber gy

ISSN:8756-663X    

DOI:10.1002/ecjb.4420700603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractA solution based on a finite‐element method is proposed for calculation of the reflection and transmission characteristics of a finite periodic waveguide for elastic waves. Although finite‐element methods have already been applied to the discontinuity problem in an acoustic waveguide, it has not been possible due to excessive computation time and memory requirement to apply directly the finite‐element method to many discontinuities such as a periodic acoustic waveguide. In this paper, formulations have been undertaken with the substructure which is a related technology of the finite‐element method. Hence, the finite‐element method can be applied directly to all the discontinuities. As a result, in the finite periodic waveguides for acoustic waves, the mutual interaction of the surface wave and the bulk wave can be taken into account over all the discontinuities. The present method has been applied to a groove‐type grating reflector and the validity and effectiveness of the method has been confirmed by comparison with experimental results. An analysis has also been carried out for the positive and negative reflection‐type reflector proposed recently in which the grooves and ridges are combined. It has been confirmed numerically that this reflector has a larger reflection coefficient and smaller bulk wave conversion loss than the conventio

ISSN:8756-663X    

DOI:10.1002/ecjb.4420700604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractA theoretical method is described for determining equivalent circuit parameters for metallic gratings on arbitrary piezoelectric substrates. In this paper, to consider an energy storage effect, we adopt the equivalent circuit model proposed by Li et al. The finite‐element method is used to calculate the upper and lower cutoff frequencies of the stop band for metallic gratings of infinite periodic structure, and circuit parameters are determined from these values. Therefore, in this equivalent circuit, all the effects of piezoelectric perturbation, mechanical perturbation, and energy storage are taken into account. To show the validity and usefulness of this approach, for aluminum strips on some useful piezoelectric substrates (LiNbO3, quartz, LiTaO3, Li2B4O7), equivalent circuit parameters for each of the metallic gratings are determined and SAW reflection characteristics are computed. Result show that for the Li2B4O7substrate, the reflection magnitude per strip is large and the influence of the change of strip thickness on the center frequency shift is smal

ISSN:8756-663X    

DOI:10.1002/ecjb.4420700605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractDeformation of a small area (≤ 40 μm) on a magnetic disk (anodized Al‐alloy substrate with γ Fe2O3. sputtered surface) due to an external force was investigated. The results are that: (1) the amount of deformation (elevation or depression) on the surface of the disk is proportional to the load applied in the test. The elevation ratio α (amount of elevation/amount of depression; about 1 for a noncompressive material) has a similar trend, although its increase rate depends on the thickness of the anodized layer δ; (2) in the range of experimental load (≤ 50 g), α is greater than 1 when 6 is small (<10 μm), and α is smaller than 1 when δ is large. The former is caused by a plastic flow of the Al‐alloy onto the disk surface due to a crack on the anodized layer forming a porous scratch. In the latter, the anodized layer is hardly broken so that a plastic flow onto the disk surface is suppressed; and (3) the distribution of the stress in the substrate was analyzed by the finite‐element method. When δ is small (2 μm), the maximum tension‐stress and the maximum shear‐stress occur on the substrate surface; and when δ is large (11 μm), they occur near the boundary between the anodized layer and the Al‐alloy. These explain qualitatively the

ISSN:8756-663X    

DOI:10.1002/ecjb.4420700606

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractBa‐ferrite films were deposited by rfdiode sputtering which is one of the most conventional methods for complex oxide deposition and the applications of such films in perpendicular magnetic recording are discussed. Because of the bombardment by high‐energy particles, the composition of the deposited film was different from that of the target material. However, we were able to beam films with stoichiometric composition by adjusting the composition of the target. In one case, the first 300 Å layer had spinel‐type crystal structure and the layer above that initial layer had the structure of the magnetoplumbite type of Ba‐ferrite, oriented along thec‐axis. In the other case, the entire film was composed of the Ba‐ferrite layer oriented along thec‐axis. The result of investigating the growth conditions showed that the spinel layer caused a Δθ50dispersion of the growth orientation in the Ba‐ferrite layer away from thec‐axis. When the growth temperature was around 550°C, the growth occurred in the direction of thec‐axis. The surface roughness of the film was dependent on the distance between the target and the substrate, the partial pressure of oxygen, and the substrate temperature. At high oxygen partial pressures, the deviation of the growth orientation from thec‐axis was especially high, and the surface became rough. The best Ba‐ferrite film had the following properties: Δθ50= 2 to 3°,Hc1= 1.2 kOe andMs= 300 emu/cc. The film surface was smooth and hard enough to serve as a perpendic

ISSN:8756-663X    

DOI:10.1002/ecjb.4420700607

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractAn automatic inspection device has been developed for detecting chip components missing from or improperly positioned on printed wiring boards after the components have been attached temporarily with adhesive and then soldered. Errors are detected by illuminating the back of a mask with holes that correspond to the component locations against the board and observing light leakage. The locations of defect signals are displayed on a TV monitor and memorized as coordinates on a rectangular coordinate system that corresponds to the visual field of the TV camera to provide quantitative data on defect locations. Defect signals and external noise are recorded simultaneously for the first few frames. Succeeding frames are checked for a continuous signal to eliminate problems due to external noise. If a continuous signal is not detected, it is assumed that only noise exists. Device performance is as follows: 1) inspection time–2 s or less for boards with 500 chips or less; 2) inspection accuracy—±0.3 mm maximum. Although the simple structure of the device ensures low cost, the device is extremely effective in actual

ISSN:8756-663X    

DOI:10.1002/ecjb.4420700608

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractIn electronic measurement, industrial measurement, medical instrumentation and industrial control, there are several practical problems in dc amplifier characteristics such as initial offset voltage, temperature drift, time drift, noise and input bias current. In some applications, a dc amplifier with a good long‐term stability is required. This paper presents a method for realizing a dc amplifier suitable to these applications. After characteristics of the components used are matched as much as possible, a thermal feedback is introduced that suppresses the effect of the ambient temperature fluctuation. First, a model of the system is introduced and the thermal coupling stage of the first stage affecting the drift is analyzed so that the parameters necessary for suppression of the temperature drift are obtained. Next, this model is used for derivation of the degree of suppression of the drift by the present method. A method of selecting the parameters and a design procedure are discussed. It is found that the temperature drift can be suppressed by 40 dB at an extremely low‐frequency range in the test amplifier and the temperature coefficient is 0.36 μV/°C. At specific frequencies, the improvement is 16 dB at 0.27 mHz and 10 dB at 0.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420700609

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe dependence of the two‐dimensional oxidation of silicon on the temperature and the oxidation period was investigated. A (110) silicon wafer whose surface was step‐shaped by anisotropic etching was oxidized between 900 and 1150°C and the cross sections of the oxide layers at the upper and lower edges were observed by SEM. The numerical simulation of the oxide film growth was carried out by considering both the diffusion and the surface reaction at the Si/SiO2interface of the oxidants. The result was compared with the experimental result, and no orientation dependence in the growth rate was observed at high oxidation temperature. However, at the lower temperature, the growth rate in the (110) surface was higher than that in the (100) surface. This is believed to be due to the fact that the thermal oxidation at high temperature is diffusion‐dominated, while at the lower temperature, it is dominated by the surface reaction. In the low‐temperature oxidation at the upper edge, there was considerable decrease in the growth rate at the corners and the shape of the film was deformed. However, no such observation was made in the high‐temperature oxidation. The reason for this is believed to be the stress caused by the low‐temperature oxidation and the stress relaxation during high‐temperature oxidation. On the other hand, regardless of the oxidation temperature, the oxide film was deformed at the corners of the lower edge. This is believed to be caused by the deficiency

ISSN:8756-663X    

DOI:10.1002/ecjb.4420700610

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY