摘要:

AbstractBy making use of the matching characteristics of a rising‐sun type dual photodiode, an optically modulated photo‐IC with an improved external light illumination allowance was developed. In this photo‐IC, the frequency response of the preamplifier of one of the photodiodes is kept low. Only the dc component of the incident photo‐current is current‐voltage transformed and its output is applied by the current feedback to the preamplifier of another photodiode so that the external photocurrent is compensated automatically.In this method, the size ratio of the two photodiodes is compensated by the ratio of the gain resistance and the feedback resistance of the preamplifier. Hence, by the amount of the diode size ratio, the saturation characteristic of the preamplifier has a margin. The external light illumination allowance is improved by the corresponding amount. The minimum receiving sensitivity of the fabricated optically modulated photo‐IC was as small as 50 1x and its external light illumination allowance was as high as 20,000 1x. This circuit technique can be applied to various circuit systems which must be operated under bright environment described in the foregoing. Hence, its application to a system operated from outside a room

ISSN:8756-663X    

DOI:10.1002/ecjb.4420730901

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

年代:1990

数据来源: WILEY

摘要:

AbstractSince the signal obtained in the NMR Fresnel transform technique is given by an equation similar to that of the Fresnel diffraction equation in light, a technique in which the NMR signal in the Fresnel transform technique is recorded on a transparent film as a hologram and an image is reconstructed from such a hologram by using coherent laser light. Theoretical and experimental studies on such a technique are made in conjunction with the comparison between this technique and another technique in which the hologram is made from the NMR signal in the conventional Fourier imaging technique.The experiments show that considerably good quality images are reconstructed from the holograms in 16 shades of gray made from the signals in the NMR Fresnel transform technique since the dynamic range of the signal in this technique is small. This results in a quantization of the signal with little loss of the information, and the fringe pattern of the hologram is distributed widely over the hologram plane.The experiments show also that it is difficult to reconstruct good quality images from the holograms in 16 shades of gray made from the signals in the NMR Fourier transform technique. This is because most of the information of the image is lost by a quantization of the signal in such a small number of shades of gray since the dynamic range of the signal in the NMR Fourier transform technique is extremely large.It is shown also that the dynamic range of the signal can be decreased using a quadratic nonlinear field gradient in the pulse sequence in the NMR Fourier transform technique, and great improvement in the quality of the optically reconstructed image is obtained.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420730902

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

年代:1990

数据来源: WILEY

摘要:

AbstractResonant frequencies and the unloadedQ's of an axially symmetric resonator are calculated via a finite element method using three magnetic field components. In general, triangular elements are used in the finite element method. However, such elements are not necessarily convenient since the computational accuracy is degraded for the resonant modes with circumferential modal number of 0 or 1.In this paper, such difficulty is resolved by introduction of axial elements near the center axis. To reduce computation time, infinite elements also are introduced. The resonant frequencies actually are computed for dielectric disk resonators placed in a parallel plate cutoff waveguide and a conducting cylindrical cavity. It is confirmed that the computed results agree well with measured results or other available computed data.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420730903

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

年代:1990

数据来源: WILEY

摘要:

AbstractAn analysis algorithm is presented for the scattered field from a surface relief‐type anisotropic dielectric grating with an arbitrary permittivity tensor. The method based on the differential equation known widely as an analysis for isotropic dielectric gratings is extended here to the case where a dielectric grating contains an anisotropic medium.Further, an algorithm is proposed which avoids, by means of reorthogonalization of the initial value vectors, the difficulty in numerical treatment encountered by the differential method when the groove in the grating is deep and the number of expansion terms is large. By means of numerical examples, it is shown that stable numerical solutions can be obtained regardless of the depth of the grating grooves or the size of the expansion term

ISSN:8756-663X    

DOI:10.1002/ecjb.4420730904

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe nonradiative dielectric waveguide (NRD guide) which has low loss and no radiation at the bends and discontinuities is suitable for millimeter‐wave integrated circuits. In this paper, the NRD guide circuit components using beam‐lead diodes are studied in the 35‐GHz range.The diode mount proposed in this paper consists of a patch antenna and an RF choke etched together on a thin Teflon substrate. A beam‐lead diode is mounted on this structure and the substrate is inserted transversely in the dielectric waveguide. Since this mount has a compact and rigid structure and can be fabricated only by etching, no fabrication difficulty is expected at higher frequencies.A simple matching technique, which uses a thin high‐permittivity sheet and an air gap provided in the dielectric strip, is developed. The performance of a Schottky‐barrier diode detector, a balanced mixer, and a PIN diode pulse modulator were found to be quit

ISSN:8756-663X    

DOI:10.1002/ecjb.4420730905

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

年代:1990

数据来源: WILEY

摘要:

AbstractWith the advance of high‐speed LSI memory devices, a longer testing time is required for accurate measurement of the access time. For accurate testing, the accuracy of the access time measurement must be improved. Although the timing accuracy of the memory tester has been improved, the accuracy of the measurement is still insufficient for testing high‐speed devices.This paper considers the chip‐select access time of the high‐speed MOS static RAM (SRAM), and proposes a method for accurate measurement using a commercial memory tester. The input signal forcing‐time to the SRAM under measurement is corrected considering the GND bounce generated by SRAM.The transmission line is terminated on the load side by the same resistance as the characteristic impedance of the transmission circuit, so that the ringing is reduced in the pulse transmission from the SRAM output terminal to the memory tester comparator.Comparing the output data with ringing suppression and the output waveform under the standard output loading, the access time select point is determined. Applying the proposed method to the commercial memory tester, the chip‐select access time is measured with the expected accuracy of 1 ns or less. To realize a further accurate measurement, several points are raised concerning the design of high‐s

ISSN:8756-663X    

DOI:10.1002/ecjb.4420730906

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

年代:1990

数据来源: WILEY

摘要:

AbstractWith the recent development of computers, it has become possible to design a circuit by computer (CAD), which is very convenient and labor‐saving for the circuit designer. It is more beneficial from the viewpoint of time and money in the design stage to examine the operation and performance of the circuit by simulation rather than by experiment.On the other hand, in the analysis of the switching circuit, different circuit equations in the same number as the number of states must be solved, according to whether the switches are on or off. Consequently, the analytical procedure is very complex and lengthy.With this background, this paper proposes a new method for the analysis of the switching circuit in the frequency domain, using eigenvalues and eigenvectors. Using the case of analysis of Ćuk converter and a step‐down switched capacitor transformer as examples, the proposed method is compared with the conventional state‐space averaging method.The validity of the proposed method is demonstrated and has the following features: (1) the strict solution is derived for each state equation through z‐transform. Consequently, a more accurate result of analysis is obtained than by the state‐space averaging method; (2) it is not required to derive an equivalent circuit with state‐space averaging, as in SPICE2; and (3) only the final value of the state is calculated using the eigenvalues and eigenvectors. This reduces the computation time compared with the method by numerical

ISSN:8756-663X    

DOI:10.1002/ecjb.4420730907

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

年代:1990

数据来源: WILEY

摘要:

AbstractTo increase the radiation hardness of a quartz resonator, the sweeping process of a quartz is essential. This paper describes the influence of sweeping on defects and impurity density, and radiation hardness of a high‐purity synthetic quartz. Sweeping converts an Al‐M+type defect to Al‐OH−defect, where M+is an alkaline ion. The change in the defect type progresses from the positive electrode side to the negative electrode side.After sufficient sweeping, Al‐OH−defects are located uniformly over the entire quartz. The density of the impurity M+, which is removed by sweeping, is almost the same as that of the newly formed Al‐OH−‐type defects. It was confirmed experimentally that M+was replaced with OH−.The frequency change of a swept quartz resonator due to radiation is 100 times smaller than that of an unswept quartz resonator. It is on the order of 10−8when i

ISSN:8756-663X    

DOI:10.1002/ecjb.4420730908

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

年代:1990

数据来源: WILEY

摘要:

AbstractA recent study of the gas sensor device has been aimed at the improvement of gas selectivity and gas distinction. In the present study, to distinguish the kind of gas, three kinds of SnO2thin films with different resistivities were deposited on glass substrates by vacuum evaporation to evaluate the changes of resistivity and work function due to hydrogen and oxygen in a vacuum system. As a result, it was found that oxygen acts differently in vacuum than in atmosphere.From the results of these experiments by XPS and XRD, a model of oxygen and hydrogen adsorption was proposed. In hydrogen adsorption, the model of carrier release is adequate and in oxygen adsorption, the model of mobility increase is adequate.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420730909

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

年代:1990

数据来源: WILEY

摘要:

AbstractMemory cell design technology for highly reliable 256‐kb MNOS EEPROM has been established. It realizes 10‐year data retention and 105erase/write cycle endurance. An MNOS memory device is composed of a 24‐nm Si3N4layer and a 1.6‐nm tunnel SiO2layer. The programming voltage is 13 ± 1 V supplied from internal high‐voltage generator.A wide operating margin has been obtained in which the lower limit ensures the retention of the written state and the upper limit ensures the endurance of the erased state.Using 1.3‐μm CMOS fabrication technology, the data line pitch is 6.7 μm and the word line pitch is 7.8 μm. As a result, the MNOS memory cell size is designed to be 52.26 μm2, and the chip size is the smallest one such as 33.16 mm2i

ISSN:8756-663X    

DOI:10.1002/ecjb.4420730910

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

年代:1990

数据来源: WILEY