摘要:

AbstractIn accordance with the recent tendency of miniaturizing failure with active elements, the non recursive transversal CTD (Charge Transfer Device) filters and the recursive CTD filters by means of the signal delay effect of CTD's have been analyzed and constructed. Comparing the latter with the former, a faster frequency response can be realized with less order although there exists a stability problem due to the poles produced by the recursive loop of the circuit. The recursive circuit is suitable in realizing a high‐Q single‐tuned bandpass filter. In this paper, a design method for the single‐tuned bandpass filter with CTD having higher stability against Q variation than that of the conventional second‐order CTD filters [6, 7] is presented. Assuming a pole and a zero which can move along the prescribed closed loci on the Z‐plane depending on the input frequency, the low coefficient sensitivity transfer function is obtained and an economical canonic form circuit is realized. A consideration on the proposed concept that poles and zeros can move corresponding to the input frequencies is presented in the Appendix and the experimental confirmation

ISSN:8756-6621    

DOI:10.1002/ecja.4400630402

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

年代:1980

数据来源: WILEY

摘要:

AbstractTraditionally, the use of nonuniform transmission lines has been suggested for designing a wideband impedance transformer. However, no rigorous design method has been found. This paper proposes two rigorous methods each for designing distortionless, nonreflective all‐high‐ and low‐impedance transformers which are simple and of minimum attenuation, based on the distortionless conditions of the voltage and current waveforms in a nonuniform transmission line. The methods make only C(x) or L(x) of the primary constants of the transmission line uniform. It was found sufficient that these distributions be of square or inverse square. According to the design method, we designed a 50 to 75 ω transformer which is subsequently modeled by a 100‐stage ladder network. We performed experiments in the dc ‐ 10 MHz frequency domain as well as in the time domain. The experiment has been proceeded in accordance with the theory and the effectiveness of the proposed design method and the validity of the distortionless theory of nonuniform transmission line

ISSN:8756-6621    

DOI:10.1002/ecja.4400630403

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

年代:1980

数据来源: WILEY

摘要:

AbstractThis paper proposed two methods (the decision theory method and the probability method) for estimating the approximate magnitude of the tolerances of the transfer characteristics which are caused by the deviation of elements of a reactance filter. The first method estimates the total element sensitivities of the filter by an estimation measure which gives an upper bound of the absolute sum of the second‐order element sensitivities for the attenuation characteristic of the reactance filter. The estimation measure is represented by the various quantities which can be derived from the characteristic function of the filter only. Therefore, the element sensitivities of the filter can be estimated by its characteristic function only before actually constructing the network. The second method is for determining the statistical mean value and variance of the tolerance of the transfer characteristics for a reactance ladder filter. A calculation algorithm for this method is proposed. The transfer characteristics include the attenutation characteristic and phase characteristic as well as the real and imaginary parts of the characteristic function expressed in nepers. The analytical technique is based on Taylor's series expansion. The first‐order to third‐order terms and the mean value of the fourth‐order term are used. The second method differs from the first in that the former utilizes the information about the internal structure of the

ISSN:8756-6621    

DOI:10.1002/ecja.4400630404

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

年代:1980

数据来源: WILEY

摘要:

AbstractIn human vision there occurs an interesting illusion called the Craik‐O'Brien effect. When a counter line has an appropriate distribution of brightness, even though there is no physical contrast, from the contour information a contrast is produced and an object can be seen. It is hoped that this visual phenomenon can be utilized by an engineering application to improve the quality of TV pictures and condensation of the transmission signals In the past, this phenomenon was studied as an illusion of brightness (no color), and the Craik‐O'Brien effect was not found in the case of color. Hence, its characteristics were unclear . Using an electric edge pattern generator and a color CRT, the author has in this case generated monochromatic colors (R, G, B) and hue edge patterns whose luminance is constant but of different colors and hues. The response of the subjects was measured by psychophysical methods. The results proved the existence of the Craik‐O'Brien effect in the case of chromatic counter information and the author elucidated its characteristics. In the case of monochromatic edge patterns, the effect is significant and its basic characteristic is close to that of the brightness Craik‐O'Brien effect. On the other hand, in the case of chromatic edge patterns, although the pattern existed, the contrast produced by the color was less significant when compared with the contrast produced by the brightness and was only a fraction of the contrast produced by the brightness Craik‐O'Bri

ISSN:8756-6621    

DOI:10.1002/ecja.4400630405

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe effects of a second harmonic resonance circuit on IMPATT oscillator characteristics have been investigated. The admittance of an IMPATT diode is measured using an injection locking method simultaneously at the fundamental and second harmonic frequencies. A computer analysis, approximating the p+nn+IMPATT structure with a Read diode, is carried out and the results are compared with the experiment. The theory agrees well with the experiment and has revealed characteristics of IMPATT diodes in the presence of an ac voltage component at second harmonic frequency. It is found that the negative conductance at the fundamental frequency is increased by properly selecting the load admittance at the second harmonic frequency. Characteristics of an IMPATT oscillator with a second harmonic resonance circuit at microwave and millimeter wave frequencies then are examined based on the computer simulation. The output power at the fundamental frequency varies over 10 dB when the second harmonic circuit conditions are varied near the resonance condition. The output power at fundamental frequency can be made a few decibels higher for optimized admittance at the second harmonic circuit than under off‐resonance conditions. Considerable output power at the second harmonic frequency is obtained under the above resonance conditions, and is described in detai

ISSN:8756-6621    

DOI:10.1002/ecja.4400630406

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

年代:1980

数据来源: WILEY

摘要:

AbstractIn the superconducting cavity stabilized oscillator (SCO), which has extremely high‐frequency stability, the power input to the superconducting cavity (SC) must be minimized since the energy stored in the SC causes a shift in the resonance frequency away from its value at zero stored energy due to the electromagnetic radiation pressure and nonlinear surface reactance. Therefore, in the SCO with self‐injection locking, a loosely coupled directional coupler is used to couple a free running oscillator to an SC. This paper describes the design of self‐injection‐locked SCO's.The effects on frequency stability of the SC coupling factor and electrical line length between the SC and oscillating device are discussed. Oscillation frequency is given as a function of electrical line length. Optimum line length is discussed and the stability criteria for the oscillating device are derived. Based on this design consideration, an X‐band Gunn effect oscillator is stabilized. The SC is fabricated from solid Nb and has an unloaded Q‐factor of 6.7 × 106. The noise floor of frequency stability as low as 8.5 × 10‐11ha

ISSN:8756-6621    

DOI:10.1002/ecja.4400630407

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

年代:1980

数据来源: WILEY

摘要:

AbstractThis paper describes fabrication and characteristics of 10‐GHz‐band TM010‐mode superconducting cavities with electroplated lead films on the walls of press‐formed copper shells. The cavity is made up of two symmetrical pieces of copper, and rf current flows parallel to their joint planes. Homogeneous lead films are obtained on copper substrate by using a lead anode with a hemispheric projection. In order to make the rf joints in the cavity, either (a) lead wires were inserted between the copper subtrates with lead films, or (b) indium wires are used between copper substrates on which lead is electroplated. Temperature dependence of Q‐factors of the lead cavities was measured at low temperatures for input power less than 3 mW in an environment where terrestrial magnetism was compensated to be within 20 mG. Q‐factors on the order of 109were obtained for cavities prepared by the method (b). They also showed residual rf surface resistances as low as 2 × 10‐8ω, which is less than that of TE‐mode lead cavities reported so far for the sam

ISSN:8756-6621    

DOI:10.1002/ecja.4400630408

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe DPCM, a representative prediction encoding system of picture signals, produces two conflicting noises‐overload and granular. This paper describes the selective DPCM that separates picture signals into edge and slant components, and an optimum encoding is applied for each component to consider the two noises. First, statistical analyses on picture signals conclude that they are composed of the edge component and slant component. Second, the edge component, which shows frames of pictures, is approximated by step waves and the slant component, which shows the smoothness of pictures, is approximated by delta modulation. A new method is proposed here: a statistic adaptation in each block and a constant speed scanning are applied for input picture signals. Finally, it is demonstrated that computer simulations prove the usefulness of the metho

ISSN:8756-6621    

DOI:10.1002/ecja.4400630409

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

年代:1980

数据来源: WILEY

摘要:

AbstractIn a high‐speed PCM switching system, it is possible to achieve low blocking probability and high switching efficiency due to the large number of available time‐division paths between a given inlet and outlet pair. However, in order to achieve high efficiency, the central control processor of the system must perform more intensive path hunting. In conventional switching network design, the efficiency of the network is a prime concern while the control procedure for path hunting is often overlooked. Depending on the type of switching network, the trade‐off between the efficiency of the network and the complexity of the control procedure should be considered. The main purpose of this paper is to evaluate the path hunting procedures for T‐S‐T type of time‐division switching networks. The path hunting procedure will be evaluated on the basis of theoretical analysis and simulation of typical switching networks. It will be shown that there is a trade‐off between the efficiency of the network and the complexity of the cont

ISSN:8756-6621    

DOI:10.1002/ecja.4400630410

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

年代:1980

数据来源: WILEY

摘要:

AbstractIn a previous paper, the authors introduced a predictive partition coding scheme—CLAPEL—for the optimization of facsimile data compression using the correlation of neighboring picture elements (pels). In the 'present paper the relationship between the design parameters associated with the hardware scale and the compression factor is investigated. The input documents used in the simulation are the eight test documents recommended by the CCITT. The design parameters are varied; and the corresponding variations in the conditional entropy, the (compression) preserving factor, and the coding efficiency are observed. It is found that within the practical range of hardware scale, the preserving factor depends only on the number of modes if the number of reference pels is increased, and that the adaptive processing is not necessary during the predictive transformation. Several new coding schemes are examined in the examples which indicate that the coding efficiency has a tendency to decrease as the hardware parameters grow. Thus, the relationship between the hardware design parameters and the compression factor is clarified. The objective of this paper is to investigate the data compression factor without considering the processing times of the input and output devi

ISSN:8756-6621    

DOI:10.1002/ecja.4400630411

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

年代:1980

数据来源: WILEY