The equivalent circuit constants of a packaged IMPATT diode were precisely determined from measured impedance data employing numerical calculations. The errors included in the element values are estimated to be small from the comparison of the measured and the calculated input impedances of the circuits.

A symptotic equivalency between the adaptive array under directional constraint and the synthesized array with maximum directive gain subject to null constraint is proved analytically. (The analytical expression of the solution of the latter which has only been treated numerically is derived here.) Method of analysis is based on the orthogonal projection of a vector in the multidimensional space with properly chosen base. The results of adaptive and conventional methods are given in closed forms and their proportional relationship is shown obviously. Based on the characteristics of the adaptive array which gives the maximum output signal-to-noise ratio, its application to the pattern synthesis problem is investigated for the environment of various combinations of the interference and internal noise. Special emphasis is laid upon the case of super-gain phenomenon, where the angular separation between the desired signal and interference is very close. Even in this case, the adaptive technique does not require any introduction of additional parameters like Q-factor, but guarantees the optimum solution by virtue of its guiding principle. It is also shown that the adaptive technique always gives higher output signal-to-noise ratio than the conventional synthesis method. Some numerical examples are presented to prove the discussions clearly.

In this paper, we describe a method of determining the polarity of input terminals of the operational amplifiers which are represented with the nullator and norator model. A circuit containing nullators and norators can be realized by two types of DC stable circuit, one is the conditionally stable circuit and the other the absolutely one. The former is a circuit that, if the sequence of activating operational amplifiers is settled, is stable and the latter is one that is always stable. The necessary and sufficient condition of the absolutely stable circuit is also shown.

A widely used partial height ferrite circulator is analyzed. The circulator consists of ferrite post, dielectric spacers and a radial line stepped transformer, all of whose structures are assumed to be cylindrical. Eigenvalues of a circulator scattering matrix are numerically calculated, using mode matching method. Field analysis yields characteristics equations, which determine propagation constants in the partial height ferrite and dielectric structure. Calculated results of X-band circulators agreed well with experimental results. Wideband characteristics are obtained with numerical calculations.

An estimation method of rain rate distributions is described to facilitate estimation of rain attenuation in terrestial and satellite communication systems using frequencies above 10 GHz. The results of this research are summarized as follows. (1) Using observational data for rainfall, recorded by meteorological observatories located in various parts of Japan, data on rainfall differentiated by meteorological phenomena, such as thunderstorm rain, rain caused by typhoon and other sorts of rain and cumulative ten minute rain rate distribution were obtained. (2) Using meteorological data regarding rain and other factors provided by meteorological observatories at various locations throughout Japan, P % level of cumulative ten minute rain rate distribution Rp, total amount of rainfall per average year E, number of thunderstorm rain days per average year Dts and number of rain days per average year caused by typhoon Dt, were, obtained. A statistical analysis was carried out on these data, and the empirical formula for Rp was derived therefrom, using E, Dts and Dt as parameters. (3) Furthermore, using data regarding cumulative ten minute rain rate distribution for both one year and for the worst month at each location, the empirical formula was derived for relation between cumulative probability of rain rate for a year P(R)y and for a worst month P(R)wm for the same rain rate level.

An on-line automatic spoken word recognition system has been developed for the researches on the automatic recognition of speech. In this system, the spoken word is, first, converted into a time series of short time spectra by 29-channel filter bank of single tuned low selectivity filters. Three major local peaks in the spectrum and the power of the speech wave are extracted in every 10 ms. Input speech is transformed into some possible phonemic sequences by using three major local peaks and the speech power. The similarity of the sequence to every item of the word dictionary in the recognition system is computed. The item of the dictionary having the maximum similarity to the sequence is chosen as the output of the recognition. Some recognition experiments have been carried out with the system. In the interactive experiment, the recognition score was found to be 94% for 51 city names uttered by 25 male speakers arbitrarily chosen.

Field effect transistors in the high frequency region are most often made of GaAs which presents negative mobility. Electrons carried in the active channel of a device cannot escape the effect of the negative mobility. In this paper, the noise in FETs made of materials with negative mobility is studied. The effects of negative mobility can be summarized as follows. 1) It increases induced charge in the channel; 2) increases stationary carries, promoting the formation of noise dipoles and 3) amplifies the size of the noise dipoles as they travel along the channel. These effects will increase the values of equivalent noise conductances. At the same time, the correlation coefficient between the gate and drain noise currents peaks near pinch off, thus resulting in a low noise figure minimum. Calculations are supported by reported results. In the calculations, the effect of extending the depletion layer at the drain end of the gate is also considered in an attempt to attain more accurate values of signal parameters as well as of noise parameters.

This letter describes a method of withdrawing interdigital electrodes for sidelobe reduction of surface acoustic wave filters by using implicit enumeration algorithm for 0-1 type integer optimization. Obtained results, for example, show that the sidelobe level of 40.98 dB can be obtained by withdrawing 14 electrodes from each of the input and output transducers consisting of 51 electrode pairs. Since the implicit enumeration algorithm gives several sub-optimal solutions in addition to the optimal one, it may be useful for some practical filter design.

Transient numerical analysis of electrical signal injection into the surface CCD is given regarding the potential equilibration method. The analysis is composed of the charging and discharging processes of signal charges, characterized by time intervals TC and TD of the respective input pulses. A concept of setting time TS" explains how the mode of injection converts from the potential equilibration to dynamic injection, and determines a optimum TC . A concept of residual effect of excess charges" is discussed in relation to sampling effect. The procedure to determine a optimum TD is also proposed. It is concluded that the optimum TC and TD for completion of linear charge preset are determined by device geometry (that is, electrode lengths of the CCD input gates), while the TC also depends on the bias condition of the input pulses. The above conclusions can be applied to setting input pulses and the structure of CCD inputs designed for analog signal processing.

A novel piezoelectric electro-motional device using a PVF2 multilayer bimorph structure is described. This structure delivers a relatively large bending motion at low applied voltages because of the bimorph action and the thickness of the polymer films. Typically, the bending deflection at the unsupported end of a two-layer bimorph cantilever structure 20 mm in length is 1 mm per 10 volts of dc applied potential across the layers. Frequency response is typically 10 - 102 Hz depending upon cantilever length. Performance is relatively insensitive to temperature over the range 35 to 40. A large range of mechanical-electrical tradeoffs in relatively simple structures using inexpensive material makes these devices potentially attractive for a wide range of applications that require low frequencies and mechanical force, for example: for fine motion control, for displays, for light beam control, and for certain types of electrical circuit control.

A voltage-controlled current source, one of the controlled sources, has been used primarily for realizing the gyrators. This paper proposes a method of realizing an active RC filter using directly VCCS's as the active element. Also, this paper presents various circuits capable of obtaining the low-pass, band-pass, high-pass, and all-pass functions as typical applications.

Optimal channel graphs (least blocking probability), so far confined to those derived by parallel operations", are generalized for a simple 4-stage case. An optimum is materialized, and is assured to be superior to the former optimum.

Design theory for piezoelectric polymer membrane motional devices is presented. Three types of structures are considered: 1) multilayer structures with a central non-piezoelectric layer, 2) multilayer structures using layers with various thickness in which the electric field is expressed by a approximation of linear spatial dependence, and 3) single layer structures with interdigitated electrodes. The first and second structures feature a reduction in the number of layers with little reduction in motional performance. These approaches are advantageous for structural simplification. The third structure provides a 35 times larger bending displacement than that of the original double layer bimorph using the same layer thickness.

The efficient use of frequency spectrum is one of the most important problems in mobile radio communication systems. In a small zone system (the so-called cellular system), the algorithm used to make the channel assignment for a call has a great effect on system performance (traffic characteristics). This paper presents the relationships between the traffic-carrying capacity and the graph which represents the relation among a zone and its buffer zones in the system. Furthermore, using these relationships, an algorithm for the dynamic frequency (channel) assignment which has all channel available at all base stations is proposed. The performance characteristics of this algorithm obtained from computer simulations are also presented. The computer simulation treats the two examples (systems), one is the system in which the mobile units does not cross a zone boundary during a communication (the zone size is sufficiently large and the probability of the occurrence can be neglected.), the other is the system in which the mobile unit may cross a zone boundary during a communication. The results from these simulations show that the algorithm carries more traffic per channel at a given blocking rate than the RING method.

A new quick response rain gauge of waterdrop counting type with a wide measurement range from 0.7 up to 300 mm/H has been developed. From the result of the filed operation for 3 years, this gauge is proven to have the accuracy better than 10%.

Buried-heterostructure lasers (BH lasers), having a narrow active region and a low threshold current, oscillate stably in a single transverse mode in a wide range of driving currents above threshold. In addition, no significant kinks can be observed in the light output vs. current characteristics. Sinusoidal modulation characteristics of BH lasers are measured especially with respect to frequency response, spectrum broadening and nonlinear distortion. From experiments, it is exhibited that BH lasers have a flat frequency response up to 2 GHz, with less spectrum broadening than conventional wide stripe lasers, and a low 2nd-order distortion of about 50 dB below the fundamental level. This distortion is favourable when compared to LED's. These results demonstrate the feasibility of BH lasers as promising optical sources with linear and wideband modulation capabilities.

Algebraic properties of the set of regular states for a given hierarchically structured learning objectives are discussed. The set is proved to be a distributive lattice, if two operations, meet and join, are properly defined on it. The derived algebraic properties of the set are then applied to some of the procedures in the learning diagnosis and treatment (LDT) reported earlier.

The aim of this study is to establish a method for estimating rain attenuation distribution and site diversity effect for earth to satellite links using frequencies above 10 GHz. In the case of lognormal distribution of rain rate distribution, theoretical formulas for the rain attenuation distribution, as well as for the site diversity effect on slant propagation paths, have been derived in terms of rain rate distribution, rain rate spatial correlation function, raindrop layer height, and rain attenuation coefficient. Theoretical rain attenuation distribution function values have been compared with empirical values, which are based on 3 years observation by a sun-tracking radiometer at Musashino (Tokyo). Good coincidence has been recognized between them in the interval where the cumulative distribution function value is greater than 0.01%. Regarding site diversity effect, comparison of theoretical values has been made, not only with the empirical values in Japan, but also with those recorded in pertinent British and American publications. The coincidence has been good in the interval where the single rain attenuation distribution value is greater than 0.01%. The estimation method, described in this article, has sufficient accuracy for practical use.

This article describes about the PNPN diode-transistor switching circuit with automatic turn-off mechanism, and the pulse voltage level discriminator fabricated as its application.

It is well known that networks containing both lumped and distributed elements can be treated by the theory of mpr's (multi-variable positive real functions). In the theories of cascade synthesis so far developed for those mixed networks, it has been emphasized that the value of network functions depend only on one variable at any transmission zero. So that, the component sections were composed of J-element (Jun-element) pi and its I-element (Inverse-element) pi1. However, a certain class of multi-variable transfer functions does generally have transmission zeros depending on a set of several variables. In the present paper, the separation of the sections which produce transmission zeros depending on two variables, are discussed. In the result, the separation of the four reactance sections are discussed. These four sections correspond to A (or B), Richards, Brune and Hazony-Youla sections for one-variable case.