A fast algorithm for computing the maximum number of prime implicants of n-variable symmetric Boolean function is described. A dynamic programming technique is used in the algorithm. The total logarithmic computing time cost and the total uniform computing time cost by a random access machine are O (n⁴) and O (n³), respectively. The algorithm can be implemented faster by a parallel computer. The corresponding computing time costs by a parallel computer with O (n) processors are O (n³) and O (n²), respectively.

The source coding problems are studied on the Slepian-Wolf-type system with a remote source (Fig. 1) and the Wyner-Ziv-type system with a remote source (Fig. 4). For the former, inner and outer bounds are obtained on the admissible rate region to attain a prescribed distortion tolerance. For the latter, the rate-distortion function is derived. As examples, a Gaussian remote source and a binary remote source are analyzed.

A model for analysis of life test data on typical electronic components is presented. Since viewpoint and manner for analysis of life test data is not established for humidity accelerated life tests, some life-time characteristics under humid environments are mainly considered in order to illustrate utility and applicability of the proposed model. Obtained results indicate that the model makes up possible to interpret some different models proposed by some researchers on the humidity accelerated life tests from a consistent manner connecting the life-time characteristic of components with fundamental nature of failure mechanism of each component. The model will allow to us to understand each of data obtained from some types of life tests on various electronic components as an essential part connected with whole information on life characteristic of the components under various use and environmental conditions.

A synthesis of high frequency active RC filters using an operational amplifier with single pole characteristics is presented. As a measure of the quality of filters, the pole sensitivity with respect to the gain bandwidth product GB of the amplifier is used and it is shown that the absolute value of the pole sensitivity has a minimum limit. The synthesis is based on the predistortions of Q and center frequency errors caused by the finite GB of the amplifier. The proposed circuit has quite stable temperature characteristics and examples show illustrative differences of the temperature responses between the proposed circuit and conventional ones.

In order to find the optimum index profile of the single-mode optical fiber with respect to the cabling loss due to the random bends with the Gaussian correlation function, the relation between the random-bend loss and the index profile is investigated. The formula of the random-bend loss is derived for arbitrary index profile. In the derivation, the loss is calculated as the power of dipole radiation due to the equivalent refractive index perturbation in contrast with the conventional mode coupling analysis. Using this formula, random-bend losses are calculated for four types of index profiles; the convex, parabolic, step, and concave type of index profiles, under the condition that connection losses are same for all types of profiles. As results of the comparison, the random-bend loss is minimum in the case of the convex type of profile and it is decreased down to 40% of that in the case of the step profile.

Sintering process of porous performs made by a vapor-phase axial deposition (VAD) method has been investigated. SEM observation indicates that the final stage of sintering is the collapsing process of closed pores in the transparent glass body. A bubble-free transparent perform is easily obtained by sintering in the helium gas atmosphere, but hard in the argon gas atmosphere under the usual zone-sintering condition. An interpretation of the experimental results is presented based on the elementary model for final stage of the sintering process; the closed pore collapsing depends on the balance between gas permeation rate into the surrounding glass and pore expansion rate during temperature increase.

Recent progress in the theory of nonlinear waves" has clarified that various nonlinear dispersive soliton transmission equations can be transformed into certain types of bilinear equations. In this paper, a general form of bilinear soliton transmission equations which have a form of simultaneous equations for two dependent variables is presented. Then, a method is presented for constructing their generalized soliton solutions, which are solutions expressing solitons in a background o ripples. As a result, it turns out that if these bilinear soliton transmission equations have N-soliton solutions, they also have the generalized soliton solutions. Moreover, taking the modified Korteweg-de Vries equation as typical example of the soliton transmission equations which are treated in this paper, it is also shown that its initial value problem can be solved using its generalized soliton solution. Since the results for the modified Korteweg-de Vries equation can be easily extended to all soliton transmission equations which can be transformed into a certain type of coupled bilinear equations and whose N-soliton solutions can be written by determinants, it also turns out that transmission characteristics of a wide class of nonlinear dispersive transmission equations reducible to coupled bilinear equations can be clarified by making use of their generalized soliton solutions. A simple application of these results to a design problem of soliton transmission lines is also noted.

Partial response is applied to an optical fiber transmission system with low fiber loss for the purpose of expanding repeater spacing beyond the range imposed by fiber bandwidth restriction. Detailed theoretical and experimental results on the relation between receiver power penalty and data rate to fiber bandwidth ratio are presented. Duobinary codes are preferable to non-return to zero full response codes, provided that the 3 dB fiber bandwidth is less than 0.6 times the data rate.

Gyrotropic thin-film waveguides with isotropic top layers are discussed using hybrid modes. The fundamental propagation properties of optical waves and TE-TM mode conversion efficiencies are estimated. When refractive indices of isotropic top layers are equal to those of substrates, 50% TE-TM mode conversion efficiency required for non-reciprocal circuits of optical isolators can be realized with gyrotropic films. From a fabricational point of view, these structures are very useful for constructing thin-film optical isolators because no severe control on film thickness is necessary and film growth of amorphous materials on YIG crystal films is possible for top layers. The design data for non-reciprocal circuits consisting of ZnO/YIG/GGG layered structure are presented from the hybrid mode analysis. The thickness of YIG and ZnO are 3.43 µm and 1.03 µm respectively and the length of the device is 2.28 mm. The non-reciprocal circuits of this structure can be experimentally fabricated by RF sputtering method.

This paper describes measurements of fiber loss and splice loss by backward Rayleigh scattering in fibers. Fiber loss measuring accuracy less than0.04 dB is obtained, and the repeatability is very good in comparison with conventional cut-back method. For splice loss measurement, the measuring accuracy is the same as the above. It is found that the splice loss measured by the backscatter method is different from the true value for fibers with different Rayleigh-scattering losses. To obtain the true value, several correction method for the measured value are proposed. Application of the backscatter method to fault location reveals that even an 8.6 km distant fiber end-face without Fresnel reflection can be discriminated.

We have proposed a new SAW amplifier oscillator which has an acoustoelectric SAW amplifier and an electric feedback loop, and realized the CW oscillator experimentally. The theoretical study of the SAW oscillator has been done using the saturation characteristics of the SAW amplifier.

A new single-fiber bidirectional wavelength-division-multiplexing transmission system is proposed, which employs LEDs with the same wavelength. The feasibility of this system has been confirmed by a transmission experiment.

Simple design curves are presented for linear phase, low-pass impedance matching networks. A parallel RC and an RLC load are considered. Using the design curves, we can easily determine the maximum DC gain K for a given load.

One parameter family of solutions of the second Painlevé equation, which describes long time asymptotic behavior of waves in certain soliton transmission lines, are constructed through its bilinear form. It is then shown that the derived solutions have the Painlevé characteristic, i.e., they have no movable critical points.