The microwave scattering from periodical waves on water surface is analyzed with a model of sinusoidal water-wave and experiments. By X-band experiments in a periodical water-wave tank, it is shown that the intensity of the first order scattering varies in the manners of a sinc function of the water wave-number and of Bessel functions of the wave height.

In this paper, from the viewpoint of wave optics, a computational method is proposed for the loss analysis of multimode fiber splice due to such multiple misalignment as end separation, axis displacement and angular misalignment.

The propagation characteristics of nonlinear TE waves guided by dielectric optical waveguides which consist of media with intensity-dependent refractive-index are investigated. Numerical results for guiding property of nonlinear waves are presented.

This paper describes measured results of details of arc voltage fluctuations and a surge in breaking Ag contacts.

We show that symmetric Boolean fanout-free functions or cascade functions realizable by networks of AND's, OR's and inverters are only the functions 0, 1, x₁x₂x_n, x₁+x₂+x_n, _12n, ₁+₂++_n (n1). If we add exclusive OR gates as the elements of the networks, only the functions x₁x₂x_n and x₁x₂x_n+1 are realizable in addition to the above functions.

A new loop antenna system is proposed to detect the magnetic field of the natural electromagnetic wave in space in a very wide frequency band from 0.1 to 100 kHz. A single small loop antenna is followed by a network consisting of two transformers in series, one of which is optimized to pick up the signals at lower frequencies and the other, the signals at higher frequencies. Detailed analyses of the network are performed and the optimized parameters both on the loop and network are deduced for a small loop with an area of 0.50.5 m². The theoretically obtained pick-up factor and the threshold levels for minimum detection in each frequency band are confirmed through the laboratory experiments and the field observations of the natural VLF waves such as the whistler as well as the transmitted carrier signals from the VLF and MF stations. The system proposed has a potential merit when applied to the space experiment where the payload is limited. The work in this paper gives the fundamental for the design of the loop antenna system onboard the Japanese satellite (EXOS-D) to be launched in 1989.

This paper describes the refined analysis of the angle-tracking performance of a coherent amplitude-comparison monopulse radar system in the presence of an interfering second target and, on the basis of the results, proposes a new improved system. The original system investigated by Kliger & Olenberger deteriorates the tracking performance for the wideband AGC in combination with narrowband PLL case. By appropriately combining systems with and without PLL, our new system is shown to have good tracking performance for all bandwidth" of the AGC and PLL relative to the Doppler separation.

This paper gives methods for computing a delta file of two two-dimensional arrays of characters which we call character planes. A delta file is a description of the difference between two text files. Our methods compute the largest matching of two character planes in a tow-dimensional manner, and consequently give the minimum modification from one text file to the other using deletion and insertion characters in a two-dimensional way. Our first method computes the largest matching of two character planes based on the tabulation of a recurrence relation of matchings of character planes. Our second method computes the largest matching of two character planes based on divide-and-conquer of character planes. Our third method computes the largest matching of two character planes based on dynamic programming on trees. Those methods are natural extensions of longest common subsequence algorithms. As an application of our methods, viewing a tree-structured text file produced by a structure editor as a character plane, we can extract natural common portions of two tree-structured text files in a two-dimensional manner.

A so-called pipeline FFT achieves parallel processing among the stages, and its very high-performance and relatively simple control mechanism make it an extremely useful architecture for high-speed applications. Processing rate of the pipeline FFT processor, however, depends on the processing speed of a computation element of each stage, since the pipeline FFT architecture achieves an amount of parallelism only equal to log_r N or the number of stages. Two important FFT architectures are described in this paper. The first architecture achieves a great amount of parallelism compared with the conventional pipeline FFT. Based on the constant-geometry pipeline FFT, the algorithm is extended to the multi-pipeline constant-geometry FFT of an arbitrary number of pipes. This architecture also realizes homogeneous structure and a simple control mechanism compared with the conventional pipeline FFT architecture. The second architecture described allows contiguous data blocks to be processed continuously by only a single set of FIFO buffers instead of a double buffering and switching mechanism. By this modified multi-pipeline constant-geometry FFT architecture, overall system efficiency can reach 100% by only using a single set of buffers for each stage even though an architecture based on the not-in-place algorithm.