High speed optical system to measure the shape and the cross section of the three dimensional object was developed; this system consists mainly of a He-Ne laser, a polygon mirror, a PSD, a turn-table for rotation of the object, and a personal computer.

Design of ferrule hole diameters in a ferrule-type single mode fiber connector has been investigated to achieve a low-loss multi-fiber connection. Based on the theory of the connection loss statistics, connection losses for various designs of ferrule hole diameters are evaluated and discussed.

This letter describes design and performance of a multicore fiber connector with a plastic-molded ferrule. Discussing ferrule fabrication errors, the connector loss and crosstalk were evaluated. The constructed connector for joining and fanouting multimode two-core fibers showed an insertion loss of 0.4 dB and a crosstalk of less than 35 dB.

The needs for high-resolution full-color display are increasing very rapidly. The requirements which are necessitated for high-resolution full-color display are reviewed. CRTs are achieving almost all of these requirements but size and weight. Real flat displays having good cost and performance are expected in future.

Spectral properties of an unlocked semiconductor laser under an external light injection are numerically analyzed and experimentally observed. It is found that the unlocked spectrum consists of a shifted carrier and a number of harmonics and that their distributions are varied by the detuning.

A method for automatic detection of a critical point in voltage waveform in breaking contact arc has been developed. The point and a transition term from metallic to gaseous phase were detected by searching a peak in voltage fluctuation. Each phase differed in feature of corresponding waveform such as the gradient and the fluctuation.

Experimental studies were made of the transition from metallic to gaseous phase in Ag break arc in low air pressure (50-760 Torr). In the current range, in which the break arc burns only within the metallic phase, metallic phase duration is found to decrease with decreasing the air pressure.

Polarization fluctuation in optical fiber submarine cable coupling under periodic variable tensile force with 4-7 tons are presented. It is found that the polarization fluctuation of the optical fiber submarine cable coupling linearly changes with periodic variable tension.

The position-sensitive photovoltage is observed in a device construction composed of a Pb2CrO5 thin film and a pair of Au planar electrodes. An observed linear relation between the photovoltage and the light beam position might be useful for sensing the light beam position.

This letter is concerned with the investigation of electromagnetic wave scattering by an infinite patch grating. The analytical method used here is based on the spectral domain method combined with the sampling theorem. Numerical results are given for transmitted and reflected powers when frequency or polarization angle is changed.

An active circuit for detecting a small capacitance change accurately with a minimum number of components is presented for interfacing a capacitive sensor with a digital system. No component trimming is required and the sensitivity to circuit constants is minimum. Thus, it meets all the requirements for the on-chip interface.

This paper proposes a statistical expression of the output error variance due to coefficient quantization in separable denominator M-D digital filters. Using this expression, this paper shows that minimization of overall quantization errors can be performed by minimizing the roundoff noise.

This paper presents three types of prefiltering for FIR digital filters to decrease the number of multipliers required. The first type is based on cyclotomic polynomials. It can be applied to any types of band-selective filters. The second is a mirror-image quadratic polynomial to make a passband shaping. Both types of the prefilters are used with the interpolation technique, and this improves each primitive characteristic in terms of the sharp transition. In the prefilter-equalizer design approach, these prefilterings bring about the reduction of the number of multipliers required in hardware implementation. The prefiltering efficiency is demonstrated by a few examples.

A new self-aligned recessed-gate GaAs MESFET is developed using RIBE for recess etching. Recess-etching depth can be precisely controlled by RIBE with BCl3 etching gas. Barrier height and ideality factor of the Schottky contact formed on 200-V bias-voltage RIBE etched surface are 0.8 V and 1.2, respectively after 400 annealing. A very short gate-length is realized simply using the sidewall formation and the conventional photolithography. Furthermore, a self-alignment of ohmic electrodes and N+-layers to a gate electrode is realized to minimize the source resistance. The 0.3-µm gate-length MESFET fabricated on a wafer with the carrier concentration of 1.21018 cm-3 grown by MBE shows the transconductance as high as 415 mS/mm.

Let G be a directed graph containing n nodes and m edges, with each edge of nonnegative length. Given two specified nodes s and t, the length of a k-tuple of edge-disjoint paths from s to t in G is the sum of the lengths of all the edges on these k paths. A polynomial time algorithm for finding a shortest k-tuple of edge-disjoint paths from s to t in G has been devised. Based on this algorithm, this paper considers the problem of finding a second shortest k-tuple of edge-disjoint paths from s to t in G, for which an O (min[n3, nm log n])-time is described.

The system performance is greatly affected by the interprocessor communication, which should be enough to support the various types of permutations functions for the mapping purposes. But if there are many types of manipulations, it becomes necessary to have a rearrengeable IN like the Benes Interconnection Network (IN) so that we can increase the number of stages to 2n-1, where N=2n, and N is the number of input terminals which is base 2. But the control algorithm for this kind of IN is very complex. In this paper we have studied the mapping capabilities of Benes IN to be used into super system and we give a control algorithms for setting this network for groups of manipulation functions proved to be efficiently useful for parallel computation. We have also, shown how to enhance these control algorithm to be used by the system programmers with examples. Also, we have given cases studies for kinds of applications to be applicable in such system, so that to realize the effectiveness of such mechanism.

The performances of parametric receivers such as the linear, the maximum likelihood and the hard limiter have been analyzed before for the detection of frequency-hopped multilevel frequency-shift keyed signals (FH-MFSK) in mobile radiotelephony. Also, nonparametric receivers such as the maximum rank sum receiver (MRSR) and the reduced rank sum receiver (RRR) were previously considered. Here, a receiver called the mean level receiver (MLR) is analyzed. It is neither parametric nor nonparametric. It depends on the noise (or interference) distribution except for a scale parameter which may correspond to the noise power. The proposed receiver is distinguished by its easier implementation, constant false alarm rate and relatively good performance.

This paper discusses an efficient implementation of fault-tolerant digital filters based on the residue number system. In this implementation, a compact residue arithmetic module named the pulse-train residue arithmetic circuit" is effectively employed as the basic module, and an efficient error detection/correction algorithm in which error detections is performed in each basic module and error correction is performed based on the parallelism of residue arithmetic is also employed. Two design methods of fault-tolerant digital filters are newly proposed. In one method the error correcting circuit is imposed in series to the non-redundant system, and in the other the one is imposed in parallel. The prior has an advantage of compact hardware, and the latter has an advantage of high-speed operation. Following the proposed method, a 2nd-order recursive fault-tolerant digital filter with 3 digits is practically implemented, and its fault-tolerant ability is proved by noise injection testing. It is found that the hardware of our digital filter is 70% of the one based on the conventional tripple modular redundancy (TMR), and the mission time improving factor of our digital filter is 150% of the one of the TMR system.

The average coefficient sensitivity is defined for 2-D systems described by Roesser's local state space model. The sensitivity can be computed by using the 2-D observability Gramian and the 2-D controllability Gramian, which are also called the 2-D noise matrix and the 2-D covariance matrix if the 2-D systems are considered to be 2-D digital filters. Minimization of sensitivity via 2-D equivalent transforms is studied in cases of having no constraint and having a scaling constraint on the state vector. In the first case, the minimum sensitivity realizations are equivalent to the 2-D balanced realizations modulo a block orthogonal transform. In the second case, the 2-D systems are considered to be 2-D digital filters and the minimization of sensitivity is equivalent to the minimization of roundoff noise under l2-norm scaling constraint. An example is given to show method of analysing and minimizing the sensitivity of 2-D systems.

A study is presented on the generalization of the M/M/1 model with synchronous fluctuation of traffic intensity for the case of more than one server. The parameters of the queueing system fluctuates between two phases and the phase process is assumed to make changes according to an irreducible Markov chain. Phase changes may occur only when a customer arrives to the queue, further, his service time is also determined at his arrival instant. We compare our results to that of the asynchronous one and the comparison clearly shows that we can approximate the performance of the asynchronous model by that of the synchronous one and vice-versa. However, we point out that, to extend the M/M/K (M/M/) model with fluctuating parameters to the case of general interarrival, service, or sojourn time distribution, is easier in the case of the synchronous model than in the case of the asynchronous one since the latter introduces very considerable analytic complications. Two models, the M/M/K and M/M/, with synchronous fluctuation of parameters are analyzed in depth. Explicit results for the expected queue length are presented and discussed. Finally, numerical examples are used to support the theoretical analysis for a variety of traffic conditions.