This paper describes designing on required signal to crosstalk power ratio of symmetrical cable for bipolar pulse transmission. Error rate in bipolar pulse transmission is discussed taking into account average signal to far-end crosstalk power ratio, average signal to near-end crosstalk power ratio and their standard deviation. Experiments were conducted with regard to the relation among average signal to crosstalk power ratio, its standard deviation and error rate. Calculated and measured results show good agreements. From these results, designing on required signal to crosstalk power ratio and its standard deviation in dB for required error rate is clarified.

This paper describes an analytical investigation of mode-coupled graded index (GI) fibers. The analysis is based on the Scattering Matrix Method. The mode coupling parameters of the fibers are clarified in calculations and experiments, and the results obtained are used to determine the actual transmission characteristics of long, spliced GI fibers, for the wavelength region near 1.3 µm, as well as for the region near 0.85 µm. It is determined that coupling between adjacent modes is dominant and that a microbending loss of an order of about 0.1 dB/km results in an extremely large increase in the bandwidth of GI fibers larger than 20 km. In this paper the propagation constant for mode groups with the same propagation angle is derived directly from a WKB analysis.

The authors have previously reported the algorithm of a lowpass-type variable cosine equalizer in the case of relatively rough input data. As a continuation of this work, in this paper we will propose a new algorithm applicable to the bandpass-type input data.

The m-center problem asks to place m objects on the plane so that the distance from a client (a point) to the closest object is at most a given number r. This problem is often encountered in locating facilities or resources of a geographically distributed system. This paper shows that this problem is NP-complete. The NP-complenteness indicates its computational intractability, i.e., it is most unlikely that some algorithm can solve it in polynomial time of the problem size.

In this paper, a partial matching problem among pictures composed of multiple closed regions is described by taking a sequence of animation pictures as an example. Closed regions including holes and islands are analyzed and described by a set of edges specified by angles, positions, trailing and leading vectors. Then, a kind of relaxation methods is used to make partial matchings between the preceding picture (template) and the current picture through global and local matching processings. This method was applied to a sequence of cel animation pictures drawn manually, and as the results, more than half of closed regions included in pictures were identified correctly.

Dependence of GaAs power MESFET performance on the device parameters was experimentally investigated. Power gain and output power were most sensitive to the gate length, giving the degradation rates due to increase of the gate length of 1.7 dB/µm for the power gain and 0.67 dB/µm for the output power. The effect of the gate finger width on the microwave performance was not serious and the performance deterioration at 8 GHz did not begin until the gate finger width of 200 µm. Temperature dependence of the microwave performance of GaAs power MESFET, as well as the dependence of the thermal resistance on the device geometric parameters, was investigated quantitatively. Power gain degraded with increase of the device temperature with the rate of 0.026 dB/.

This paper describes an optical demultiplexer whose diffracted light beams are directly detected by a monolithic linear array of six silicon pin photo-diodes for the 0.8 µm wavelength region. The demultiplexer has 6 channels whose wavelength spacing is 23 nm. Insertion losses and crosstalks were less than 2.1 dB and -25 dB, respectively.

This paper shows an experimental approach to the understanding system of natural language and pictorial patterns. The system is titles as ISOBAR (an Information understanding System Of BAsic weather Report). It can accept both linguistic and pictorial inputs. Also it produces either linguistic or pictorial, or both, output according to the commands which it received. The most remarkable point of the system is that the performance of the system is based on the semantic processing of the input. As ISOBAR's world is limited within the weather report of Japan and Far East Asian areas with associated weather charts, so the semantic background of the system is very narrow, and is quite a specific one. But the methodologies and algorithms in the system will be the first step for the embodiment of the more complicated and more general systems. ISOBAR has two operating modes in principle. One is the accumulation of meteorological information, and the other is its retrieval. According to the experimental outcomes, the performance of the system is almost good except for the picture processing procedures. Finally, the problems for the future research are remarked.

A left identity type automation is defined as a finite automation whose transformation semigroup has a left identity. In this paper, we give a necessary and sufficient condition for a given automaton to be of left identity type in terms of the generators of its transformation semigroup.

To study material dispersion effects on transmission characteristics in optical fibers, material dispersion properties in GeO2-P2O5-doped silica optical fibers were determined as a function of GeO2 doping concentration. The material dispersion properties were evaluated from pulse delay measurement with nanosecond pulses in a 0.60-1.65 µm spectral region generated by a nanosecond optical pulse radiator. From the measured delay, refractive index of core glass, material group index, material dispersion, zero-material-dispersion wavelength and zero-dispersion wavelength in a single mode fiber have been determined as a function of GeO2 doping concentration in the range 4.1 to 19.2 mol %. By extrapolating present data in GeO2-P2O5-SiO2 ternaries, material dispersion properties in fused GeO2 glass have been predicted. The zero-material-dispersion wavelength in fused GeO2 glass can be estimated to be 1.68 0.03 µm.

It is shown that we can simultaneously make both of Zech's logarithm table and trace table in a finite field by using a feedback shift register which generates a pseudo-random sequence. Convenient method for the initial loading of the feedback shift register is given.

A Josephson computer device called a carousel SQUID is proposed which uses an interferometer capable to be used as both a memory cell and logic gate. The principle of the operation of carousel SQUIDs is the rotation of a fluxoid quantum in the device, which makes the device to have excellent performances as computer ones. The memory cell stores one fluxoid quantum and is non-destructive read-out one. For the logic gate, the current gain is much larger than unity and input signal is isolated from the logic gate.

This correspondence is concerned with finding a set of pels for the prediction of NTSC signal when we are restricted to using a finite number of pels. The forward selection procedure and other methods are discussed, when they are applied to the intrafield prediction of the television signal.

Requirements for a telecommunications network are becoming diversified in accordance with progress in social activities. To meet flexibly variable requirements, the telecommunications network should be provided with high capability exchange systems. For such a purpose, the stored program controlled (SPC) switching system may play a key role. In order to process calls in the telecommunications network environment, a signaling system is inevitable. In the telecommunications network, composed of electronic switching systems, the interoffice signaling system should be efficient when handled by a stored program. This paper describes modeling of interoffice signal processing and formulates parameters evaluating signal processing effectiveness. As a numerical example, multifrequency (MF) and common channel (CC) signal processings for a 9 digit transit call in a toll originating switching system served by D-10, N.T.T.'s commercial switching system, are analyzed in an assumed environment of the present analog and the future digital telecommunications network. From the result of this analysis, the paper concludes that a common channel signaling system is effective in the present analog network from the SPC viewpoint. If a digital environment is assumed in the future, a multifrequency-like individual channel signaling system is considered to be effective due to the improvements in dialed number transfer, inherent easy channel state recognition and no necessity for a continuity test. It is also suggested based on the interoffice signal processing analysis to use a common channel signaling system as an interoffice data link between switching offices and a data base, where data on routing (selected speechpath link) or subscriber are stored.

The effect of relative refractive index differences of single-mode fibers on zero-dispersion wavelength was investigated. Optimizing the fiber parameters, a single-mode fiber has been realized, which has minimum loss and minimum dispersion at the same wavelength in the 1.5 µm region.

A polarization-independent optical circulator for optical fiber communications is presented. It consists of a YIG Faraday rotator, a quartz half-wave plate and two pairs of rutile prisms. Insertion losses are 2.3 dB and isolations are 33 dB with fiber connection.

Static characteristics of InGaAsP/InP double-hetero-structure laser diodes with stripe geometry have been examined. Relation between stripe width and "kink power", Pk, where a kink appears in the light output vs. current curve, is demonstrated experimentally. It is shown that a 7 µm-wide stripe laser diode exhibits the stable fundamental transverse mode oscillation as well as the single longitudinal mode oscillation. Growth rate of TM mode is found to be remarkably reduced after TE mode oscillates in the 7 µm-wide stripe mode stabilized laser. The dependence of threshold current, Ith, on the stripe width is examined experimentally and Ith is found to increase when the stripe width is decreased to less than about 10 µm. By taking mode loss into consideration, the increase in Ith with narrowing the stripe width is explained.

This paper proposes a method for calculating transfer function of transmission lines composed of combinations of multimode fibers with arbitrary index profiles. Bandwidths of graded-index fiber transmission lines are estimated taking into account optical equalization, mode conversion and deviation of index profiles from the power-law. Optical equalization greatly improves bandwidths for power-law fibers. As for those which deviate from power-law profile, perturbation of index profiles with low transversal spatial frequency significantly decreases the bandwidth of graded-index fibers. It is important to eliminate the low spatial frequency perturbation in index profiles to provide fibers with wide transmission bandwidths. Bandwidths of transmission lines are estimated when the phase of sinusoidal perturbation in the index profile varies randomly between the fibers at the sending and receiving ends. Calculations suggest that a 100 MHz bandwidth can be expected at a fiber length of 100 km, when deviation from the power-law profile is controlled to within 0.5% of relative index difference between the on-axis and cladding.

This paper considers a two-unit warm standby redundant system. Preventive maintenance (PM) for an active unit is scheduled after a certain period. When an active unit fails or undergoes PM while the other is in standby, the operation is switched to the standby unit. Probability of success in switchover is constant. If the system fails in switchover, the system stops the operation, and resumes it after a certain time. MTTFF, MTBF and steady state availability are obtained. Numerical examples show the effects of PM interval on them.

A new CCD linear image sensor with 2,048 elements has been developed by introducing photodiode processed by selective oxidation and ion implantation technologies. This construction provides high quantum efficiency at visible light with smooth spectral response, an output non-uniformity of1.5% and a dark current saturation time of 20 s. A transfer efficiency of 99.999% is achieved from a two-phase buried channel CCD. Transfer loss mechanism at a transfer gate was examined and the minimum aperture time of the gate proved to be as low as 1 µs. Spatial resolution of the device is superior to conventional sensors because of sharp sensitivity profile of the photoelement.