A holographic pattern measuring method which combines both techniques of holography and graphic image processing was developed. As a typical application, this method was applied for the analysis of thermal distortion of a printed circuit board (PCB) due to current flow through a point contact, and quantitative thermal distortion pattern of the PCB was obtained.

A quantitative observation of damage on the electrical contact surface is very difficult so far because of no proper measuring system. Therefore, developement of a new measuring system for this purpose is needed for performance estimation of characteristics of electrical contacts. A digital image signal processing technique was applied for this purpose and the experimental results show that the developed system is very useful for quantitative observation of contact surface.

A noninvasive method for measuring complex permittivity of biological tissues is proposed. The noninvasive method is based on an inverse scattering technique which employs an iterative procedure. The iterative procedure consists of solving an electric field integral equation using the method of moments and minimizing the square difference between calculated and measured scattered fields. Implementation of the noninvasive method requires the knowledge of the target shape, the incident and measured scattered fields. Based on the noninvasive method, a measuring system of complex permittivity is developed and its reliability is verified.

A principle of new Parallel Fourier Transform (PFT) system using a differential transform matrix (DTM) is presented, and its hardware implementation is carried out. The PFT is one of the methods which can execute real-time Discrete Fourier Transform with a low-cost parallel processing. In this paper, the derivation of PFT using DTM is mentioned from the original PFT using polyphase system. It is shown that the PFT using DTM can execute the DFT by 2.5N digital additions or subtractions (where N is the number of input signal points) for each Fourier component, and its hardware is shown. Finally a typical experiment of the PFT is presented.

We discussed on relationship between the width of slit ray and the accuracy of the measurement system for surface profile of electric contact. To obtain resolution of 10 [µm], we designed the mechanism which keeps constant the focal length between the object and the lens. As a result, the width of slit ray was clear in the whole surface. A section image could measured exactly and enhanced the resolution.

The effects of Gaussian electromagnetic noise and non-Gaussian one on TV picture degradation are studied by using a composite noise generator which can control noise parameters. Three kinds of still pictures and four kinds of motion pictures are tested, and the picture degradation is subjectively evaluated with five-grade impairment scale. The tendency of the picture degradation against the every picture is almost the same. But MOS (Mean Opinion Score) between still picture and motion picture degradation is different in some measure when the power of burst noise is small.

The accumulated metallic phase arc duration in Ag electrical contacts was log-proportional to the amount of electrode mass change, and the relationship was irrespective of the air pressure condition. It can be considered that the electrode mass change closely depends on the metallic phase arc.

In this paper, to clarify the thermal effect of the bridge for long lifetime contacts, the effects of heat conductivity on bridge break at different material contact pairs were discussed experimentally. To examine the relationship between the bridge and material, the electrode materials of the anode and the cathode were chosen as the same and the different material pairs in this experiment. Ag, AgPd60 and Pd were chosen as the electrode materials, because Ag, AgPd60 and Pd had the different thermal diffusivity. Firstly, the voltage waveforms in the bridge with different material pair were compared to the voltage waveform with the same material pair case. Secondary, the effects of heat conductivity on the break of bridge were discussed. In the results, the bridge voltage waveform depends on the electrode material at anode side. The length of the bridge at bridge break depends on the heat conductivity of the electrode material at anode side. This study provides the basic considerations on the thermal condition of the bridge break.

A cascode type AM modulator, which is the combination of a static induction transistor (SIT) and a JEFT is proposed. The experimental results show the improvement in linearity and distortion because of the good constant voltage characteristics of SIT.

In this paper, an argumental approach is introduced for an expression of correlation functions between two arbitrary codewords. The real parts of the correlation values are mapped onto the argument vector, then the components of the vector are plotted on a unit circle by each angle. The imaginary parts are expressed on the another unit circle by the same manner. The distinctive features of the proposed method are described in comparison with recent expression methods, and some examples of the application are demonstrated along with numerical results. The argumental expression is shown to be a generalized way to indicate correlation functions for all possible codewords.

For grasping the electromagnetic environment, the visualization as a pattern of electromagnetic field distribution is effective. Generally, the electromagnetic field distribution pattern is composed of several fields caused by different electromagnetic wave sources. In this paper, a method of pattern decomposition of overlapped electric field pattern is proposed. This method is based on the least square estimation of intensity of electromagnetic wave sources under the assumption that the location of every source has been given. The estimation formula of electric field intensity of sources is derived. This method is applied to decompose the real patterns measured in semi-anechoic chamber. These experimental results show that the method of pattern decomposition can be used to eliminate or extract the unwanted reflected and scattered field with less error.

A random pulse stream (RPS) generator was developed for the noise immunity test of various digital system including communication system. By using this RPS generator along with the composite noise generator (CNG) developed formerly, the Middleton's "Class A" noise could be generated, and the total system (RPS+CNG) became more general noise simulator. In this paper, the configuration of CNG with newly developed RPS generator, and a typical example of Class A noise generated by this system are shown.

Holographic pattern measuring system (HPMS) which has been developed by the authors as applied to measure a thermal deformation of contact spring due to current flow. As the results of investigations, a microscopical rolling of contact point was clarified and a relationship between the changing spring shape and the contact voltage was qualitatively mode clear.

Surface damage of the electrical contact is a primary cause of failure in many electronic devices which use sliding contacts. Therefore, the quantitative observation of the contact surface is one of the most important subjects for improvement of contact reliability. In this study, in order to clarify the relationship between the contact resistance and the damage on the contact surface, a digital image measuring system (DIMS) was developed. A shadow image processing technique (SIPT) was applied to the damage analysis on the sliding contact surface. The damage width on the contact surface and the damaged image could be obtained with a 3-D graphic image by applying both DIMS and SIPT. Part of the relationship between the damage on the contact surface and the contact resistance could be obtained in the case when Cu is used for the moving contact and Cu and Ni are used for the static contact.

A composite noise generator (CNG) is proposed for simulating the actual non-Gaussian noise and its applications are mentioned. Basing upon the actual measured result (APD) of induced noise from electric contact discharge arc, the APD is approximated by partial linearlization and shown that it can be simulated by a combination of plural Gaussian noise sources. Applying the CNG, quasi-peak (Q-P) detector is investigated and shown that the Q-P detector response is different for non-Gaussian noise when its time domain parameter is different even if its original APD is the same. For digital transmission error due to non-Gaussian noise, and for TV picture stained by the non-Gaussian noise, the CNG is applied to evaluate their performances and quality. The results obtained show that the CNG can be used as a standard non-Gaussian generator for several immunity tests for information equipments.

This letter deals with a newly developed automatic system, which measures the rate of malfunction of digital circuits owing to noise induced by breaking electric contacts. In this system, a personal computer is used for the detection and the count of the malfunction in the digital circuit. Its experimental results are reported here.

Reliability of an electric contact can be defined by two parameters, contact resistance and wear, and the parameters of contacts operated in arcing condition are governed by the arc discharge. Thus the measurement on the relationship between the parameters and arc phenomena is necessary to improve the contact performance. The parameters for arcing electric contacts and problems were reviewed, and new concept for electric contact testing systems was proposed. Measurement with such an advanced system should be concurrent parallel measurement, quantitative measurement of degradation, systematic measurement, and analysis of arc discharge phenomena. Some examples of advanced measurement systems and new data obtained with such systems were described. Systematic results on relationships between condition and performance parameters were obtained by systematic measurement with systematically settled conditions, such as opening speed or material condition. A measurement method for the metallic phase arc duration was developed by the authors, and role of the metallic phase arc on contact performance parameters was found from interpretation of obtained data. The real-time surface profile measurement of an operating contact and the optical transient spectrum analyser for arc light radiated from breaking contact were also described.

In this paper, a Micro-Step-Separating System is realized for investigating phenomena of initial state of separating contacts. This system can control the contact separation in a discrete way with about 0.5 µm step. By using this system, we observed a relationship between contact voltage and contact separation gap. Ag contacts were observed. The observation showed that the contact voltage rose up and then fell down to the stable voltage at each step separation. From this observation, we expect to elucidate the contact bridge phenomena with more sophisticated way because we can approach them under the thermal equilibrium condition.

The authors developed new measuring system (Holographic Pattern Measuring System [HPMS]), which is composed of both techniques of holography and graphic image processing, was used to measure the vibrations of a printed circuit board (PCB) due to operation of a mounted electromagnetic relay on it. The clear vibration patterns were obtained. By using pattern analysis processor, quantitative vibration patterns of the PCB surface were observed. Both the vibration patterns and displacements were changed by edge fixing way of the PCB.

It is necessary to know how the contact voltage and contact area vary with time to clarify the physics of contact lifetime and contact resistance. In this paper, to clarify the effect of the heating value on the diameter of the contact area, the variations of the contact voltage and contact diameter with time are measured at a low-speed breaking contact near the thermal equilibrium condition under which a stable bridge is generated. The effect of the heating value on the relationship between the contact diameter and the length of the bridge at breaking is also discussed. In the results, the contact voltage waveform was found to be macroscopically proportional to the displacement of the moving electrode lc. On the other hand, the contact diameter dc decreased slightly with increasing lc. At all currents investigated dc decreased when lc increased. The length of the bridge at breaking was increased by increasing the current. A large heating value of the contact area resulted in a long bridge because the volume of the melted metal increases.