As the basic study of the electromagnetic interference (EMI) problem at the circuit elements, the near magnetic field distributions above resistors for the termination of a transmission line are measured to reveal the profile of radiation. Five kinds of resistors and two types of resistance values are sampled. The results showed that the variation of the near magnetic field distribution above the transmission line is effected largely by the reactance of the resistor at the high frequency. These results are the basis for the design of the structure of the component.

Various approaches on optical network systems using wavelength-division multiplexing (WDM) technique have been proposed. It is difficult to make a scale of WDM network larger since a number of the optical wavelength which can be used is limited. In order to make easily larger scale of network, multi-hop WDM network have been proposed. We have studied 2-hop network: RookNet which has simple routing algorithm and high network throughput. Nodes in RookNet are divided into row groups and column groups and are placed in a mesh form. Packets are transferred between nodes over 1-hop or 2-hops. The 2-hop transfer means that a source node sends packets to a destination node via a relay node. When 2-hop traffic increases, relay processing time in a relay node is increasing. This is the reason that network throughput becomes low. To solve this problem is very important. In this paper, we show RookNet rearrangement algorithm which replaces location of node within group so as to decrease the 2-hop traffic and to maintain high network throughput. Proposed rearrangement algorithm can achieve improvement of 10 percent in terms of throughput. We also propose RookNet configuration which discriminates optical wavelength and subcarrier effectively in order to decrease the relay processing time.

The effect of the structure with difference on cross-section for the enlarged models that simulates signal transmission line (STL) in the magnetic head of HDD is discussed. The experimental results suggested that strip and shield structure are effective for suppression of EMI.

The spatial distribution of the electric field in the low to high frequency bands radiated from printed circuit board (PCB) should be estimated continuously from near to far field. The characteristic of the electric field distribution is analyzed by the FDTD-multiple analysis space (FDTD-MAS) method, which can analyze from near to far field continuously, and compared with measured results. Since the analyzed electric field distribution is good agreement with measured results, it is suggested that the continuous distribution for electric field from near to far field can be calculated by the FDTD-MAS method. The electric field at low frequency is larger than that at high frequency within 1 m.

In this paper, the separation of heat generation and heat transfer related to temperature rise of silver palladium contact was investigated experimentally in order to predict the temperature rise of contact by the use conditions such as voltage range between 25 to 40 V, current range between 3.2 to 5.0 A and silver palladium alloy (AgPd) materials. Firstly, relationship between temperature rise of contact and supply power was discussed. The effects of heat generation and heat transfer on temperature rise were separated and quantified by least squares method. Secondly, effects of durations and integral powers of bridge and arc on temperature rise were also discussed by changing supply power. Results show that the integral power of the bridge increases when supply power increases. As the supply power increases, integral power of arc also increases. The temperature rise is dominated by integral power of bridge. Remarkable difference of bridge duration can not be seen in the five materials (AgPd30, AgPd40, AgPd50, AgPd70 and Pd). The supply power is increased, arc duration gets longer. As weight percent of Pd content increases, the effect of supply power on arc duration becomes larger. Consequently, the integral power of arc increases. This study is a basic consideration to realize methods predicting temperature rise of contact.

EMI coupling paths in an electronic controller are investigated experimentally. Common-mode current measurements on the attached cable are used for diagnosing changes made to the EMI coupling path. Experiments that include shielding various portions of the PCB, and re-routing high-speed traces are conducted to characterize the coupling path. A means of identifying and characterizing EMI coupling paths in functioning hardware, and relating them to design features, is demonstrated.

Negative group delay characteristics can be used to improve signal-integrity performance such as equalizer for compensation of the group delay of transmission line (TL). This brief-paper newly attempts to propose a concept of the embedded Folded-Stepped Impedance Resonator (F-SIR) structure with open-stub resonator, for negative group delay and slope characteristics at high-frequency as well as low-insertion loss. The concept of the proposed TL is based on the combination of resonance and anti-resonance due to open-stub resonator in order to establish wideband negative group delay and negative slope characteristics. The proposed TL is fabricated on PCB, and then the concept is validated by measurement and simulation.

By the derivative expansion method we solved a certain perturbation problem which well represents the phase lock loop. We derived the equation which describes the dynamics of a slowly varying parameter E, where E can be regarded as the averaged energy of the system approximately.

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.

Common-mode (CM) current on a feed cable attached to printed circuit board (PCB), which is one of main source of undesired electromagnetic radiation problem, is investigated by experimental and finite-difference time-domain (FDTD) modeling. In this paper, frequency responses of CM current on PCB and feed cable are modeled and analyzed as an electromagnetic interference (EMI) antenna, which depends on the configuration of PCB with a wire cable. Several different configurations are prepared to demonstrate the effect of PCB dimension on resonance frequencies of CM current. In the results, EMI antenna in the frequency band around the first resonance frequency was comprised of the ground plane and cable. In order to explain the frequency response of CM current, two EMI antenna models are proposed and demonstrated. EMI antenna is comprised of the ground plane and cable, and the other EMI antenna is comprised of the trace on the ground plane. It is suggested that the result is one of basic consideration for the ground plane with cable that have high EMI problem and resonance frequency of CM current.

Arc discharge at breaking electrical contact is considered as a main source of not only degradation of the electrical property but also an undesired electromagnetic (EM) noise. In order to clarify the effect of holder temperature on the bridge and arc-duration, opening-waveforms at slowly separating silver-tin dioxide contact with different holder temperature are measured and discussed experimentally in this paper. Firstly, as opening-waveforms, the contact voltage, the contact current and the movement of moving contact related to the gap length are measured simultaneously. Secondly, the relationship between temperature of the holder and duration of the arc was quantified experimentally. It was revealed that as the initial temperature of the holder becomes higher, arc-duration becomes slightly longer. More importantly, the holder temperature dependencies of percentage of each-phase (metallic and gaseous-phases) are different with different closed-current.

We investigated the relationship between the film characteristics and the sputtering rate of the MgO protecting layer in AC-PDP. As possible elements for determining the sputtering rate, we considered the density, orientation, and surface morphology. With respect to the orientation, we found that the sputtering rate increased for the sequence of (200) < (220) < (111). However, we noticed that orientation and surface structure are not really decisive factors affecting the sputtering rate; the density of the film is most important.

The circuit switching device by the electrical contact needs the high reliability and long lifetime. The very important factor for the high reliability, long lifetime and electromagnetic noise of the electrical contact is to suppress the duration and electromagnetic noise of arc discharge. Usually, the suppression of arc duration method is applying the external magnetic field. But, this method was not able to suppress the metallic arc duration and increased the voltage fluctuation at arc duration. Therefore, the new method for suppressing the duration and noise for electrical contact is expected. In this paper, a new method for suppressing duration and EM noise of arc discharge by applying housing pressure is proposed. To investigate the availability of proposed method, the measurement and some considerations on arc duration, voltage-fluctuation and current noise up to GHz frequency band generated by breaking contact in the applied pressure relay housing are reported. Firstly, voltage waveform and duration of the arc are measured. The effects of the pressure in the relay housing on the duration of the metallic and gaseous phase arcs are discussed. Secondary, voltage fluctuation, the spectrogram of contact voltage and current noise up to GHz frequency band are discussed. In the results, the proposed method with applying pressure makes shorter both durations of metallic and gaseous phases. The shorter duration of metallic phase is an advantage of the proposed method beyond the applying external magnetic field. As the housing pressure is increase, the voltage fluctuation and current noise becomes smalls. The proposed method can suppress the voltage fluctuation as well as arc duration. Consequently, the proposed method is on of the good solution to suppress the duration and electromagnetic noise of the arc discharge from electrical contact and result of this study indicates the basic considerations necessary to ensure good lifetime and EMC designs for electrical contacts.

Basic left hand mode transmission line (LH mode TL) characteristics made on PCB is an important future issue for the application of the EMC field. In this paper, possibility of a LH mode TL characteristic made by a folded-stepped impedance resonator (F-SIR) type is investigated experimentally and numerically. The experimental and calculated from FEM and equivalent circuit results indicate that some backward propagation characteristic and negative group delay can be established by F-SIR structure.

In this paper, a method of separating the effects of the thermal diffusivity, durations and integral powers of the bridge and arc on the temperature rise of AgPd contacts was proposed. First, the effects of the Pd content on the durations and integral powers of the bridge and arc, and the temperature rise of the contacts were discussed. Because the integral power of bridge was larger than that of the arc under our experimental conditions of 40 V open-circuit, 5 A close-circuit and 100 µm/s opening velocity, the temperature rise of the contacts was dominated by the bridge. No remarked difference in bridge duration can be seen among the six materials. Although the integral power of the bridge in the case of Pd was maximum, the maximum temperature rise of the contact was observed in the case of AgPd60. To clarify the contribution of each factor, the effect of thermal diffusivity on the temperature rise of the contact was evaluated by the finite-difference time-domain (FDTD) method. In the case of Pd, because its thermal diffusivity was largest, heat diffused rapidly. On the other hand, the thermal diffusivity in the case of AgPd60 was small, and heat diffused slowly to the holders. The maximum temperature rise was observed in the case of AgPd60. It was demonstrated that the proposed method of separating the effects of thermal diffusivity, durations and integral powers of the bridge and arc on the temperature rise of contacts is effective in enabling us to understand contact phenomena.

We have recently developed a programmable composite noise generator (P-CNG) which can easily control noise parameters such as average power, time-based amplitude probability distribution (APD), crossing rate distribution, occurrence frequency distribution and burst duration. Two applications of the P-CNG are demonstrated to show its usefulness. For the first application, Middleton's Class A noise is simulated. A method of setting parameters for Class A noise is demonstrated. The APD of P-CNG output is in good agreement with that of true Class A noise. In the second application, the P-CNG is used for subjective evaluation test (opinion test) of TV picture degradation. Five simple composite noise models with two kinds of APD are used. Other parameters such as average power are kept constant. Experimental results show that the envelope and APD of composite noises do not greatly influence the subjective evaluation. Finally the capabilities of the P-CNG are shown.

To clarify the mechanism of the generation of electromagnetic (EM) noise, current and radiation noise up to the GHz band generated by slowly breaking silver-compound contacts were investigated experimentally. The current and radiation noise at the GHz band were observed. It was demonstrated that the frequency spectrums of the current and radiation noise correspond to the frequency responses of the circuit admittance and radiation efficiency of the experimental setup, respectively. It was revealed that even if current noise at the GHz band is very small, it can cause a large EM radiation noise because of the high radiation efficiency. From the time-frequency domain characteristics of current noise, it was clarified that the peaks of current noise at 10 MHz band arise immediately after the initiation of the arc discharge and the transition from metallic phase to gaseous phase. On the other hand, the peak current noise above 100 MHz arises immediately after the initiation of the arc discharge.

The effect of a grounded conductive sheet placed over a PCB with a microstrip line on the electromagnetic noise shielding is discussed experimentally and with FDTD modeling. The grounding position of the sheet, which is connected with the ground plane of PCB, is changed. In results, the resonance frequency is shifted by the grounding position, and reducing the resonance of the input impedance should make a more effective shielding for EM noise radiation below 1 GHz.

The mechanism of dark bridge formed with very slow contact separating speed was empirically shown with some discussions from the experimental results which the authors have obtained by using the cantilever system for controlling contact gap. By analyzing the obtained results, we will assume some concept of formation mechanism of dark bridge. Since the thermal effect is inevitable in the bridge formation, this will be inferred from two points; one is the a-spot change at initial state of bridge forming, and another one is the thermal expansion due to bridge current that affects the shape of bridge. This paper will show from these two points the conceptual bridge formation mechanism in case of non-melting state of contact bridge which is called here dark bridge.

Induced noises from breaking contact arc discharge and sliding contact discharge of dc motor are measured by pick up coil and current probe. Statistical properties, amplitude distribution probability (APD), of induced noise waveform are analyzed by simple method using intermediate frequency of spectrum analyzer. It is shown that APD characteristics can be used to estimate statistical characteristics and peak value of induced noise. Simulation model of the noise made by the combination of Gaussian noise is mentioned. The model called the composite noise generator (CNG) can be good fit to the real characteristics of both noises from breaking arc and dc motor. Applications of the CNG for noise filter using toroidal coil shows that the CNG is useful to realize the test of noise suppression characteristics. What parameters of the CNG should be considered is described for further applications.