It is well-known that electromagnetic (EM) disturbances in vehicle-mounted radios are mainly caused by conducted noise currents flowing through wiring-harnesses from vehicle-mounted printed circuit boards (PCBs) with common ground patterns with slits. To evaluate the noise current outflows from the PCBs of this kind, we previously measured noise current outflows from four types of simple three-layer PCBs having two perpendicular signal traces and different ground patterns with/without slits, and showed that slits on a ground pattern allow conducted noise currents to flow out from PCBs, while the levels for the symmetric slits ground type are smaller compared to the case for two asymmetric slits ground types. In the present study, to further investigate the above finding, we fabricated six types of simple two-layer PCBs having two parallel signal traces and different ground patterns with/without slits, and measured the cross-talk noise between the traces. As a result, we found that the ground patterns with the slits perpendicular to the traces increase the cross-talk noise levels, which are larger by 19-42 dB than those for the ground pattern with no slits, while the ground patterns with the slits in parallel with the traces can suppress the noise levels, which are slightly smaller by 2.5-4.5 dB compared to the case for the no-slit ground pattern. These results were confirmed by the FDTD simulation, and were also qualitatively explained from an equivalent bridge circuit model we previously proposed.

抄録全体を表示

Influences of a co-axial measuring cable have been neglected in the lightning impulse measurements. This is partly because an allowable uncertainty for determining the front-time, T₁, in the reference measuring system is 3% and the induced influence by using a long measuring cable is expected to be much smaller than the margin. The authors have so far suspected the validity of this argument through experience. This paper proposes analytical treatment of impulse response at the end of a lossy cable. Using the proposed expression, measured parameter errors are compared to the numerically evaluated ones and it is to be confirmed that both are in good agreement.

抄録全体を表示

We previously developed an optical sampling oscilloscope (EDT-OSO) based on an envelope detection triggering method. This EDT-OSO can stably measure eye-diagram waveforms of signals exceeding 100Gbps without an external high-frequency clock signal. However far-end waveform measurements during a long distance place could not be realized. Because the EDT-OSO requires to link 10-MHz time bases in the EDT-OSO and a light under test (LUT) generator for synchrinizing.
To overcom this drawbak, we developed a direct bit-rate measureing method for synchronizing both 10-MHz time bases vartually and a self-synchronized EDT-OSO (SSEDT-OSO) based on this method simulteniously. We confirmed that a bit-rate measurement repetability of the SSEDT-OSO was from 10^-9 to 10^-8 by evaluating a standard deviation and the SSEDT-OSO could measure an eye-diagram without linking 10-MHz time bases.
This paper explains the basic principle for measuring the bit-rate of the LUT directly. Furthermore, we describe a configuration of the SSEDT-OSO and evalluation results.

抄録全体を表示

Relationship between barrier discharge characteristics and ozone generation under ac voltage application on triple needles-plane configuration has been investigated for various distances among triple needle-tips (d=0 ∼ 7.0mm) at constant distance between needle tip and plane (g=3.0mm) in dry air. Characteristics of barrier discharge and ozone generation depend on the needle-tips distance. It is considered that the influence is caused by space charge and accumulated charge suggested from discharge image by still camera and CCD camera. And ozone generation efficiency is also estimated by power consumption and ozone concentration. As a result, when the distance among triple needle-tips is narrow, the above-mentioned influence is strengthened. And in this case, ozone generation efficiency is improved.

抄録全体を表示

The progress of integrated-circuits technology in recent years has enabled a large performance-increase of system LSI. As it is needed long time to study the knowledge of the system LSI such as design, semiconductor process, and estimation of device, it is hard to study system LSI technology for company man and students. The basic consecutive system consisted of design, process and estimation of a fundamental IC system was studied.

抄録全体を表示

The influence of electrode thickness on ozone generation in the electrostatic precipitator(ESP) was experimentally investigated. The experimental ESP was two-stage-type which composed of a prechager, followed by the collecting section. The precharger consists of high voltage electrodes and grounded electrodes. The thickness of high voltage electrode was selected as 0.1, 0.2, 0.5 and 0.8 mm and the grounded electrodes was 1.0mm. The collecting electrode section had parallel-plates configuration. The gases emitted from the diesel engine were diluted with air and introduced into ESP in order to measure the particle counts were attributed to saw type electrode. In the present study, the electric field distribution was caluculated using the commercial coad called “Ansys”. The relationship between the ozone generation and collection efficiency was investigated. As a result, the ozone concentration decreased with decreasing the electrode thickness maintaining the same collection efficiency. This result is attributed to decreasing the dissociation area of O₂ in the vicinity of the electrodes.

抄録全体を表示