There are generally used the CIS PR's standard method to measure suppression characteristics of the filters. Even if their results are superion, actual action may by wrong. Proposed method measure the impedances and phase angles of filter from input and output terminals, and calculate the deterionation facters from them. This method can be measured the suppression characteristics of filter in all condition including worst case.
The characteristic curves of the noise filters in city can be classified into two types, namely one is sharped turned and another dull. The freguency band of sharped turned type's phase angle is very narrow which means easy to turned with source or load impedance and lose suppression function. Then we can judged the quality of filter by measuring phase angle characteristics.
The movement and structure of mid-latitude sporadic E layers are investigated using the HF Doppler technique. The three typical types of Doppler shifts are observed with the appearance of sporadic E, and the Doppler shifts expected from various types of moving sporadic E clouds are simulated using a microcomputer. The relative f_OE_S maps over Japan are described by processing the ionogram. Comparative study of their results is presented.
Under recent development of roadside radio (HAR) system, (1) new inductive cables have been studied. We already proposed, in our previous articles, (2)(3)(4) coaxial delay line type inductive cable having divergent electro-magnetic fields and this type cable was installed experimentally in our national route No.17. In continuation of this study, we are investigating here, several problems on inductive radio communication cable ; specially the characteristics of (1) symmetric type delay line and its fields end effect around cable terminal, (2) distributed coupled type coaxial cable and its loss increase are discussed. (HAR system, roadside radio, new inductive cable.)
Permittivity and permeability of short metal fibers-filled absorbing materials are investigated. Brass fibers from 1 to 4mm length with the diameter of about 60μm are used. The short metal fibers which are randomly dispersed into the absorbing material given an affect of variation in permittivity of the material. As a result of the experiment, permittivity was shown to vary with an amount of fibers, the length of fibers and frequency, while the permeability was not affected any change by the fibers.
Quasi-impulse responses of coupled linear dipole antennas are measured by use of a very short pulse for excitation. These antennas have nearly the same lengths. Further, a simple formula of the impulse response is derived using the transmission line approximation. As a result, it is suggested that tips and feed-points of each antenna have significant role in the electromagnetic coupling.
A numerical method to analyze the transmission lines under the influence of external electromagnetic field is presented. Steady state analysis is carried out by the alternating theory and transient analysis is carried out by the numerical inversion of the Laplace transform. The basic equation of the transmission line is expressed by the state equation and its solution is determined by given terminal conditions. This method can be applied to not only single transmission line but also complicated transmission nerwork.
The distribution of electric field around a human model was measured by an optical technique with a view toward the evaluation of field exposure on a human body. Using the object with a simple shape, the accuracy of the measurement was confirmed through the comparison with the numerical calculation, the usage of a conducting model is justified in the measurements using the real animal bodies with and without a conducting surface. The field distribution were obtained with a human model in different conditions, such as in-various postures and in grounded/insulated cases.
The biological effects of Rf irradiation at 2.45 GHz in microwave oven have been studied using the adults of Drosophila virilis. Two to twelve days old flies were irradiated for 10 or 15 seconds, then mated with the untreated flies. The lifespan of female flies was noted, and the teratological damages of flies which emerged from each test groups were observed. The teratoid flies come out from most of test groups. The lifespan of female adults and teratological damages showed a partcularlly difference between irradiated and control groups.
Immunity of electromagnetic interference about industrial computers is increasingly important as being used for various purposes. Conducted noise of electromagnetic interference is until now carried countermeasure into effect and estimated quantitatively. This time, we take notice of radiated noise and estimate immunity of radiate electric field about our industrial computer conform to MIL STD 461A/462. We confirm that our industrial computer is in conformity with class B of JEIDA 29. IMMUNITY NOISE INDUSTRIAL COMPUTER