Although limit values for the radio disturbance (EMI) of information technology equipment (ITE) have been given in the revised recommendation of CISPR 22 (1993), they give a difference in the order of 10 to 20 dB, depending on the mounting height of ITE, measurement distance and polarization. For example it is almost impossible to find a correlation between "3-m method : semi-anechoic chamber (with a metallic floor)" and "10-m method ; CISPR type open free site". This can be settled easily through defining the radio disturbance limit within a free space and using a free space type site (opened or perfect anechoic chamber). The EMS test, the EMI measurement in 1 GHz or higher, etc. have so far presupposed the use of the free space type site and therefore revision of the specifications presently used is indispensable to insure consistency with them. This paper explains that an error in converting the radio disturbance limits in CISPR 22 (1993) is attributed to an error in technical basis of the FCC OST 55 (1982) and it has been used without correction.

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Stochastic analysis of error correcting and detecting codes for intermittent faults is made and the result is evaluated by comparing the simulation data. The single parity code, single error correcting code, and single error correcting and double error detecting code are evaluated by their effective code rates introduced in this paper for combining the ordinary code rate and their reliability.

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In Satellite communication systems for direct connection to subscribers, a radio terminal is required to have stable operation in low C/N and short synchronous acquistion time. This report presents a new clock recovery circuit with moving average filters, which satisfies the above requirments. Concretely, the operation algorithm of this circuit is analytically explained. Then, various performances, such as operation stability in low C/N, acquistion time and recovered clock phase error caused by sampling frequency, are clarified by using a computer simulation method.

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As a simple communication method for mobiles and others, Code-Sensing Communication System (COSCOS) has been proposed. The fundamental concept of COSCOS is applying the idea of bar-code reader system to a simple communication system. This paper describes that COSCOS using a magnetic sensor is available method for a mobile communication through both an analysis and experiments using a car.

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The coupling response of an external transient electromagnetic field to a transmission line is considered. To verify the line equations for a transmission line excited externally by a transient near-field, the experiment is conducted ; the model field is generated by a monopole antenna supplied with a step-like source, which is installed in the vicinity of the transmission line. The waveform of the step-like voltage source is decomposed of the discrete spectrum components by using the technique of Fourer transform. The frequency-domain field-components affecting the transmission line are estimated by using the moment method, and then the induced voltage in the frequency domain at the terminal load is converted into the time domain voltage by using a technique of the inverse Fourier transform. Comparison between the measured and the computed results shows the verification of the line equations. Moreover, the coupling mechanism is discussed from the experimental results ; the response seems to consist of components received at both line terminals, where the affecting fields are those from the bottom and the top of the mouopole antenna, and in addition them, the multi-reflected for the non-matched line.

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An automatic mesh generating program for 3-D FD-TD electromagnetic field analysis is investigated. This program consists of 1) defining the objects on the X-window by using the primitives, 2) dividing the objects into variable finite-difference cells, 3) defining the material constants and boundary conditions and 4) applying the boundary conditions. Variable meshes are useful in order to reduce the computing time and memory while maintaining the accuracy, however, descretization errors may occur. A method is proposed to reduce the error. Finally, a reentrant resonant cavity applicator for cancer therapy is divided automatically into variable meshes by using the program.

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