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With a view to accurate and fast time domain analysis of nonuniform transmission lines, a method is presented for applying the FDTD method to a finite length nonuniform transmission line. A step response analysis is carried out for a parabolic line as one of the nonuniform transmission lines. Effectiveness of this approach is confirmed by comparison with analytical solutions and other methods. An equation for the voltage at the initial rising duration of the step response of a nonuniform transmission line is derived. It is shown that if the nonuniform transmission line has the characteristic impedance with a continuous distribution the initial arriving voltage can be determined by the characteristic impedance at both ends of the transmission line. As an application, a method is described for approximating the step response waveform of a parabolic line to a step wave. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 85(2): 22–31, 2002 [ABSTRACT FROM AUTHOR]

Y-type and Z-type parabolic-taper single-mode transmission lines and their equivalent circuits are first discussed. Then, by superposition of two of the above single modes, the TEM mode along a parabolic-taper coupled transmission line (PTCTL) is analyzed. According to the choice of Y-type or Z-type for tapered single modes and the choice of combinations of balanced-unbalanced modes or open-short line modes as two independent superposed modes. there can be six types of PTCTL. Their equivalent circuits are also easily shown. Through the superposition of the voltages and currents of two Y-type single-mode parabolic-taper lines, a Y-type parabolic-taper coupled two-wire line is obtained. Similarly, from two Z-type single-mode parabolic-taper lines, a Z-type parabolic-taper coupled two-wire line is obtained. Furthermore, from a Y-type parabolic-taper line and a Z-type parabolic-taper line, we derive a mixed type of parabolic-taper coupled two-wire line. In any case there are two forms of combinaction, balanced-unbalanced modes and short-open line modes as superposition of two independent modes. An obtained nonuniform coupled two-wire line dogs not always have the same taper. A special case of interest is that in which one of the two wires of a coupled line has decreasing taper and the other has increasing taper. Finally, a low-pass filter is designed by the use of nonuniform coupled transmission lines and it is shown that the line length along the axis can be reduced. [ABSTRACT FROM AUTHOR]

This paper discussed the measure of information for the event using the probability theory by Dempster and Shefer. By providing various kinds of information to the event containing an ambiguitym the ambiguity us gradually decreased to define the event in a clearer way. The combination rule by Dempster is most suited to represent the combinations cab be made for Dempster's combination rule. Then using the upper and lower probabilities defined by the basic probability of the event, the upper and lower information measures are defined, followed by the discussion of their properties. The lower probability of a set (event) us defined as the sum of basic probabilities of all subsets in the set, and the upper probability is defined as the sum of basic probability is defined as the sum of probabilities of all sets which contain an element of the set. Thus, the upper and lower information measures can be interpreted as the measures of information concerning the message with ambiguity. Finally, several examples are discussed, determining the information measure for the message containing ambiguity. [ABSTRACT FROM AUTHOR]