[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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Characteristics of modified batwing antennas (MBA) have been analyzed theoretically using the moment method and the results compared with actual measurements.
A 2-element MBA was designed having octave band characteristics, that is, when the reflector and radiator are in 1 : 1.2 ratio, element space 15m and VSWR is below 2.0. Gain of the 2-element MBA was calculated to be from 4.0 to 6.5dB in a 300 to 650MHz range. A wide band for impedance and gain was attained.
Calculated results were compared with measured values to demonstrate the accuracy of the analytic method. As a result, it was found that the calculated and the measured values agreed well, and satisfactory wide band characteristics were obtained.
Finally, it was concluded that it would be possible using these results to improve the charecteristics of a UHF-TV receiving antenna.

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This paper presents a design method for a vector quantizer based on absolute value distortion measure for the purpose of high-efficiency video coding. It quantizes normalized video signals block by block in the multi-dimensional signal space. Besides, a fast vector quantizer for real-time operation and an interframe DPCM combined with the fast vector quantizer are presented. Their high-efficiency coding performances are demonstrated through computer simulation and concrete design methods are described. The set of output vectors for vector quantization is generated through the clustering of actual video signals. The vector quantizers reproduce superior images at a low bit rate.

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