Research on The Spread Spectrum Communication Systems.

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From April 1988 to March 1990 , study meetings have been held for eight times major results of the studies are summarized as follows.To increase the information transmission capacity is one of most important problems in the present day Spread Spectrum (abbr. SS in the following) systems. Various study works have been conducted in this field.G.Marubayashi & S.Tachikawa ( Nagaoka Univ. of Technology ) showed a possibility of improving transmission capacity by adopting Mary SS system. M.Hatori ( Univ.of Tokyo ) & N.Suehiro (Tokyo Engineering Univ.) proposed an efficient SSMA ( Spread Spectrum Multiple Access ) system using polyphase orthogonal sequence. Y.Tanada (Kagoshima Univ.) proposed an efficient SSMA system using real number orthogonal sequence. T.Hasegawa (Saitama Univ.) proposed a synchronous SSMA system using chip shift method.To find new application fields for the SS systems is also an important problem in the present state. Several research works have been conducted in this field.G.Marubayashi & S.Tachikawa studied applications for the electrical power line data transmission. M.Nakagawa (Keio Univ.) showed a possibility of application to the data carrier system. Y.Miyazaki (Toyohashi Univ.of Technology) investigated an application to the optical communication system.Applications to the consumer communication systems using weak radio wave are investigated by several research workers.Various novel circuit and system design techniques have been proposed. H.Imai & R.Kohno ( Yokohama National Univ.) showed a possibility of high speed synchronous acquisition system using generalized Geffe sequence. T.Hasegawa proposed an improved DLL circuit using the manchester code. S.Mori ( Keio Univ.) proposed an efficient high speed frequency synthesizer.Through these research works , future possibilities of the Spread Spectrum Systems seems to have enhanced greatly.