1. Research and development group Hitachi, Ltd. and Kanazawa University,Hitachi,Japan
2. Research and development group Hitachi, Ltd.,Kokubunji,Japan
3. Research and development group Hitachi, Ltd.,Hitachi,Japan
4. Daido University,Department of Electrical and Electronic Engineering,Nagoya,Japan
5. Kanazawa University,Faculty of Electrical, Information and Communication Engineering,Kanazawa,Japan