1. INTRODUCTION

There have been many investigations of mutual synchronization and multimode oscillation in coupled oscillators [1] –[4]. In [1], Endo et al. have reported the multimode oscillations in various types of the coupled oscillators networks. In [2] –[4], the synchronization phenomena in resistively coupled oscillators have been reported. In particular, we have reported synchronization phenomena observed from oscillators with the same natural frequency mutually coupled by one resistor [3], [4]. In these systems, various synchronization phenomena can be observed. Especially, in LC oscillators system, we have confirmed experimentally that -phase oscillation can be stably excited when each oscillator has strong nonlinearity [3]. In this case, there exist ! stable phase states according to the initial states. Moreover, we have investigated the coupled system with RC Wien-bridge oscillators. They also exhibits the “phase-shift synchronization” and we can get different stable phase patterns [4]. Because these “star-coupled” oscillators exhibit a large number of different steady states, they will be used as a structural element of large scale memories.