  High communication speed and sufficient energy supply are the directions of
technological development. Energy and information available anywhere and
anytime has always been people's good wishes. On this basis, resonant beam
system (RBS) has demonstrated its unique superiority in meeting the needs for
energy and communication. The previous work has mostly focused on the analysis
of charging performance of RBS and its steady-state characteristics. In order
to analyze the communication performance of RBS more thoroughly, we propose a
resonant beam charging and communication (RBCC) system and use the equivalent
circuit analysis method to conduct transient analysis on it. The equivalent
circuit reveals the dynamic establishment process of the resonant beam from
scratch, which facilitates the analysis of the relaxation oscillation process
and a deeper understanding of the energy transmission and communication
performance. In addition, we explore the energy transmission and communication
performance of the RBCC under different energy allocation strategies.
