In recent years along with electronic technology's development, specially corresponded the profession development, presented various means of communication, the line-wire communication, wireless communication each one has presented many kinds of different ways. This in ours daily life everywhere obviously. But present correspondence's infrastructure equipment has certain limit expensively regarding some specialized application domain. For example uses in the hospital hospital ward ringing system, the dining room intelligence orders food the system, the workshop emergency call system and so on, if these equipment's research and development use our present stage existing medium to carry on the transmission, is not only advantageous in saves the cost moreover to develop is also quite simple. present aims at these demands, the people started the power line carrier communication research. In order to cater to the market demand and seek for the more appropriate development program. In ours this subsystem design, we proposed the electric power line number obviously hospital ward ringing system's development. This system including carrier encode circuit, carrier transmission electric circuit, receive decoding circuit three parts of constitutions. Through develops this system equipment, not only may enable us to have the profound understanding to the power line carrier communication, and has certain guidance function in the research and development function more perfect power line carrier system aspect.
key word： power line carrier; Hospital ward call; Encode circuit; Receive decoding circuit
