Voice Communications Systems Based On Can Bus

Since the field bus development, CAN bus is one of the most promising technologies. Numerous scientists and technicians is paying more attention to this field bus now.It is important to establish a voice communication system in order to supervise the control condition,such as industrial field, traffic, electric power system. In most applications,the voice communication is based on the traditional circuit switch and the PSTN.Since the development and maturation of the field bus,CAN bus was more widely used then before.And it shows its powerful advantages to us.This paper introduces a hardware circuit design of a voice communication system based CAN bus,dicussing the applications of transmitting real time voice. The paper mainly discourses upon the software/hardware design of a voice communication through CAN bus.The system consists of two important component,one is the Motorola's MC14LC5480 which working as audio sampling and codec,the other is AT89C55 as MCU.This system is tend to transmit voice signals among several nodes by CAN bus,which works in the PELICAN mode.In the first half of this paper,it present voice coding technology and CAN bus communication network.It also estimates the advantage of the voice signal over CAN bus,analyses the performance of Motorola's single channel PCM codec filter--MC14C5480,discuss the sampling rate of the voice system.The second half of this paper discuss the software/hardware technologies of the voice communication system which based on CAN bus.This paper also analyses each correlative function module in the system, include voice codec circuit,digital signal process circuit and CAN bus transmit circuit.