Research And Realization Of SHDSL Protocol Voice And Data Synchronous Tranmission Equipment Based On PowerPC

Nowadays, a great deal of wide frequency application, such as Internet access, DSL wideband access, long distance LAN access, video conference, workgroup data sharing, long distance communications, lots of data video service and so on, promotes the development of high speed net access requirement.Currently, most equipment can only provide asymmetrical data link to access to DSL. At the same time it can not trasmite data to long distance and the bandwith have no guarantee.For a large number of middle and small size commercial users, providing two-way symmetrical long distance transmission equipment is of great significance. In2001,ITU bring forward the SHDSL Protoco,it can solve this problem in the future.After research of quantities of materials, the voice and data synchronous transmission system based on SHDSL Protocol is put forward in this thesis. This system adopts the PowerPC series processors of Freescale corporation and the stable VxWorks operation system is inserted into it. Two links of telephone voice signal are compressed and combined into one link of voice data through AC48802 and FPGA which blends with two links of serial port data and is transmitted to GS2237 clip by HDLC Protocol to realize two-way symmetrical SHDSL Protocol. The longest transmitted distance of the two links of voice and two links of data can be over 10 kilometers, the largest bandwidth 2M/bps, and the least bandwidth 192k/bps. The first chapter of this thesis introduces theories related with data and voice synchronous transmission system, including SHDSL Protocol, VxWorks operationsystem, HDLC Protocol used for data transmission and some conceptions associated with telephone.Chapter two probes into hardware system design, including the design of processor's board and motherboard.Processor board is the focus of the whole designation, which connects the signal line with the motherboard by the linker to control the whole hardware circuit and to exchange data.The motherboard is the basis of the entire system. The voice part, the serial port and DSL part are all on it. The voice compressed by DSP chip and the serial port data from a link of signal through allocation, which is transmitted to the DSL part to realize data transmission.Chapter three focuses on software system designation. C language and programming based on operation are used under Tornado2.2. The system is composed of many tasks, and system resources are allocated to the tasks according to priority, interruption and signal quantity. All the tasks are carried out reasonably to realize data transmission.Finally, the author draws the circuit schematic diagram and the PCB according to the designation, and finishes the actual circuit board, which has been successfully debugged. After continuous tests, system function achieves the expected requirement.