Design Of Service Multiplexer In DMB Transmitter Baseband SoC

In emergency scenarios,Digital Multimedia Broadcasting(DMB),which is portable,low latency and highly stable,plays a vital role.In the current DMB broadcast system,the transmitter must be connected to a PC,resulting in a large transmitting system.At the same time,the system has a high delay in real-time voice broadcasting,which is not conducive to flexible use in emergency scenarios.To address the above problems,this thesis combines the DMB transmitter SoC project being developed in the laboratory with the on-chip processor in the SoC and uses embedded programming techniques to transplant the service multiplexing from the original PC into the SoC,while redesigning the real-time voice broadcast to improve the integration of the transmitter,reduce latency and enhance the emergency communication capability of DMB.The research elements of the thesis are:1.Improvement of the DMB transmitter front-end system architecture.Use the embedded processor in the SoC to transplant the service multiplexer from the PC to the transmitter baseband SoC.The SoC FPGA development board was used as a platform to implement the design of the service multiplexing system using embedded programming techniques.The designed system can receive STI data and multiplex it to synthesise ETI data.The above improvements allow the transmitter to multiplex programme data without relying on a PC,enhancing the level of integration.Meanwhile,a low latency voice broadcasting method based on DMB fast information channel is proposed for the demand of real-time voice broadcasting in emergency scenarios,with the theoretical latency reduced to 86?102ms to meet the transmission demand of real-time voice.2.Design of DMB network transmission communication system.The USB transmission between the transmitter and the client is changed to Ethernet transmission,and the DMB network transmission system based on TCP and UDP protocols is completed through socket network programming.The transmitter can receive programme data from the service component provider directly within the SoC chip via Ethernet,completing the service multiplexing.The above design allows the transmitter to work independently from the PC,reducing the size and cost of the overall transmitting system and promoting the flexible use of the transmitter in emergency scenarios.3.Design of concurrent transmission system for DMB services.In response to the multi-threaded and highly concurrent data transmission characteristics of the DMB transmission system,the Zero MQ framework is used to design the DMB service concurrent transmission system,including the message module,network communication module and client management module.The test results show that:(1)the service multiplexer can receive STI data and synthesize ETI data;(2)the average delay of each encoding frame is 2ms,and the synthesized data has good sound quality and normal BER after transmitting;(3)the system can carry out network transmission with Zero MQ via socket;(4)the CPU occupation rate is 1.6% when connecting one service component provider,and the concurrent transmission No less than 16 service component providers can be accommodated to meet the application requirements of DMB.