摘要
本课题中研究和实现了基于以太网技术的音频传输单元，基于以太网技术的音频传输单元的功能是利用廉价普及的以太网实时传输多路高质量音频信号。该设备可以通过一根普通5类线实时传输多达16路24bit、48kHz未压缩音频信号，并允许音频数据与标准以太网数据包共存。网络音频信号的输入输出可以自由选择、切换和路由，具有相当大的灵活性和高性价比，克服了复杂的音频工程方面模拟系统的局限性，简化了网络设计、安装和设备的管理，满足了专业音频传输、分配系统数字化、网络化需求。传统的音频系统中，音频轨道都要与一条音频电缆相连；多房间、长距离安装复杂；音频内容的管理和监控都需要附加硬件设备和电缆；音频路由需要人工接线或昂贵的音频传输单元，系统的重新配置也是复杂而耗时的过程。基于以太网技术的音频传输单元可以利用5类线同时传输音频和控制数据；音频设备可以通过以太网独立监控；音频数据可以传输到单个或多个目的地；音频路由可以通过更改地址信息轻易地完成。本文的重点是介绍基于以太网技术的音频传输单元中FPGA模块逻辑设计和实现，以及AES数字音频I／O模块原理图及PCB设计和实现。项目中采用Xilinx公司集成开发环境ISE4.2作为开发工具，进行了HDL代码编写、功能仿真、综合、布局布线及可编成BIT文件生成等。最后，将可编程BIT文件转换为第三方支持mCS文件格式。FPGA模块实现功能：音频选路、正弦波产生、ADC定标控制、LED显示控制等。同时，利用单片机实现了FPGA配置程序加载。本文还对系统进行了测试，包括AES数字I／O模块调试、FPGA逻辑功能调试及系统联调。通过测试，基于以太网技术的音频传输单元完全达到了设计要求。基于以太网技术的音频传输单元完全符合AES／EBU硬件规范，满足专业音频传输、路由需求。最后，本文还重点介绍了以太网控制器的FPGA设计与实现。首先介绍了以太网的基本原理，然后介绍了以太网控制器程序的主要结构和主要功能模块的实现，并对以太网控制器的功能进行了验证。验证结果表明，利用FPGA实现的以太网控制器满足设计要求。本人在项目中完成的主要工作：与项目组成员合作完成系统方案设计及FPGA器件选型工作FPGA程序(RTL，Testbench)编写同步FIFO设计与实现FPGA配置的MCU实现以太网控制器FPGA程序的顶层架构设计及各个模块实现AES数字I／O模块原理图及PCB设计系统调试及产品实现
This subject is mainly to introduce the design and implementation of an audio unit based on ethernet. Up to 16 channels' audio can be transmitted in real-time through this unit,uncompressed audio is with 24 bit's resolution and its sample frequency is 48 khz in one CAT-5 cable. Audio data can co-exist with standard ethernet packages.Besides,network audio can be freely selected、swithed and routed over the network.Because of its huge flexibility and high performance, this audio unit overcomes the shortcomings of analog audio network such as complex audio installation,and simplifies audio network design,installation and management of devices,which meets the requirements of professional audio's digital transmission and distribution through network.
In the past's audio system there're some shortcomings.Firstly,audio channel is connected with an audio cable;Secondly,the installation in multi-room or long distance environment is complex;Thirdly,extra hardwares and cables are needed in the management and monitoring of audio data;Lastly,audio routing is manually operated or by expensive audio routers,also,audio system's reconfiguration is complicated and time-consuming.In comparison with the past's audio system, audio and control data can co-exist in CAT-5 cable through this audio unit;The audio units can be separatedly monitored over ethernet;And audio can be transmitted to one place or many places;Audio routing can be easily finished by modifying addresses.
Two parts are included in the thesis: the design and implementation of FPGA module and AES digital audio I/O module. Xilinx Corporation's ISE4.2 is used as development platform to carry on FPGA design,including HDL coding,functional simulation,logic synthesis,place & route and generation of programming files.FPGA is used to implement audio select,sine wave,ADC's calibration and LED etc,.Also, the configuration program is downloaded into FPGA chipset by MCU.Eventually,the unit is tested and the requirements of design is met properly.
Also, the design and implementation of MAC is demonstrated with emphasis,including the principle and main architecture of MAC.Besides,most submodules are introduced.The verification of MAC shows that MAC meets the design requirements.
As followed is my major work:
The system's architecture design and selection of FPGA chipset
FPGA (RTL, Testbench)coding
Synchronous FIFO design and implementation
Configuration of FPGA chipset with MCU
The design and implementation of Top-level module and submodule of MAC
The design of AES I/O module
The test and implementation of this device
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