Research And Design Of Multi-channel Audio Stream Mixing Equipment Based On Embedded Linux System

In the21st century, the rapid development of embedded technology, embeddedsystems based on electronic products have been widely used in people’s daily life, wherethe audio device in people’s lives is to become an indispensable component. Audioequipment performance improved audio technology development is inseparable from thecurrent pace of development of digital audio technology is quite amazing, and in the mostcommonly used digital audio technology, the most important thing is multi-channel audiomixer audio technology. Mixing technology is often used in communications, multimediaclassrooms, performances and other occasions, these occasions for real-time audio mixingrequirements are very high, so how real-time multi-channel audio signal mixing digitalaudio technology is always difficult and hot research.The new mixing equipment is mainly used for the synthesis of a variety of percussionsounds and opera performances as a background sound, the basic idea is to advance thesound of various musical instruments made of WAV files on behalf of a button on thekeyboard of a music file that is the sound of a musical instrument, through the controlbuttons to control the sound of different instruments playing simultaneously pressingmultiple keys if you use software synthesizer and multi-channel audio streams real-timeplayback, so you can hear a variety of musical instruments at the same time sound isequivalent to more than one person playing.Therefore, research of this subject is toachieve complete a band controlled by a percussion synthesizer task. Thus the number ofpeople with less complete in the past a lot of people need to work together to complete thetask, significant savings in manpower.The core of this thesis is based on the embedded Linux environment, to achievemulti-channel audio stream mixing equipment, the system completes the keyboard inputaudio stream, mixing multiple audio streams and real-time playback. In this paper, bothhardware and software aspects, clearly outlines the development process for embeddedmixing equipment and design principles. Using S3C6410processor, WM9713audiocodec chip, ZLG7290B keyboard control chip hardware platform.This paper analyzes theaudio mixing algorithm and a sound card and keyboard interface and driver architecture.The main work is as follows:(1)Hardware design. Design Audio keyboard input and output circuits, the workingprocess research and keyboard control chip processor interface IIC and the audio codecchip with processor interface AC97’s working process.(2)Development environment to build and drive design. Build a system developmentenvironment, mixing equipment system transplant embedded Linux operating system inmulti-channel audio stream mixing device device driver design, as well as preparemakefile, dynamically loaded into the kernel driver module. (3)Software Design related software to achieve multi-channel audio mixing functions.In software design, the use of the clamp mixing algorithm will mix multi-channel audiostreams and clamp.Through access to large amounts of data, build a good mix of hardware structure ofthe device, the software algorithm to achieve a mix of multi-channel audio streams, todesign a mixing device.