Professional Audio Data Acquisition System Based On Ethernet

The development of modern science and technology centered on informationtechnology,the people, things and things closely were linked by information technology,andinformation technology of the three is based on: information collection, informationtransmission, information processing, corresponded sensing technology, communications andcomputer technology.Data collection and transmission are significant in variety ofintelligent devices. But a large amount of real-time data collection, transmission is more hotand difficult tnan before,these noise, accuracy, delay, bandwidth requirements are higher.In the audio field, signal digitization, networking become the current directiondevelopment,However, development of Ethernet-based digital audio network technology hasregarded as the professional audio industry technology highlights.Audio signals digitally is tosolve noise interference in analog audio signal transmission or processing, but also solve theanalog system is difficult to achieve the volume of the monitoring.Audio signal networktransmission can break through sound audio signal the geographical limits, of an audio signalsystem management.And the consumption of the streaming media technology, professional audio networktransmission of the real-time requirement is very high, allowing the transmission delay mustbe controlled within a few milliseconds. In order to meet the real-time requirement, must thesampled digital signal for direct transmission, reducing the compression technology bringcompression, decompression and the degradation of sound quality in compression process.Inorder to obtain high quality voice data, and ensure the sound signal of low distortion, highquality output, usually requires high precision conversion device. When using48kHzsampling rate,24bit coding, a stereo PCM digital audio flow high amounts to2.2Mbps,real-time transmission must solve audio flow and system channel between capacity.This topic is in the ARM to build a WinCE platform to achieve the Ethernetcommunication. The use of S3C2440powerful control ability and rich interface resources tobuild friendly user interface to Ethernet PCM audio code transmission and control. Collectingport to24bit high ADC progress to2times over sampling, to ensure that the original signallow error recovery;10M/100M adaptive network support large data volume low delaytransmission; incidental D/A ports also with high precision conversion device, increasing the dynamic range, reduces to the analog output of the filtering requirements.The system is based on S3C2440core board and A/D, D/A, net export is composed ofthree parts. A/D interface chip with the CS5396, OP275and OPA2134in construction of thefront stage circuit is also made front end security; D/A part contains PCM1704, OPA627,OPA2134builds digital-analog conversion and after low-pass filtering; networkcommunication interface is used for high speed adaptive16bit parallel transmissionDM9000A. Terminal software is in WinCE5.0SDK developed by VC++applications, inPlatform Builder5do the corresponding driving modification. Terminal software through netport communicates with PC through the terminal software, and the Windows modified versionand WinCE double platform verification.