In this paper, we briefly introduced the performance of wave coding and vocoder, emphasizedly studied the principle and performance of variable rate vocoder q4401, including the internal construction and pins, qcelp coder & vocoder, pcm interface, cpu interface initialization process, command format and so on . we also designed a application circuit, with the experiment validated its performance . in this design, the pcm interface chip is tp3057, it was used to finish a / d transform, the compress coding was finished by q4401, the initialization and control were accomplished by 8051 singlechip 重点是研究变速率语音编解码芯片q4401的工作原理及性能。其中包括q4401的内部结构及管脚、qcelp编码方式、pcm接口、cpu接口、初始化过程、命令格式等,并在此基础上,设计一个实际的应用电路,通过实验,验证其性能。在设计中用pcm接口芯片tp3057来完成从模拟信号到数字信号的转换,再由q4401进行压缩编码,对q4401的初始化及控制由8051单片机来完成。
Ip voice gateway is a node between the communication control unit and the server of trunking system in trunking system network . its duty is digital compress coding and packetization of the voice in trunking system . it located on the edge of the network and accessed the trunking system into ip network from the kernel network angle 语音网关作为集群通信系统ip联网的关键设备,它处于集群系统话路控制单元和集群系统服务器之间,起着语音压缩、分组传输的重要作用;从网络的角度来看,它处于ip网络和集群无线通信系统之间,把集群通信系统接入ip网络。
This thesis introduces in details the design and functional realization of the models of video compression, decompression and video transport . after this, some key relating technologies, including com, directshow, windows socket, tcp / ip, video compress codes and transport technologies, have also been presented in the thesis to realize a complete digital video monitoring system 本文对系统中视频压缩、解压缩,视频数据传输等模块的设计方法及功能实现都进行了比较详细的介绍。本文还简要介绍了设计实现该系统所用到的各种相关的关键技术:包括com技术与directshow技术、视频图像压缩、传输技术以及相关的网络传输协议tcpip、windowssocket技术。实现了一个完整的数字视频监控系统。