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 重點是研究變速率語音編解碼芯片q4401的工作原理及性能。其中包括q4401的內(nèi)部結(jié)構(gòu)及管腳、qcelp編碼方式、pcm接口、cpu接口、初始化過程、命令格式等,并在此基礎(chǔ)上,設(shè)計一個實際的應(yīng)用電路,通過實驗,驗證其性能。在設(shè)計中用pcm接口芯片tp3057來完成從模擬信號到數(shù)字信號的轉(zhuǎn)換,再由q4401進行壓縮編碼,對q4401的初始化及控制由8051單片機來完成。
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 語音網(wǎng)關(guān)作為集群通信系統(tǒng)ip聯(lián)網(wǎng)的關(guān)鍵設(shè)備,它處于集群系統(tǒng)話路控制單元和集群系統(tǒng)服務(wù)器之間,起著語音壓縮、分組傳輸?shù)闹匾饔?從網(wǎng)絡(luò)的角度來看,它處于ip網(wǎng)絡(luò)和集群無線通信系統(tǒng)之間,把集群通信系統(tǒng)接入ip網(wǎng)絡(luò)。
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 本文對系統(tǒng)中視頻壓縮、解壓縮,視頻數(shù)據(jù)傳輸?shù)饶K的設(shè)計方法及功能實現(xiàn)都進行了比較詳細的介紹。本文還簡要介紹了設(shè)計實現(xiàn)該系統(tǒng)所用到的各種相關(guān)的關(guān)鍵技術(shù):包括com技術(shù)與directshow技術(shù)、視頻圖像壓縮、傳輸技術(shù)以及相關(guān)的網(wǎng)絡(luò)傳輸協(xié)議tcpip、windowssocket技術(shù)。實現(xiàn)了一個完整的數(shù)字視頻監(jiān)控系統(tǒng)。