全数字可视对讲终端的设计与实现

he Digital Video Intercom System, with acquiring and transferring voice and images as its core function, is gradually replacing the Analog Video Intercom System as the standard requirement of a residential community today. A video intercom terminal which can reduce the cost as well as the complexity of such a system is introduced in this paper. By employing a multimedia SOC Z228 which contains a multi-media processing unit MPEG-4 codec and a control unit known as ARM core as its central unit, the terminal also has many peripheral interfaces and controllers often used, such as the LCD controller, the camera Sensor interface and the audio data bus interface.The experiment result shows that the terminal can acquire the video data and then code or decode it according to the MPEG-4 standard within a single chip and it can be used to communicate visually at a speed of 30 frames per second under the resolution of 640 times 480 via VGA. In addition to handling the digitization problem effectively, the terminal can improve the quality of images and reduce the complexity of the whole system; therefore, it can be widely in occasions which need a visible inter-conversation such as residential communities, hospitals and video conferences.