Abstract
With the progress of society and the development of technology, people’s living standards and requirements have gradually increased, and their requirments for the performance and the cost-effective of various products have become increasingly high. Therefore only those products that can meet the living needs of consumers can be accepted.
HGT2212/HGT2222 broadcasting recorder is the pre-launch audio resource and the central controlling equipment of the emergency broadcasting system. The background music of HGT2212 is played by tape and the background music of HGT2222 is played by CD or MP3, both of them have an interface with the linkage device. The recorder uses the solid-state electronic recording mode for broadcasting and recording incidents. On the principles of ensuring a normal performance in case of emergency as well as focusing on ordinary broadcastings, this series of products are added a number of practical features, namely nice bell-sound entry, background incremental volume control and so on. Among them the most characteristic one is-- with two sets of power amplifiers this series of products can make an emergent broadcasting and a backgroud broadcasting at the same time, so that not only the command mission of evacuation in incident region can be achieved, but also a tranquil and peaceful atmosphere in non-accident areas can be mantained.
Through the development process of this project, this thesis studies and designs the man-machine interface circuits for various processes such as inputting, displaying and so on in a CD recorder. In this way, the functions of operating and monitoring can be achieved through the user interface of the CD player. Besides, the protel99SE software is used to draw and make the schematic and PCB board of the device.
