Design Of Navigated Car Radio System Based On Control Of Single Chip Microcomputer

The development of automotive industry makes the automobile's price fall continously. And automobile plays a major role in daily life and work. The important questions for transport and safety management to face are how to command and navigate effectively, and control coordinately to avoid traffic congestion, improve transport efficiency and protect transport safety to all automobiles. The car navigation system is the electronic product used global positioning system in car positioning navigation. To some extent, it ensures the purpose of the mobile transport and the safety and effectiveness in the movement. The car navigation system is an effective method to solve the above problems.Along with the continous progress of technology, navigation instrument in-car with automobile radio system, integrates modern communicated technology, and provides various navigation information, such as directions, road conditions and congestions of traffic, through the radio of system timely and effectively. Navigation instrument in-car with automobile radio system is very useful, so it has a broad market prospect. There is a positive significance for raising the level of traffic management and transport efficiency.In this thesis, a navigated car radio system is designed based on single-chip microcomputer control technology. In consideration of the system's performance, software design and implementation's difficulty level, the whole design scheme of the system is put forward. A kind of single-chip microcomputer specially used in car radio system is chosen as the system's central microcontrol unit. To achieve the goals and requirements, control module, reception module, modulation module, power module and key and display module are designed respectively. The system provides navigation information of traffic reports to the users and realizes the functions of manually and automatically searching channels, multilevel volume adjusting, high luminous LCD display, high-quality audio output and so on.The working environment of the navigated car radio system is complex and vulnerable to noise interference. In many cases, noises' external characteristic is unknown, and its transmission channels are constantly changing. In this situation, adaptive noise canceling algorithm based on Least Mean Sqare (LMS) algorithm is used in the thesis to denoise audio signals, and the denoising approach is also given. After researching the effection of fixed step and variable step algorithm to learning curve in linear prediction and model recognition, and analyzing and comparing the convergence speed and steady state error, the improved variable step LMS algorithm is raised. Through simulating research under Matlab situation, this improved algorithm makes a more satisfactory result in audio signal de-noising.