Research And Development For The Realization Of Car MP3 Tuner Based On USB-OTG Data Interface

The car MP3 tuner is a type of digital audio mainframe for the upgrading of car pioneer audio market. The existing car audio products are the combination of a CD player and the radio. With the intrinsic feature, the CD player has such shortcomings as poor anti-shocking ability, the aging of the laser reader, and the inconvenience of changing the disk. Excepting for overcoming the above defects, the car MP3 tuner has the advantages of easy download of audio files and updating at any time. As the present MP3 products dominated on the market play the audio files by using the emission patter of FM/AM, the acoustic fidelity becomes less desired in this electric current to electric wave and electric wave to electric current conversion mode, and it is vulnerable to the external interference. This mainframe will not be able to choose the songs to be played and it is not convenient to use. Therefore, the non-frequency modulation MP3 tuner has a more extensive domain for application.This article proposes an overall design program to access to the audio files, which are stored in the U disk in the FAT16/32 file system, by using the USB OTG data interface. The digital phase-locked loop technology is employed to control the digital-adjustment of radio and complete the audio frequency processing using other audio frequency decoding module. The novelty of the articles is that the components are original and simple with diverse functions and low cost when compared with the comparable products on the market in term of designing and realizing the function of the products. The design of the system mainly includes the four following parts: the FM/AM high frequency receiving module, USB OTG data access module, MP3/WMA audio decoding module, the user input and display panel and the master control module.This article elaborates in the main part the principle that the FM/AM high frequency module receives the high frequency and demodulate it and the principle that the digital phase-locked loop completes digital harmonious, the access of the interface data and the completion of data access by the MP3/WMA audio frequency decoding module and the work of the main master control unit. It elaborates the process of development of the USB MP3 tuner and provides a preliminary plan for this purpose.