High-fidelity Music Player Based On ARM9

As digital audio technology continues to improve, high-quality, high-performance digitalaudio compression format after another, support these compressed formats music players haveemerged, people will always be able to listen to the music to feel the beauty of life. In order topursue high-quality music playback, music lovers from the beginning, only concerned with asimple objective indicators of sound playback, distracted to connect these objective indicatorsof sound playback with people’s subjective sense of hearing, in order to achieve a high degreeof sound recover, to experience the live music music, therefore, high-fidelity music player onas a new product appear.From the issue of high-quality playback of lossless audio format music point of view, toachieve a high quality music player based on ARM9. Compared with the traditional players, ithas three unique features: First, the USB plug can be used as the audio decoder to compensatefor the low accuracy of home computers in the DAC defects; Secondly, as a light receiving ortransmitting data coaxial digital DAC used to reduce the data transfer process due to clock jittercause the data error rate increases; Finally, as a dedicated high-quality music player, to achievea perfect reproduction of music.In the field of professional digital audio, data conversion is commonly used with highprecision digital to analog converter to ensure high-fidelity audio signal to be restored out ofthe D/A to improve the accuracy by sampling techniques, to improve the accuracy of thesampling frequency for and, therefore, during the conversion, oversampling interpolation filter,the frequency of the digital signal to the Nyquist frequency of8times, which reduces the levelafter the order analog filters. The topic chosen DF1706achieve8times interpolation filter,digital-analog conversion by the delta-Sigma architecture of PCM1704completed, after theclass through the third-order low-pass filter output GIC convert the sound signal. When thedigital signal output by the transmitter, receiver and demodulated by the receiver when the datareference clock due to jitter cause data bit error, thus reducing clock jitter is the key to thisresearch, in order to reduce the transmission error rate, the choice of chips PCM2707andDIR9001to USB interface for receiving, respectively, and coaxial, optical data transmissioninterface. In order to improve overall system accuracy and data processing functions of themanagement, use low-power, high-performance S3C3440as the core of the smallest systemsand Linux operating system as the basis, the use of QT and Qtopia development environmentfor the software to realize the player application GUI interface, transplantation with a variety ofopen source decoder Mplayer music player, the GUI program interface and Mplayer completedthe perfect link, by software testing, achieve a player to play, pause, fast forward, rewind, onthe one, the next a basic function, download the software to the hardware platform, the use ofaudio-specific measurement software SpectraLAB obtain the overall performance of the testresults, for high-fidelity audio products and implementation of research laid the foundation.