This system will have one main function: To interpret an incoming MP3 bitstream and reconstruct the original signal. The TMS320C6x DSP will be used to do the decoding and produce the original signal on an audio output port of the DSP. The system will be controlled by various user inputs. The MP3 bitstream will be stored in the memory of the TMS320Cx evaluation module. It is hoped that the quality of the output signal will be comparable to that of a CD player.
Figure 1 shows the very basic functionality of the system. The outputs and inputs of the system are described in Table 1.
| Table 1: System Inputs and Outputs | ||
| MP3 Bitstream | Encoded MP3 bitstream. Sequence of many frames, each containing a header, error checking bits, miscellaneous information, and encoded data. This encoded bitstream will be uploaded off of a PC into the memory available on the evaluation module. Encoded MP3 files are available for download on the internet, or may be created on a PC with shareware software packages. | |
| Audio Output | Single PCM coded signal. This signal should sound identical to the original audio signal. | |
| User Controls | ||
| Power On/Off | Turns the decoder on and off. | |
| Play | Begins decoding the bitstream. | |
| Stop | Stops decoding the bitstream. | |
| Forward | Skips forward in the bitstream. | |
| Back | Rewinds to the beginning of the song. | |
| Shuffle | Randomizes the play order of the songs in memory. | |