Dynamic information storage or retrieval – Combined independent audio systems – Radio
Reexamination Certificate
1999-10-15
2001-09-18
Dinh, Tan (Department: 2651)
Dynamic information storage or retrieval
Combined independent audio systems
Radio
Reexamination Certificate
active
06292440
ABSTRACT:
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to a Moving Picture Experts Group (MPEG) audio layer-3 (MP3) player. More specifically, the present invention relates to a MP3 car player equipped with a compact disk (CD) player in which interruptions in the playing of CDs caused by bumpy road conditions, etc. are prevented, and which is able to compress and decompress digital audio data at high compression rates without loss of sound quality.
(b) Description of the Related Art
Conventional car CD players use a memory in order to prevent discontinuous sound playing. However, the small capacity of the memory is such that these interruptions can not be completely prevented. Also, since the CD player only plays audio CDs, the CD player cannot process data on the CD Read Only Memory (CD-ROM) which holds far greater compression rates.
In most cases, the MP3 player is used together with a personal computer (PC) which performs downloading and decoding of audio data before uploading into the player. Since the PC utilizes software to perform these functions, the MP3 player is ultimately dependent on the performance of the PC, thereby making real-time implementation difficult unless the user owns a top-of-the-line PC. Such use together with a PC also limits portability. Further, even if the MP3 player is equipped allowing full portability (i.e., to internally perform downloading and decoding), high power consumption is a serious drawback that results in a reduced amount of time the user can use the MP3 player on battery power.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an MP3 car player having a large memory allowing audio data to be temporarily stored and output, and which can use both the conventional CD and CD-ROM, thereby removing the need for the expensive CD changer often used together with CD players installed in automobiles.
It is another object of the present invention to provide an MP3 car player which implements the use of an MPEG audio layer-3 chip to drive an MPEG decoder, and realizes the integration of peripheral circuits and an interface unit in a separate, single chip.
In one aspect of the present invention, the MP3 car player comprises a display unit displaying information of replaying audio data; a keypad controlling drives of compact disks (CDs) and compact disk read only memories (CD-ROMs); a speaker unit outputting the audio data in a format audible to the human ear; a file type detector reading source data of the CDs and CD-ROMs and determining whether the file of the data is an ordinary audio CD file or an MP3 audio file; an MP3 file input unit receiving the MP audio file detected from the file type detector, and detecting errors and temporarily storing the data in a first memory; an MP3 decoder receiving the MP3 data from the MP3 file input unit and restoring compressed data by use of a Huffman decoding method, and converting the data into pulse code modulation data; a controller unit reading the data stored in the MP3 file input unit, controlling the display unit and the keypad, and writing data to the MP3 decoder; a peripheral interface unit controlling the control signals between the display unit, the keypad, and the controller unit; and a digital/analog converter receiving ordinary audio CD data from the file type detector or receiving pulse code modulation digital data from the MP3 decoder and converting the data into analog data and outputting the data to the speaker unit.
The MP3 file input unit comprises an integrated development environment (IDE) interface unit receiving MP3 audio files determined by the file type detector and performing IDE communications for use in a memory card; an error detector receiving the MP3 file data through the IDE interface unit and checking whether or not the data are normally received, and when errors are detected in the data, returning to an initialization step; and a memory block receiving addresses of a second memory, chip selection signals, and read and write signals from the controller, and controlling the second memory when temporarily storing the errorless MP3 data in the first memory in order to decode the errorless data before transmitting the data to the MP3 decoder.
The peripheral interface unit comprises a display interface unit performing interface operations on displaying items such as titles of audio data or track numbers on the display unit; and a keypad interface unit controlling the operations between the keypad and the controller, the operations including controlling keys which operate the CDs and CD-ROMs and selecting rows and columns of the keypad.
The controller unit comprises a controller reading the data stored in the MP3 file input unit, and displaying information of the audio data on the display device, and outputting the data to the MP3 decoder according to input from the keypad; and a third memory storing instructions to drive the controller, address map information, and bootstrap signals to initialize the operation when power is supplied.
The MP3 decoder comprises an MP3 interface unit handling the data received from the MP3 file input unit for each serial bit; a control and status register controlling a response signal which conveys information of whether or not the data provided to the MP3 interface unit have errors to the controller, and displaying an empty or full status of the provided data; a fourth memory receiving serial data from the MP3 interface unit and storing the data; a parser receiving data from a fifth memory and encoding the data using the Huffman decoding method; an inverse modified discrete cosine transform unit performing inverse modified discrete cosine transform on the data encoded from the parser, and transforming the data into pulse code modulation data; a sixth memory temporarily storing the pulse code modulation data; and a pulse code modulation interface unit receiving the pulse code modulation data from the sixth memory and outputting the data to the digital/analog converter.
REFERENCES:
patent: 6061306 (2000-05-01), Buchheim
patent: 2000105598 (2000-04-01), None
patent: 200014944 (2000-05-01), None
Dinh Tan
Fish & Richardson P.C.
IDS Corporation
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