Abstract:
A portable music player includes an external memory connector for connecting to a removable memory device containing digital music files, a user interface operable to allow a user to select and access the digital music files stored in the removable memory device, a decoder for converting selected digital music files into audio signals, and an audio output port for outputting the audio signals.

Description:
BACKGROUND OF INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a portable music player, and more specifically, to a portable music player used in conjunction with a plurality of removable storage devices, the removable storage devices each containing digital music files to be played on the portable music player.  
           [0003]    2. Description of the Prior Art  
           [0004]    With the advent of digital music being readily available, users have a new source of musical content. Digital music content resides in relatively small digital files that can be stored on portable non-volatile memory devices. Due to the popularity of digital music, portable music players such as Moving Pictures Expert Group, Layer 3 (MP3) players, as well as other types of music players can be found everywhere.  
           [0005]    Please refer to FIG. 1 and FIG. 2. FIG. 1 is a diagram of a portable music player  10  according to the prior art. FIG. 2 is a functional block diagram of the portable music player  10  shown in FIG. 1. The portable music player  10  contains a memory  16  such as a flash memory for storing digital music files. Currently, music files in the MP3 format are commonly used in the portable music player  10  due to their small file sizes. The portable music player  10  contains an external connector  14  such as a male USB connector for allowing the portable music player  10  to connect to a host device such as a computer. The portable music player  10  connects to the host device for transferring digital music files from the computer to the portable music player  10 , and vice versa. A controller  20  is used for controlling operations of the portable music player  10 . The portable music player  10  contains a decoder  18  for converting the digital music files stored in the memory  16  into analog audio signals. In addition to playing digital music files stored in the memory  16 , the portable music player  10  also contains a radio receiver  22  for playing radio signals received on FM and AM radio stations.  
           [0006]    The portable music player  10  contains a display  12  for indicating an operating state of the portable music player  10  to a user. For instance, the title of the current song or the radio station being played can be indicated on the display  12  along with information about the battery life of the portable music player  10 . An audio output port  24  allows the user to hear the music being played on the portable music player  10 . The audio output port  24  is typically an earphone jack, although a speaker can be used instead of or in addition to the earphone jack.  
           [0007]    The portable music player  10  is popular for its small size and its simple design with no moving parts. However, the portable music player  10  has a fixed amount of memory  16  available for storing digital music. As an example, suppose that the memory  16  has a capacity of 64 MB, which can store about one hour of digital music in the MP3 format. If the user of the portable music player  10  wishes to go on an extended trip, he will quickly run out of new songs to listen to on the portable music player  10  due to the small capacity of the memory  16 . In addition, if the user wishes to change the songs on the portable music player  10 , the user must connect the portable music player  10  to the host device for updating the songs stored in the memory  16  of the portable music player  10 . During this updating process, the host computer treats the portable music player  10  as a slave device, and controls all file transferring processes. It should be noted that the user interface of the portable music player  10  cannot be used to read files on the host computer. The portable music player  10  can only read files once they are stored in the memory  16  of the portable music player  10 . The portable music player  10  cannot be freely carried around during process of updating the songs in the memory  16 . In order to overcome these problems, the user must buy multiple portable music players  10 . If two or more portable music players  10  are used, one portable music player  10  can be freely carried around and listened to while another portable music player  10  is updated with a host device. Unfortunately, having more than one portable music player  10  greatly increases the cost associated with enjoying digital music.  
         SUMMARY OF INVENTION  
         [0008]    It is therefore a primary objective of the claimed invention to provide a portable music player that can be connected to a removable memory device in order to solve the above-mentioned problems.  
           [0009]    According to the claimed invention, a portable music player includes an external memory connector for connecting to a removable memory device containing digital music files, a user interface operable to allow a user to select and access the digital music files stored in the removable memory device, a decoder for converting selected digital music files into audio signals, and an audio output port for outputting the audio signals.  
           [0010]    It is an advantage of the claimed invention that the portable music player can be connected to removable memory devices for eliminating constraints on a capacity of the memory of the portable music player. A user may use as many removable memory devices as necessary for storing digital music, and can simply insert a chosen removable memory device into the portable music player to listen to songs on the chosen removable memory device.  
           [0011]    These and other objectives of the claimed invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0012]    [0012]FIG. 1 is a diagram of a portable music player according to the prior art.  
         [0013]    [0013]FIG. 2 is a functional block diagram of the portable music player shown in FIG. 1.  
         [0014]    [0014]FIG. 3 is a diagram of a portable music player connected to a removable memory device according to the present invention.  
         [0015]    [0015]FIG. 4 is a functional block diagram of the portable music player and the removable memory device shown in FIG. 3. 
     
    
     DETAILED DESCRIPTION  
       [0016]    Please refer to FIG. 3 and FIG. 4. FIG. 3 is a diagram of a portable music player  100  connected to a removable memory device  180  according to the present invention. FIG. 4 is a functional block diagram of the portable music player  100  and the removable memory device  180  shown in FIG. 3. The portable music player  100  of the present invention is similar to the portable music player  10  of the prior art. However, the portable music player  100  is capable of connecting to the removable memory device  180  for increasing the memory capacity of the portable music player  100 . The removable memory device  180  contains a memory  182  for storing digital music. Please note that the removable memory device  180  can be realized with a standard off-the-shelf USB portable storage device, which usually contains flash memory for the memory  182 . The portable music player  100  contains a first external connector  114  for connecting to a second external connector  184  of the removable memory device  180 . The first external connector  114  is preferably a female USB connector and the second external connector  184  is preferably a male USB connector, as shown in FIG. 3.  
         [0017]    One or more removable memory devices  180  can be used in conjunction with the portable music player  100  for storing digital music that can be played through the portable music player  100 . In this way, the portable music player  100  has no limit on the amount of memory that can be used to store digital music. The removable memory device  180  can be connected to a host computer for downloading digital music onto the memory  182  of the removable memory device  180 . Once the desired digital music is stored on the memory  182 , the removable memory device  180  can be disconnected from the host device and connected to the portable music player  100 . Once the removable memory device  180  is connected to the portable music player  100 , the portable music player  100  treats the removable memory device  180  as a slave device, and the user interface of the portable music player  100  allows files to be selected and read from the memory  182  of the removable memory device  180  through the first external connector  114  and the second external connector  184 .  
         [0018]    A controller  120  is used for controlling operations of the portable music player  100 . The portable music player  100  contains a decoder  118  for converting the digital music files stored in the memory  182  into analog audio signals. The decoder  118  may be capable of decoding more than one format of digital music, such as the MP3 and Windows Media Audio (WMA) formats, into analog audio signals. In addition to playing digital music files stored in the memory  182 , the portable music player  100  also contains a radio receiver  122  for playing radio signals received on FM and AM radio stations.  
         [0019]    The portable music player  100  contains a display  112  for indicating an operating state of the portable music player  100  to a user. For instance, the title of the current song or the radio station being played can be indicated on the display  112  along with information about the battery life of the portable music player  100 . An audio output port  124  allows the user to hear the music being played on the portable music player  100 . The audio output port  124  is typically an earphone jack, although a speaker can be used instead of or in addition to the earphone jack.  
         [0020]    When the portable music player  100  is not connected to the removable memory device  180 , the portable music player  100  can still be used to listen to the radio through the radio receiver  122 . If the portable music player  100  does not contain any internal memory, the removable memory device  180  has to be connected to the portable music player  100  in order to listen to digital music songs stored on the memory  182 . Alternatively, the portable music player  100  can be designed to contain optional internal memory, which would allow the user to listen to songs while the removable memory device  180  is temporarily disconnected from the portable music player  100 .  
         [0021]    Compared to the prior art portable music player  10 , the present invention portable music player  100  is not limited to a fixed size memory capacity. A plurality of removable memory devices  180  can be used in conjunction with the portable music player  100  to provide a limitless amount of memory that can be used to store digital music. Therefore, only one portable music player  100  is needed, and the removable memory device  180  can be bought independently using off-the-shelf portable storage devices. Since there is no limit to the size of the memory that can be used to store digital music played through the portable music player  100 , users can always be assured of having enough music to listen to on long trips.  
         [0022]    Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.