Abstract:
A method is provided for transmitting audio signals from at least one hi-fi signal source to at least one hi-fi signal sink, wherein the audio signals are compressed in the MP3 compression standard and then transmitted from the at least one hi-fi signal source to the at least one hi-fi signal sink via the Bluetooth radio standard and in a single Bluetooth radio channel.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a method for transmitting of audio signals from at least one hi-fi signal source to at least one hi-fi signal sink, in which the audio signals are transmitted from the at least one hi-fi signal source to the at least one hi-fi signal sink in a manner compressed in a digital radio standard.  
           [0002]    Such a method is disclosed in the published European patent application 0 865 170 A1. In this previously known method, audio information from a hi-fi system operating as a hi-fi signal source is firstly compressed to the ATRAC method. The audio signals compressed in this way are subsequently transmitted in the DECT standard (DECT: Digital Enhanced Cordless Telecommunications) to a hi-fi signal sink. The hi-fi signal sink may be, by way of example, headphones, a loudspeaker or an amplifier.  
           [0003]    This published patent application additionally discloses a hi-fi signal sink with a receiving device for receiving compressed radio transmitted audio signals from a hi-fi signal source.  
           [0004]    Moreover, this published application discloses a hi-fi signal source with a radio device for transmitting compressed audio signals to a hi-fi signal sink.  
           [0005]    The present invention is directed toward a method for the transmission of audio signals in which audio signals from a number of hi-fi signal sources can be transmitted simultaneously to a hi-fi signal sink or to a number of hi-fi signal sinks.  
           [0006]    The present invention is also directed toward a hi-fi signal sink with a receiving device for receiving compressed radio transmitted audio signals from a hi-fi signal source wherein the audio signals from a number of hi-fi signal sources can be received simultaneously.  
           [0007]    The present invention is further directed toward a hi-fi signal source with a radio device for transmitting compressed audio signals to a hi-fi signal sink wherein the source can be operated together with further hi-fi signal sources such that audio signals from a number of hi-fi signal sources can be transmitted simultaneously to one or a number of hi-fi signal sinks.  
         SUMMARY OF THE INVENTION  
         [0008]    Proceeding from a method of the type specified in the introduction, the radio standard used by the present invention is the Bluetooth radio standard, and all the audio signals are transmitted in a manner compressed in the MP3 compression standard in a single Bluetooth radio channel. The “Bluetooth” transmission technique is described in Funkschau 23/99 “Code-Name Bluetooth”, pages 80 and 81, by W. Schulte, and in Funkschau 13/99 “Die ersten Bluetooth-Produkte”, [“The first Bluetooth products”], pages 38 and 39, by M. Kotynek-Friedl. In this case, the “MP3 compression” is understood to be compression according to the MPEG layer 3 standard (ISO-MPEG Audio Layer 3 (e.g. IS11172-3 or IS13818-3)).  
           [0009]    A key advantage of the method according to the present invention is that MP3 data compression is combined with the Bluetooth radio standard, because the data rate of an audio signal which is compressed according to the MP3 standard is matched very well to the transmission rate of a Bluetooth radio channel. Thus, the data rate of a stereo audio channel after MP3 data reduction is approximately 100 kilobits per second and is, thus ideally matched to the transmission rate of a Bluetooth channel, which has a data rate of up to one megabit per second. In the case of the method according to the present invention, therefore, it is possible to transmit the audio signals from a number of hi-fi signal sources simultaneously in a single Bluetooth radio channel, to be precise up to 10 different audio signals in parallel. If one of the hi-fi signal sinks is a set of hi-fi headphones, for example, then the user of the hi-fi headphones could, in each case select the audio signal which he/she would actually like to hear. To summarize, in the case of the method according to the present invention, in contrast to the previously known DECT transmission method, it is always the case that use is only ever made of a single Bluetooth radio channel. As a result, a flexible system is achieved in which audio signals from different hi-fi signal sources can be received simultaneously.  
           [0010]    It is advantageous if a remote control device is used for driving the at least one hi-fi signal source and/or the at least one hi-fi signal sink, which device transmits its control signals in the Bluetooth radio channel to the at least one hi-fi source and/or to the at least one hi-fi signal sink. This is because, in accordance with this development of the method according to the present invention, the Bluetooth radio channel that is present anyway for the transmission of the audio signals is additionally used also for the transmission of control signals.  
           [0011]    Also according to the present invention, a signal sink is used which is suitable for the reception and reproduction of audio signals which are compressed according to the MP3 compression standard and are transmitted according to the Bluetooth radio standard, such that audio signals from a number of hi-fi signal sources can be received_simultaneously.  
           [0012]    The present invention incorporates a hi-fi signal source which is suitable for the compression of the audio signals according to the MP3 compression standard and for the transmission of the compressed audio signal according to the Bluetooth radio standard, wherein the source can be operated together with hi-fi signal sources such that audio signals from a number of hi-fi signal sources can be transmitted simultaneously to one or a number of hi-fi signal sinks.  
           [0013]    Additional features and advantages of the present invention are described in, and will be apparent from, the following Detailed Description of the Invention and the Figures. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0014]    [0014]FIG. 1 shows an exemplary embodiment of an arrangement which can be used to carry out the method according to the present invention.  
         [0015]    [0015]FIG. 2 shows an exemplary embodiment of a hi-fi signal sink according the present invention.  
         [0016]    [0016]FIG. 3 shows an exemplary embodiment of a hi-fi signal source according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    [0017]FIG. 1 shows a Bluetooth microcell  10 , which is formed by a hi-fi signal source  20 , a further hi-fi signal source  30 , a hi-fi signal sink  40  and a further hi-fi signal sink  50  and a remote control device ST. The two hi-fi single sources, the two hi-fi signal sinks and the remote control device ST are in a Bluetooth radio connection among one another, which is represented diagrammatically in FIG. 1 by arrows bearing the reference symbol  60 . In this case, the Bluetooth radio connection is formed by a single Bluetooth radio channel. In this Bluetooth radio channel, the data signals are transmitted with a data rate of up to one megabit per second.  
         [0018]    As can be gathered from FIG. 1, the one hi-fi signal source  20  is connected both to the one signal sink  40  and to the further signal sink  50 . The same applies to the further signal source  30 , which is connected both to the one signal sink  40  and to the further signal sink  50 . Thus, the audio signals from both hi-fi signal sources  20  and  30  are present at each of the two signal sinks  40  and  50 , so that the audio information from both hi-fi signal sources can be received by each of the two signal sinks.  
         [0019]    This will be illustrated using an example. If the one signal source  20  is a CD player, for example, and the further hi-fi signal source  30  is a radio, then both the audio information from the CD player and the audio information from the radio can be received in both hi-fi signal sinks  40  and  50 . If the two hi-fi signal sinks  40  and  50 , respectively, are headphones, for example, then a user of the headphones can decide such as by a corresponding switching device which audio information he/she would like to receive. Thus, the user can decide whether he/she wishes to receive the audio information from the CD player  20  or the audio information from the radio  30 . With the control device ST, the user can additionally generate control signals for driving the two signal sinks  40  and  50  and the two signal sources  20  and  30 .  
         [0020]    [0020]FIG. 2 illustrates an exemplary embodiment of a hi-fi signal source  100 . The hi-fi signal source  100  has an audio signal source  110 , which may be, by way of example, a CD player, a radio, a disc player or the like. The audio signal source  110  is connected by its signal output A 110  to a data input D 120  of an MP3 coding device  120 . A Bluetooth radio device  130  is arranged downstream of the MP3 coding device  120  on the output side.  
         [0021]    The hi-fi signal source  100  can be operated as follows. Audio information SI from the audio signal source  110  pass via the output A 110  of the audio signal source  110  to the MP3 coding device  120 . In the MP3 coding device  120 , the audio information is subjected to MP3 coding to form compressed audio signals SI′. The compressed audio signals SI′ pass to the Bluetooth radio device  130 , which transmits the compressed audio signals SI′ as Bluetooth radio signals SI″.  
         [0022]    [0022]FIG. 3 shows an exemplary embodiment of a hi-fi signal sink  200 . The hi-fi signal sink  200  has a Bluetooth receiving device  210 , downstream of which is connected, at an output A 210 , an MP3 decoding device  220  by its data input D 220 . On the output side, the MP3 decoding device  220  device is connected to an audio reproduction device  230 , which may be, by way of example, a set of headphones, a loudspeaker or an amplifier. The hi-fi signal sink in accordance with FIG. 3 can be operated as follows. The Bluetooth receiving device  210  receives Bluetooth radio signals SI″, which may originate, for example, from a hi-fi signal source such as that in accordance with FIG. 2. The Bluetooth radio signals SI″ pass to the MP3 decoding device  220 , in which decoded audio signals SI′″ are obtained from the Bluetooth radio signals. The decoded audio signals SI′″ pass to the audio reproduction  230 , which converts the decoded audio signals SI′″ into acoustic waves, for example, and outputs the latter.  
         [0023]    Although the present invention has been described with reference to specific embodiments, those of skill in the art will recognize that changes may be made thereto without departing from the spirit and scope of the present invention as set forth in the hereafter appended claims.