Patent Publication Number: US-8126181-B2

Title: Acoustic system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present invention contains subject matter related to Japanese Patent Application JP 2005-299188 filed in the Japanese Patent Office on Oct. 13, 2005, the entire contents of which being incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an acoustic system applicable to a portable telephone system which outputs music with high-quality reproduced from a portable telephone connected to, for example, a cradle. 
     2. Description of the Related Art 
     A portable telephone system in which a portable telephone terminal is mounted on a charging stand as a main unit for charging through a charging terminal of the charging stand, and is adapted to output an audio sound obtained by reproducing music data by the portable telephone terminal from a speaker of charging stand built in the charging stand (for example, refer to Jpn. Pat. Appln. Laid-Open Publication No. 2003-283609). 
     SUMMARY OF THE INVENTION 
     However, in a portable telephone system of such a configuration, the size of the charging stand speaker is restricted in accordance with the miniaturization of the charging stand which mounts the portable telephone terminal. For this reason, it has been difficult to enlarge the diameter of cone paper in the charging stand speaker. Therefore, there is a problem that a low range audio sound outputted from the charging stand speaker is insufficient. 
     The present invention has been made in consideration of the above-mentioned points. This invention provides an acoustic system which can provide a richly expressive acoustic space without enlarging the size of a main unit. 
     An acoustic system of the present invention to solve such a problem comprises a power supply adapter carrying a woofer unit which outputs a low range audio sound according to an audio signal, a main unit carrying speaker units which output a mid-high range audio sound according to the audio signal, and a transmission cable which connects the power supply adapter to the main unit and transmits the audio signal to the power supply adapter from the main unit to output the low range audio sound from the woofer unit. 
     Therefore, this acoustic system outputs the mid-high range audio sound according to the audio signal from the speaker units of the main unit, and further the low range audio sound according to the audio signal transmitted from the main unit through a transmission cable from the woofer unit of the power supply adapter. Accordingly, a richly expressive acoustic space can be provided without enlarging the size of the main unit. 
     According to one embodiment of the present invention, in addition to output the mid-high range audio sound of the audio signal from the speaker units of the main unit, the present invention can output the low range audio sound of the audio signal transmitted from the main unit through the transmission cable can be outputted from the woofer unit of the AC adapter. Accordingly, the acoustic system which can provide a richly expressive acoustic space can be realized without enlarging the size of the main unit. 
     The nature, principle and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings in which like parts are designate by like reference numerals or characters. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIG. 1  is a schematic perspective view showing an overall configuration of an acoustic system of the present invention; 
         FIG. 2  is a schematic perspective view showing a front surface structure of a main unit; 
         FIG. 3  is a schematic perspective view showing a back surface structure of the main unit; 
         FIG. 4  is a schematic perspective view showing a charging state of a portable telephone with music reproducing function; 
         FIG. 5  is a schematic block diagram showing a circuit configuration of the main unit and an AC adapter; and 
         FIG. 6  is a schematic view provided to explain the superimposition of music data to a DC power supply transmission cable. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. 
     (1) Overall Structure of Acoustic System 
     In  FIG. 1 , reference numeral  1  shows an acoustic system of 2.1 channel of the present invention as a whole. The acoustic system comprises a main unit  2  for charging a portable telephone with music reproducing function (to be described later), an Alternating Current (AC) adapter  3  for supplying a Direct Current (DC) power of predetermined voltage level to the main unit  2 , and a DC power transmission cable  4  for connecting the main unit  2  and the AC adapter  3 . 
     The AC adapter  3  is adapted to operate the main unit  2  by converting a voltage of AC100 V supplied from an AC plug  5  connected to a commercial AC power supply (not shown) into a voltage of DC12 V and supplying the DC power of the DC12 V to the main unit  2  through the DC power supply transmission cable  4 . 
     (2) External Structure of Main Unit 
     As shown in  FIG. 2 , the main unit  2  has a body  11  having a triangular prism shape. A charging stand  12  having a half-circular thin plate shape is projected from the substantially central portion of the body  11  in a longitudinal direction. A connection terminal for charging stand  13  or electrically connecting the connection terminal for the terminal of the portable telephone with music reproducing function (to be described later) is provided to the charging stand  12 . 
     Further, the main unit  2  has a left speaker  14  and a right speaker  15  which mainly output mid-high range audio sound, provided at both sides of the charging stand  12 . A cover  10  made of metal having lattice-shape pores, is attached to cover and conceal the left speaker  14  and the right speaker  15  in the main unit  2 . 
     Furthermore, the main unit  2  has a function switch  16  provided at the right side upper end of the body  11 , a volume up button  17  and a volume down button  18  provided adjacent to the function switch  16 , a power display Light Emitting Diode (LED)  19  showing a power on state, provided at the left side upper end of the body  11 , a line-in display LED  20  showing the connection of an external electronic apparatus through a line input terminal (to be described later), and a surround display LED  21  showing that a surround function becomes on state through an infrared remote controller (not shown). 
     Incidentally, the main unit  2  has a light receiver  22  for the infrared remote controller, provided in the inside of the cover  10 . A control command from the infrared remote controller is received by the light receiver  22  and the above-mentioned surround function is adapted to be turned on based on the control command. 
     On the other hand, as shown in  FIG. 3 , the main unit  2  has a DC input terminal  25  for receiving the supply of the DC power of DC12 V from the AC adapter  3  through the DC power supply transmission cable  4  at the right side lower end of the back surface of the body  11 . The main unit  2  also has a line input terminal  26  for inputting the music signal from the external electronic apparatus (not shown) adjacent to the DC input terminal  25 . 
     Therefore, as shown in  FIG. 4 , when the portable telephone with music reproducing function  6  is mounted on a connection terminal for charging stand  13  (not shown) of the charging stand  12  in the state that the main unit  2  receives the supply of the DC power of the DC12 V from the AC adapter  3  through the DC power supply transmission cable  4 , the connection terminal for charging stand  13  is electrically connected to the connection terminal for charger (not shown), provided at the lower end of the portable telephone with music reproducing function  6 , and then charging is started. 
     Incidentally, when the connection terminal for terminal of the portable telephone with music reproducing function  6  is electrically connected to the connection terminal for charging stand  13  of the charging stand  12 , the main unit  2  inputs the music signal reproduced from an internal memory by the portable telephone with music reproducing function  6  through the connection terminal for charging stand  13 , and outputs the sounds based on the music signal from the left speaker  14  and the right speaker  15 . 
     (3) External Structure of AC Adapter 
     Incidentally, the AC adapter  3  ( FIG. 1 ) is composed of a body  31  having a quadrangular prism shape that shows a trapezoidal cross section. The AC adapter  3  has a power amplifier  32  and a sub-woofer  33  in the inside thereof. 
     The AC adapter  3  has a power switch  34  provided on a front surface  31 A of the body  31  to switch on/off of a power supply. The AC adapter  3  also has a port  35  for the sub-woofer  33  concealed in the inside of the body  31 . The low range audio sound outputted from the sub-woofer  33  is outputted from the port  35  in the state that the low range audio sound is increased to a higher pitch. Thus, the low range audio sound is supplemented to the mid-high range audio sound outputted from the left speaker  14  and the right speaker  15  of the main unit  2 . 
     As described above, the AC adapter  3  need to cover the low range audio sound only by the sub-woofer  33  but does not need to output the mid-high range audio sound. Accordingly, the AC adapter  3  can be formed in a concealing structure which does not expose the sub-woofer  33  from the front surface of the body  31  to the exterior. Thus, a user does not sense that the sub-woofer  33  is built in the AC adapter  3 . 
     Incidentally, the AC adapter  3  is composed of a speaker unit of so-called a Kelton type that the front surface of the woofer of the sub-woofer  33  is concealed by the body  31 . However, the AC adapter  3  is not limited to the Kelton type and the other types of speaker unit, such as a bass-reflex type, a double bass-reflex type, etc., may constitute the AC adapter  3 . 
     (4) Circuit Structure of Main Unit and AC Adapter 
     Next, the circuit configuration of the main unit  2  and the AC adapter  3  will be described by using  FIG. 5 . The main unit  2  controls the entire system by an Micro Processing Unit (MPU)  40 , and is adapted to operate the entire system based on a DC power DC supplied from the AC adapter  3  through the DC power supply transmission cable  4 . 
     This main unit  2  inputs the music signal supplied from the portable telephone with music reproducing function  6  connected through the connection terminal for charging stand  13  to an input selector  41  and also inputs the music data supplied from the external electronic apparatus connected through the line input terminal  26  to the input selector  41 . 
     The input selector  41  preferentially selects the music signal supplied as default from the portable telephone with music reproducing function  6  through the connection terminal for charging stand  13 , and sends the music signal to an Analog/Digital (A/D) converter  42 . 
     Incidentally, the MPU  40  of the main unit  2  is adapted to select preferentially the music signal supplied from the external electronic apparatus based on a key signal S 1  inputted according to a user&#39;s pressing operation with respect to a function key  16  and send the music signal supplied from the external electronic apparatus to the A/D converter  42 . That is, the main unit  2  can selectively switch any of the music signal from the portable telephone with music reproducing function  6  or the music signal from the external electronic apparatus according to the user&#39;s pressing operation with respect to the function switch  16 . 
     The A/D converter  42  converts the audio signal into digital music data MD 1  and sends the music data MD 1  to a digital signal processor  43 . The digital signal processor  43  performs predetermined digital signal processing to the music data MD 1  and sends the thus processed music data MD 1  to a class D amplifier  44  and a digital interface transmitter  45 . 
     The class D amplifier  44  performs an amplifying process to the digital signal processed music data MD 1 . The class D amplifier  44  then outputs the thus obtained sounds according to the left channel music signal and right channel music signal from the left speaker  14  and the right speaker  15 . 
     The digital interface transmitter  45  converts the digital signal processed music data MD 1  into serial data format music data SMD 1  and sends the serial data format music data SMD 1  to a superimposing circuit  46 . 
     Incidentally, the MPU  40  of the main unit  2  is adapted to regulate the sound volume level of the music or sound data MD 1  outputted from the digital signal processor  43  based on a control signal S 2  inputted corresponding to the user&#39;s pressing operation with respect to the volume up button  17  and the volume down button  18 . 
     Note that, the MPU  40  of the main unit  2  outputs an LED control signal S 3  according to the operating state of the main unit  2 . Thereby, the MPU  40  of the main unit  2  can control to light the power display LED  19 , the line-in display LED  20  and the surround display LED  21 . 
     On the other hand, the AC adapter  3  inputs the AC power of AC100 V supplied from a commercial AC power supply to a switching (SW) power supply circuit  50  of the power supply amplifier  32 . The SW power supply circuit  50  converts the AC power of AC100 V into a DC power DC of DC12 V. Then, the SW power supply circuit  50  supplies the DC power DC of DC12 V to an MPU  52 , a receiver  53  and a class D amplifier  54  through a separating circuit  51 . 
     Further, the AC adapter  3  supplies a DC power supply current of DC12 V supplied from the SW power supply circuit  50  to the main unit  2 , from a DC terminal  55  through the DC power supply transmission cable  4  and the DC input terminal  25  through the separating circuit  51 . Thus, the AC adapter  3  can charge the portable telephone with music reproducing function  6  through the connection terminal for charging stand  13 . 
     Incidentally, the main unit  2  receives the DC current from the AC adapter  3  through the DC power supply transmission cable  4 . On the other hand, the main unit  2  superimposes the music data SMD 1  on the DC current by the superimposing circuit  46  and transmits the music data SMD 1  to the AC adapter  3 . 
     In this case, as shown in  FIG. 6 , the main unit  2  transmits the music data SMD 1  through the DC power supply transmission cable  4 . Then, the AC adapter  3  inputs the music data SMD 1  transmitted through the DC power supply transmission cable  4  to the separating circuit  51 . 
     As described above, the AC adapter  3  is adapted to be able to receive the music data SMD 1  from the main unit  2  through the DC power supply transmission cable  4 . Thus, the AC adapter  3  separates the DC current and the music data SMD 1  by the separating circuit  51 , extracts only the music data SMD 1  and then sends the music data SMD 1  to the receiver  53 . 
     The receiver  53  demodulates the music data SMD 1  to restore the original music data MD 1 . The receiver  53  filters only a low-frequency component from the restored music data MD 1  to obtain the low range components MD 1 L of the music data MD 1  and sends the low range components MD 1 L to the class D amplifier  54 . The class D amplifier  54  amplifies the low range components MD 1 L and outputs a low-pitched sound in accordance with the low range components MD 1 L through the sub-woofer  33 . 
     Further, them an unit  2  performs the digital signal processing of the music data MD 1  reproduced and supplied from the portable telephone with music reproducing function  6  by the digital signal processor  43 . Then, the main unit  2  stores the thus processed music data MD 1  in a memory  47 . Thus, the main unit  2  can read the music data MD 1  from the memory  47  and output the sound according to the music data MD 1  from the left speaker  14  and the right speaker  15  through the class D amplifier  44 . 
     As described above, the main unit  2  can store many types of music data MD 1  in the memory  47 , reproduce the music data MD 1 , and output the music data MD 1  from the left speaker  14  and the right speaker  15 . Accordingly, even if the portable telephone with music reproducing function  6  is not connected, the main unit  2  itself can become a reproducing means and sound output means of the music data MD 1 . 
     Further, in the main unit  2 , the MPU  40  can detect a call existed in the portable telephone with music reproducing function  6  through the connection terminal for charging stand  13 . When the call in the portable telephone with music reproducing function  6  is detected while the music data MD 1  is reproduced and outputted from the left speaker  14  and the right speaker  15 , the main unit  2  is adapted to forcibly lower the sound volume level of the music data MD 1  through the digital signal processor  43  and output the calling sound from the left speaker  14  and the right speaker  15 . 
     Then, the main unit  2  is shifted to a hands-free state. After the incoming sound is outputted, the main unit  2  outputs sound of the other party from the left speaker  14  and the right speaker  15 . 
     (5) Operation and Effect 
     In the configuration described above, the acoustic system  1  outputs the mid-high range audio sound corresponding to the music data MD 1  reproduced by the portable telephone with music reproducing function  6  connected through the connection terminal for charging stand  13  from the left speaker  14  and right speaker  15 . The main unit  2  can output the low range audio sound corresponding to the music data MD 1  from the sub-woofer  33  of the AC adapter  3 . Accordingly, the low range audio sound which cannot be outputted only from the left speaker  14  and the right speaker  15  can be sufficiently covered by the sub-woofer  33 . 
     At this time, the acoustic system  1  can provide a richly expressive acoustic environment from the low range audio sound to the mid-high range audio sound without allowing a user to feel the presence of the sub-woofer  33  in appearance by arranging the main unit  2  mounting the left speaker  14  and the right speaker  15  on the table, for example, and installing the AC adapter  3  concealed in the sub-woofer  33  within the body  31  under a table. 
     Particularly, since the AC adapter  3  is adapted to output only the low range audio sound with no directivity from the sub-woofer  33 , the sub-woofer  33  can be concealed in the body  31 . Thus, the AC adapter  3  can allow the user to feel as if the sound from the low range to the mid-high range is outputted to the user only from the left speaker  14  and the right speaker  15  of the main unit  2 . 
     Incidentally, the AC adapter  3  can output only the sound of the low range component MD 1 L tuned by the port  35 . Further, the sub-woofer  33  is entirely covered by the body  31 . Accordingly, even if the mid-high range audio sound which cannot be filtered by the digital filtering is outputted, the mid-high range audio sound hardly leak from the body  31  to the outside. Only the low range audio sound can be outputted certainly by the mechanical filtering configuration. 
     Furthermore, the acoustic system  1  not only can supply the DC power DC from the AC adapter  3  to the main unit  2  by the DC power supply transmission cable  4  of the power supply line, but also can transmit the music data SMD 1  from the main unit  2  to the AC adapter  3 . Thus, the entire configuration of the acoustic system  1  can be simplified without necessity of providing the power supply line for the DC power DC and the signal line for the music data SMD 1 . 
     Accordingly, the acoustic system  1  can connect the main unit  2  to the AC adapter  3  by the general-purpose DC power supply transmission cable  4 . Therefore, a general AC adapter  3  (not shown) which does not carry the sub-woofer  33  can be connected by the DC power supply transmission cable  4  without using the AC adapter  3  according to one embodiment of the present invention. Thus, the usability of the acoustic system  1  can be further improved. 
     According to the configuration described above, the acoustic system  1  can output the mid-high range audio sound by the left speaker  14  and the right speaker  15  of the main unit  2  as well as the low range audio sound by the sub-woofer  33  built in the main unit  2  in concealing manner. Accordingly, the richly expressive listening environment can be provided without increasing the size of the main unit  2  by the sub-woofer  33  and without letting the user aware of the presence of the sub-woofer  33 . 
     (6) Other Embodiments 
     Incidentally, in the above-mentioned embodiments, there has been described the case that the sound based on the music signal reproduced by the portable telephone with music reproducing function  6  is outputted from the left speaker  14  and the right speaker  15  of the main unit  2  and the sub-woofer  33  of the AC adapter  3 . However, the present invention is not limited to this. The sound of a music signal or a radio program reproduced by the electronic apparatus, such as a semiconductor memory built-in type or hard disk-built in type portable audio player, a Personal Digital Assistant (PDA), etc., may be outputted from the left speaker  14  and the right speaker  15  of the main unit  2  and the sub-woofer  33  of the AC adapter  3 . 
     Further, in the above-mentioned embodiments, there has been described the case that the left speaker  14  and the right speaker  15  are provided for the main unit  2  in the acoustic system  1  of 2.1 channel and the one sub-woofer  33  is provided in the AC adapter  3 . However, the present invention is not limited to this. Two or more speakers may be provided for the main unit  2 , or a plurality of sub-woofers may be provided in the AC adapter  3 . 
     Furthermore, in the above-mentioned embodiments, there has been described the case that the main unit  2  having the charging stand  12  is used as a main unit. However, the present invention is not limited to this. As the main unit, an electronic apparatus, such as a notebook-sized personal computer, a PDA or the like may be used. Even in this case, in addition to the sound outputted from the speaker of the notebook-sized personal computer or the PDA, the low range audio sound can be outputted by the sub-woofer  33  of the AC adapter  3 . Accordingly, the richly expressive acoustic space in which the low range audio sound is sufficiently outputted, can be provided. 
     Moreover, in the above-mentioned embodiments, there has been described the case that as the power adapter, the AC adapter  3  is used. However, the present invention is not limited to this. As the power adapter, a DC/DC adapter for supplying the DC power of the predetermined voltage level may be used for the main unit  2 . 
     Further, in the above-mentioned embodiments, there has been described the case that the main unit  2  connects the external electronic apparatus through the line input terminal  26  and the music signal is inputted from the external electronic apparatus. However, the present invention is not limited to this. The music signal may be inputted through a memory stick (Registered Trademark of Sony Corporation) attachable to/detachable from the main unit  2  or a Universal Serial Bus (USB) memory. 
     The acoustic system of the present invention can be applied to a component system which uses, for example, a small speaker in which the low range audio sound is often insufficient. 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.