Patent Publication Number: US-2005131561-A1

Title: Information handling system including docking station with digital audio capability

Description:
BACKGROUND  
      The disclosures herein relate generally to information handling systems (IHS&#39;s) and more particularly to audio solutions for IHS&#39;s with docking stations.  
      As the value and use of information continue to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system (IHS) generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.  
      Many modern portable IHS&#39;s such as laptop computers, notebook computers and personal digital assistants (PDA&#39;s) couple to a docking station to provide a user with a full size keyboard, display, mouse and loudspeakers when the portable IHS is operated from a fixed location. Docking stations are known that included an analog sound output to which analog sound signals are routed from the portable IHS through a docking interface between the IHS and the docking station. Unfortunately, such analog audio solutions are susceptible to noise from the processor and power supply along long cable runs. Another significant problem with analog audio in docking stations is presented by ground loops resulting from differences in potential between the portable IHS and the docking station. Although with substantial effort and troubleshooting skill it is possible to minimize such noise and ground loops in a particular IHS design, when changes are made to design a successor model for the IHS, the noise and ground loop problems often must be analyzed and solved anew.  
      To provide a more noise tolerant interface between the portable IHS and docking station, digital audio signals have been transmitted from the portable IHS across the docking interface to the docking station. Implementations of the Audio CODEC 1997 (AC&#39;97) standard such as AC-Link and the Intel Azalia interface do not address all of the intricacies of a docking implementation. Substantial amounts of software customization are still necessary to insure proper audio performance across the docking interface. 12S is another digital audio standard; however, 12S is not supported in may of today&#39;s integrated AC&#39;97 audio CODECs. Universal Serial Bus (USB) is another interface digital standard in current use. However, conventional operating systems do not allow seamless interaction between USB and AC&#39;97 audio devices. For this reason, USB is not a good candidate for usage in a docking environment which is to transport digital audio.  
      What is needed is a way to transmit digital audio across a docking interface between a portable device and a docking station which provides noise immunity while lending itself to being readily adapted to many different versions of a particular IHS model.  
     SUMMARY  
      Accordingly, in one embodiment, a method of operating an information handling system including a portable portion and a docking station is disclosed. The method includes generating, by the portable portion, a digital audio signal conforming to the S/PDIF standard. The method also includes sending the digital audio signal across a docking interface between the portable portion and a docking station. The method further includes converting the digital audio signal to an analog audio signal and amplifying the analog audio signal.  
      In another embodiment, an information handling system (IHS) is disclosed which includes a processor and memory coupled to the processor. The IHS also includes glue logic coupled to the processor for facilitating connection of the processor to other devices. The IHS further includes an audio coder decoder coupled to the glue logic. The audio coder decoder includes a S/PDIF digital audio output. The IHS still further includes a docking station having a digital audio receiver coupled to the S/PDIF digital audio output for converting S/PDIF digital audio to analog audio.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a block diagram of the disclosed information handling system. 
    
    
     DETAILED DESCRIPTION  
       FIG. 1  is a block diagram of the disclosed information handling system (IHS)  100 . For purposes of this disclosure, an information handling system (IHS) may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, an information handling system may be a personal computer, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The information handling system may include random access memory (RAM), one or more processing resources such as a central processing unit (CPU) or hardware or software control logic, ROM, and/or other types of nonvolatile memory. Additional components of the information handling system may include one or more disk drives, one or more network ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The information handling system may also include one or more buses operable to transmit communications between the various hardware components.  
      IHS  100  includes a portable system  200  such as a notebook, laptop, PDA or other handheld system and a docking station  300  as shown in  FIG. 1 . Portable system  200  includes a processor  205  such as an Intel Pentium series processor or one of many other processors currently available. An Intel Hub Architecture (IHA) chipset  210  provides IHS  100  with glue-logic that connects processor  205  to other components of IHS  100 . Chipset  210  carries out graphics/memory controller hub functions and I/O functions. More specifically, chipset  215  acts as a host controller which communicates with a graphics controller  215  coupled thereto. Graphics controller  215  is coupled to a display  220 . Chipset  210  also acts as a controller for main memory  225  which is coupled thereto. Chipset  210  further acts as an I/O controller hub (ICH) which performs I/O functions. Input devices  230  such as a mouse, keyboard, and tablet, are also coupled to chipset  210  at the option of the user. An expansion bus  235 , such as a Peripheral Component Interconnect (PCI) bus, PCI Express bus, SATA bus or other bus is coupled to chipset  210  as shown to enable IHS  100  to be connected to other devices which provide IHS  100  with additional functionality. A universal serial bus (USB)  240  or other I/O bus is coupled to chipset  210  to facilitate the connection of peripheral devices to IHS  100 . System basic input-output system (BIOS)  245  is coupled to chipset  210  as shown. BIOS  245  is stored in nonvolatile memory such as CMOS or FLASH memory. A network interface controller (NIC)  250  is coupled to chipset  210  to facilitate connection of system  100  to other information handling systems. A media drive controller  255  is coupled to chipset  210  so that devices such as media drive  260  can be connected to chipset  210  and processor  205 . Devices that can be coupled to media drive controller  260  include CD-ROM drives, DVD drives, hard disk drives and other fixed or removable media drives. IHS  100  includes an operating system which is stored on media drive  260 . Typical operating systems which can be stored on media drive  260  include Microsoft Windows XP, Microsoft Windows 2000 and the Linux operating systems. (Microsoft and Windows are trademarks of Microsoft Corporation.)  
      Portable system  200  includes an audio CODEC  265  coupled to chipset  210 . Audio CODEC  265  is compatible with the Audio Codec 1997 (AC97) standard. CODEC  265  includes a microphone input  270  and a CD input  275 . CODEC  265  also includes an analog output  280  which is coupled to the input on an audio amplifier  285 . Amplifier  285  is coupled to both left and right loudspeakers  290  and to a headphone jack  295 . CODEC  265  includes a S/PDIF digital output  297 . S/PDIF is an acronym meaning Sony-Philips Digital Interface, a standard protocol for transmitting digital information. S/PDIF output  297  is coupled to one pin of a multi-pin docking connector  305 A which includes multiple pins for connecting circuits and devices within portable system  200  to circuits and devices within docking station  300 .  
      Docking station  300  includes a multi-pin docking connector  305 B which mates with multi-pin docking connector  305 A of portable system  200 . The S/PDIF output  297  of CODEC  265  is coupled across docking connector  305 A,  305 B to a port of a S/PDIF receiver  310 . S/PDIF receiver  310  includes a digital to analog (D/A) converter which is coupled to a high power amplifier  315  which drives a LINE OUT output  320  as shown. The LINE OUT output  320  is the main audio output of docking station  300  and can be used to drive high power speakers much larger than the relatively small speakers typically included in portable systems  200 . Audio amplifier  315  is a multiple channel amplifier having a number of channels equal to the number of audio channels included in the particular S/PDIF digital signal transmitted from CODEC  265  to S/PDIF receiver  310 . Receiver  310  converts the digital audio signal bit stream that it receives into the original multiple analog audio signal channels, for example, left and right analog audio signal channels. Receiver  310  includes a digital to analog converter to accomplish this conversion back to analog. Docking station  300  includes a power amplifier  325  which is coupled to an output of receiver  310  to amplify a bass audio signal received therefrom. Docking station  300  is configured in an enclosure  332  which exhibits a substantially closed volume  335  with the exception of a subwoofer loudspeaker  320  which projects sound through an aperture  340  in enclosure  332 . Subwoofer loudspeaker  330  acoustically cooperates with the substantially closed volume  335  to enhance bass audio response. Docking station  300  includes a keyboard connector  345  to enable a keyboard to be coupled from docking station  300  through connector  305 A- 305 B to portable system  200 . Docking station  300  also includes a display or video connector  350  to enable a standalone display to be coupled to portable system  200  via docking station  300 . Docking station  300  further includes a media drive connector  355 , for example a DVD or CD drive connector, to enable an external media drive to be connected to portable system  200  via docking station  300 .  
      Although illustrative embodiments have been shown and described, a wide range of modification, change and substitution is contemplated in the foregoing disclosure and in some instances, some features of an embodiment may be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in manner consistent with the scope of the embodiments disclosed herein.