Abstract:
Preferred embodiments of a radio-frequency and electrical power distribution duct are implemented with high-definition multimedia interface HDMI receptacles to deliver high-bandwidth digital signals to multiple signal receivers.

Description:
RELATED APPLICATION 
     This application claims benefit of U.S. Patent Application No. 61/510,379, filed Jul. 21, 2011. 
    
    
     TECHNICAL FIELD 
     The field of this disclosure relates to digital signal delivery systems, and, in particular, to a system for delivering a digital signal to multiple output devices such as television sets (e.g., high-definition television sets). 
     BACKGROUND INFORMATION 
     U.S. Pat. Nos. 4,307,435 and 4,962,447 describe radio-frequency and power distribution ducts to deliver signals and power to a plurality of receivers (e.g., television sets). A distribution duct includes longitudinal compartments containing power receptacles and radio-frequency signal receptacles. Specifically, the radio-frequency signal receptacles correspond to coaxial tees. One threaded shank of each coaxial tee extends through a hole in a cover of the distribution duct, and coaxial cables are connected to the two other threaded shanks of the coaxial tees to electrically connect them together to form a signal distribution system. The signal distribution system is connected to a source (e.g., an antenna) that supplies a signal to the system, and receivers are connected to the threaded shanks extending through the holes of the cover to deliver the signal to the receivers. One particularly useful application of these distribution ducts is the retail sale of television sets in which the television sets are connected to a single signal source and placed side-by-side to be viewed by customers. 
     Digital signal sources (e.g., digital signal broadcasters, digital versatile disc (DVD) players, Blu-ray disc players, digital set-top boxes) and digital receivers (e.g., high-definition television sets) have become increasingly popular over the last several years. Digital signal sources and digital receivers often include high-definition multimedia interface (HDMI) receptacles that facilitate communication of high-bandwidth digital signals representing one or both of high-quality video and high-quality audio. The applicant has recognized a need for a digital signal distribution system for delivering a high-bandwidth digital signal to multiple digital receivers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of a digital signal and power distribution duct according to one embodiment. 
         FIG. 2  is a partly exploded isometric view of the digital signal and power distribution duct of  FIG. 1 . 
         FIG. 3  is an enlarged sectional view of the digital signal and power distribution duct taken along the lines  3 - 3  of  FIG. 1 . 
         FIG. 4  is an isometric view of an HDMI tap device, according to one embodiment, used in the digital signal and power distribution duct of  FIG. 1 . 
         FIG. 5  is a sectional top view of the HDMI tap device of  FIG. 4 . 
         FIG. 6  is a fragmentary sectional top view of the digital signal and power distribution duct of  FIG. 1  showing the HDMI tap device of  FIG. 4  provided in a compartment of the duct and connected to signal lines. 
         FIGS. 7-11  are fragmentary sectional top views of the digital signal and power distribution duct of  FIG. 1  showing alternative HDMI tap device configurations. 
         FIG. 12  is a sectional top view of the digital signal and power distribution duct of  FIG. 1  shown in relation to a digital signal distribution system that includes two HDMI tap devices in a daisy chain configuration. 
         FIG. 13  is a sectional top view of an HDMI coupler, according to one embodiment, used in the digital signal distribution system of  FIG. 12 . 
         FIG. 14  is an isometric view of two of the digital signal and power distribution ducts of  FIG. 1  daisy chained together. 
         FIG. 15  is a top plan view of multiple HDMI tap devices hard-wired together to form a daisy chain. 
         FIG. 16  is an isometric view of two digital signal and power distribution ducts of  FIG. 1  that abut each other and are connected together. 
         FIG. 17A  is an isometric view showing the cover of a distribution duct that holds four power receptacles and six HDMI tap devices. 
         FIG. 17B  is a diagram showing use of an extension printed circuit board to provide cableless electrical series interconnection of the six HDMI tap devices of  FIG. 17A . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  is an isometric view and  FIG. 2  is a partly exploded isometric view of a digital signal and power distribution duct  5 , according to one embodiment, for delivering power and digital signals to multiple digital output devices such as high-definition television sets. Duct  5  includes one or more power receptacles  10  and HDMI tap devices  17  (two power receptacles  10  and two HDMI tap devices  17  are shown in  FIGS. 1 and 2 ) disposed between side walls  20 ,  25 . In one non-limiting example, duct  5  is 8 feet in length and power receptacles  10  and HDMI tap devices  17  are provided every 12 or 16 inches along the length of duct  5 . A bottom wall  30  joins side walls  20 ,  25  to form a generally U-shaped structure. A longitudinal partition  35  depends from bottom wall  30  to divide the U-shaped structure into a longitudinal power compartment  40  and a longitudinal digital signal compartment  45 . Inwardly extending flanges  50 ,  55  extend from respective side walls  20 ,  25  toward longitudinal partition  35 . Inwardly extending flanges  50 ,  55  support one or more power receptacles  10  as further explained with reference to  FIG. 3 . 
       FIG. 3  is a cross-sectional end view of duct  5 . Each of the power receptacles  10  includes a body portion  60  having a width slightly less than a spacing between flanges  50 ,  55 . Power receptacles  10  also include first and second outwardly extending spring members  65 ,  70  and an outer face  75  that has a width greater than the width of body portion  60  so that outer face  75  overlies the edges of flanges  50 ,  55 . As power receptacles  10  are inserted into compartment  40 , spring members  65 ,  70  compress to permit outer face  75  to seat against flanges  50 ,  55 , and then spring members  65 ,  70  expand within compartment  40  to hold outer face  75  against flanges  50 ,  55 . 
     Duct  5  includes a removable cover  80  that has longitudinally spaced-apart openings  85  that are sized to surround outer face  75  of power receptacles  10 . Instead of power receptacles  10  having spring members  65 ,  70  to hold power receptacles  10  in duct  5 , power receptacles  10  may be adhered to cover  80  using an adhesive or secured to it using rivets, screws, nuts and bolts or any other known fastener. Longitudinal partition  35  includes a depending bottom wall  86  and a side wall  87 . Walls  86 ,  87 , together with longitudinal partition  35 , form a longitudinal channel  88  that has a width that is appropriate to engage a suitable machine screw  89 . Optional serrations  90  may be formed in longitudinal partition  35  and wall  87  with a pitch matching that of the threads of screw  89 . Cover  80  includes a plurality of openings  90  to accommodate multiple machine screws, such as screw  89 . Rivets that engage longitudinal channel  88  may also be used to attach cover  80  to duct  5 . 
     Power receptacles  10  may be placed and moved anywhere along compartment  40 . Accordingly, the positions of power receptacles  10  may be adjusted to coincide with the locations of openings  85  in cover  80 . Power receptacles  10  are spatially aligned with openings  85  so that power receptacles  10  may be mated with power plugs of external power supply lines connected to output devices to thereby power the output devices. Power receptacles  10  are wired in parallel in a conventional manner prior to installation in compartment  40 . Conventional electrical conductors (e.g., power supply lines) for wiring the power receptacles  10  in parallel are not shown. Power receptacles  10  provide AC power connections for output devices. An end wall  92  of duct  5  includes a knock-out opening  93  to accommodate installation of a suitable power connector (e.g., power plug, power receptacle) or a power cord  94  that is hard-wired to one of receptacles  10 . Alternatively, knock-out opening  93  for the power connector or power cord  94  may be provided in cover  80 . Moreover, power cord  94  may be connected to a resettable fuse (not shown) positioned in power compartment  40 , and the resettable fuse may have a reset button that is accessible through an opening in cover  80 . End wall  92  also includes a second knock-out opening  95  to accommodate installation of an HDMI connector (e.g., HDMI receptacle connector) or an HDMI signal line  100  (e.g., HDMI cable) that is directly connected to one of HDMI tap devices  17 . Alternatively, knock-out opening  95  for the HDMI connector or HDMI signal line  100  may be provided in cover  80 . 
       FIG. 3  shows one of HDMI tap devices  17  provided in longitudinal digital signal compartment  45  and secured to cover  80 . HDMI tap devices  17  may be secured to cover  80  using any known securing mechanism and method including spring members similar to spring members  65 ,  70  of power receptacles  10 . In one example, HDMI tap devices  17  includes flanges  110  that facilitate fastening of HDMI tap devices  17  to cover  80 . For example, flanges  110  may be adhered to cover  80  using an adhesive or secured to it using rivets, screws, nuts and bolts or any other known fastener. Flanges  110  may be secured to an inner face  111  of cover  80 , as shown in  FIG. 3 , or an outer face  112  of cover  80 . Each of HDMI tap devices  17  includes a tap receptacle output face  115  that faces cover  80  and is spatially aligned with one of multiple longitudinally spaced-apart openings  120  in cover  80  to facilitate access to HDMI tap device  17 . Tap output receptacle output face  115  may sit flush with outer face  112  of cover  80  as shown in  FIG. 3 . Alternatively, tap output receptacle output face  115  may extend outward beyond outer face  112  of cover  80  or may be recessed inward from outer face  112 . 
     HDMI tap devices  17  may be configured in various ways. In general, HDMI tap devices  17  include an input and at least two outputs, one of which is a tap output receptacle (i.e., female) connector configured to receive a plug of a standard HDMI signal line that is located external from compartment  45 .  FIG. 4  is an isometric view of an HDMI tap device  170 , according to one embodiment. HDMI tap device  170  includes a housing  175  that has a “T” shaped profile and contains a printed circuit board (PCB)  180  as shown in  FIG. 5 . Three HDMI receptacle connectors  185 ,  190 ,  195  are mounted on PCB  180  to form an in-line T-tap configuration for HDMI tap device  170 . Specifically, connectors  185 ,  190  face in opposite directions along a common axis (i.e., connectors  185 ,  190  are in-line), and connector  195  faces in a direction that is transverse to the directions in which connectors  185 ,  190  face to form a “T” shaped HDMI connector configuration. Connectors  185 ,  190 ,  195  are aligned with three openings  196 ,  197 ,  198  provided along side walls  199  of housing  175 . The in-line T-tap configuration of HDMI tap device  170  enables connector  195  to face and be spatially aligned with one of openings  120  in cover  80  of duct  5  and connectors  185 ,  190  to face in directions along the longitudinal length of compartment  45  of duct  5  to thereby facilitate ease in connection of receptacle connectors  185 ,  190  to plug connectors of HDMI cables in compartment  45 . In one example, connector  185  is an input receptacle connector, connector  190  is an output receptacle connector, and connector  195  is a tap output receptacle connector. 
     As shown in  FIG. 4 , connectors  185 ,  190 ,  195  include pins  200  configured in a standard HDMI pin layout (e.g., connector type A layout, connector type B layout, connector type C layout). Pins  200  of connectors  185 ,  190 ,  195  are electrically connected to signal traces of PCB  180 . Moreover, the signal traces of PCB  180  are configured to electrically connect pins  200  of connector  185  to pins  200  of connectors  190 ,  195  to form a digital signal tap in which a signal transmitted to connector  185  is further transmitted to connectors  190 ,  195 . 
       FIG. 6  is a fragmentary sectional top view of duct  5  showing HDMI tap device  170  provided in compartment  45 . An input signal line  205  runs along compartment  45  and includes a plug  210  that mates with connector  185 , which serves as an input receptacle connector. An output signal line  215  also runs along compartment  45  and includes a plug  220  that mates with connector  190 , which serves as an output receptacle connector. Connector  195 , which serves as a tap output receptacle connector, is aligned with one of openings  120  in cover  80  and is mated with a plug  225  of a signal supply line  230  that is external to duct  5 . Plugs  210 ,  220 ,  225  each include pins that spatially align with and electrically connect to pins  200  of receptacle connectors  185 ,  190 ,  195 . In the configuration shown in  FIG. 6 , a digital signal is supplied from input signal line  205  to receptacle connector  185 , from receptacle connector  185  to receptacle connector  190 , and from receptacle connector  190  to output signal line  215 . The digital signal is also supplied from receptacle connector  185  to receptacle connector  195 , and from receptacle connector  195  to signal supply line  230 . 
     Skilled persons will recognize that the configuration of HDMI tap device  170  is one possible configuration for HDMI tap devices  17  and that other configuration are possible. For example,  FIGS. 7-11  are partial cross-sectional top plan views of duct  5  showing various other possible configurations for HDMI tap devices  17 . Configurations other than those shown in  FIGS. 7-11  are possible for HDMI tap device  17 .  FIG. 7  shows an HDMI T-tap device  270  that has a “T” shaped profile similar to device  170 . However, instead of having three receptacle connectors like device  170 , device  270  includes one receptacle connector  295  that connects to signal supply line  230 . An input signal line  300  and an output signal line  305  are hard-wired to a PCB of device  270 , and input signal line  300  is electrically connected to output signal line  305  and receptacle connector  295 . Multiple devices  270  may be hard-wired together. For example,  FIG. 15  shows six devices  270  hard-wired together via signal lines  306  to form a hard-wired HDMI tap device daisy chain. 
       FIG. 8  shows an HDMI Y-tap device  370  that has a “Y” shaped profile. Device  370  includes three receptacle connectors  385 ,  390 ,  395  that are the same as connectors  185 ,  190 ,  195  of device  170 . Alternatively, device  370  may be configured like device  270  in which connectors  385 ,  390  are replaced with input signal line  300  and output signal line  305  that are hard-wired to a PCB of device  370 . 
       FIG. 9  shows an HDMI tap device  470  that includes an input receptacle connector  485  and an output receptacle connector  490  provided along one side wall  492  of device  470  and a tap output receptacle connector  495  provided along a second side wall  497  opposite side wall  492 . Alternatively, device  470  may be configured like device  270  in which connectors  485 ,  490  are replaced with input signal line  300  and output signal line  305  that are hard-wired to a PCB of device  470 . 
       FIG. 10  shows an HDMI T-tap device  570  that is identical to device  170  except that a housing  575  of device  570  has a rectangular shaped profile instead of a “T” shaped profile. Alternatively, device  570  may be configured like device  270  in which connectors  185 ,  190  are replaced with input signal line  300  and output signal line  305  that are hard-wired to a PCB of device  570 . 
       FIG. 11  shows an HDMI T-tap device  670  that includes HDMI receptacle connectors  685 ,  690 ,  695  that are electrically connected to a central tap unit  700  via intermediary signal lines  705 ,  710 ,  715  that are hard-wired to connectors  685 ,  690 ,  695  and a PCB contained in central tap unit  700 . Signal lines  705 ,  710 ,  715  may be flexible to enable connectors  685 ,  690 ,  695  to be maneuvered to various positions. 
     In some of the configurations of HDMI tap devices  17  in which HDMI tap devices include input and output receptacle connectors, the tap output receptacle connector is positioned to face a different direction from the direction(s) that the input and output receptacle connectors face. Accordingly, the input and output receptacle connectors of HDMI tap devices  17  may be conveniently and easily connected to signal lines contained in compartment  45  of duct  5 , while only the tap output receptacle connectors of HDMI tap devices  17  are visible through openings  120  of cover  80 . In other configurations of HDMI tap devices  17  in which HDMI tap devices  17  include hardwired input and output signal lines  300 ,  305 , the tap output receptacle connector is positioned to face a different direction than the direction(s) along which input and output signal lines  300 ,  305  run. 
       FIG. 12  is a sectional top view of duct  5  shown in relation to a digital signal distribution system  800  that includes two HDMI tap devices  17  and other components. A digital signal source  805  (e.g., a digital signal media source) is connected to HDMI signal line  100 . Signal line  100  is connected to an HDMI receptacle connector  815  that is positioned along end wall  92  of duct  5 . In one embodiment, HDMI receptacle connector  815  is a receptacle coupler that includes two in-line receptacle connectors  820 ,  825 , as shown in  FIG. 13 , that are electrically connected to each other. In this embodiment, a plug of signal line  100  is mated with one of receptacles  820 ,  825 , and a plug of input signal line  205  is connected to the other one of receptacles  820 ,  825 . In an alternative embodiment, connector  815  includes one receptacle that is connected to signal line  100 , and input signal line  205  is hard-wired to connector  815 . Alternatively, signal line  100  may pass through knock-out opening  95  in end wall  92  and be directly connected or hard-wired to a first one of HDMI tap devices  17 . In another alternative embodiment, signal line  100  may pass through-knock out opening  95  in end wall  92  and be connected or hard-wired to a signal amplifier (e.g., signal boosting device). In another alternative embodiment, signal line  100  may be a CAT 5, CAT 6, coax, fiber optic, or other type of cable and may connect to an adapter (e.g., an HDMI over CAT 5E/CAT6 receiver, HDMI over coax receiver, HDMI over fiber optic receiver) that configures (e.g., converts) the signal traveling along signal line  100  to an HDMI useable signal. 
     Input signal line  205  is connected to an input receptacle connector  826  of a first one of HDMI tap devices  17 . Output signal line  215  is connected between an output receptacle connector  827  of the first one of HDMI tap devices  17  and an input receptacle connector  828  of a second one of HDMI tap devices  17  to electrically connect HDMI tap devices  17  together. Optionally, a signal line  830  may be connected between an output receptacle connector  831  of the second one of HDMI tap devices  17  and an HDMI receptacle connector  835  provided along a second end wall  840  of duct  5 . HDMI receptacle connector  835  may be a receptacle coupler as shown in  FIG. 13  or may be hard-wired to signal line  830  and include one receptacle that faces outward from second end wall  840 . In an alternative embodiment, second end wall  840  does not include HDMI receptacle connector  835  and signal line  830  passes through a knock-out opening provided in second end wall  840 . 
     Tap output receptacle connectors  845 ,  850  of HDMI tap devices  17  are aligned with and face one of openings  120  of cover  80 . A signal supply line  855  is connected between tap output receptacle connector  845  and a digital output device  860 , and a signal supply line  865  is connected between tap output receptacle connector  850  and a digital output device  870 . 
     In operation, digital signal source  805  transmits a digital signal to the first one of HDMI tap devices  17  through signal line  100 , connector  815  and input signal line  205 . The first one of HDMI tap devices  17  supplies the digital signal to the second one of HDMI tap devices  17  through output signal line  215  and to output device  860  through supply line  855 . The second one of HDMI tap devices  17  supplies the digital signal to output device  870 . In this manner, both of output devices  860 ,  870  produce a representation of the digital signal (e.g., display images represented in the digital signal). 
     Duct  5  may be connected to other digital signal and power distribution ducts to increase the number of output devices connected to digital signal distribution system  800 .  FIG. 14  shows one embodiment in which duct  5  is electrically connected to a second duct  905 . Power receptacles  10  of duct  5  receive electrical power from an external power source  906 , shown in  FIG. 1 , via power cord  94 . A power cord  907  is connected between duct  5  and duct  905  to deliver power to power receptacles  910  of duct  905 . Power cord  907  may pass thorough knock-out openings in end walls  840 ,  911  of ducts  5 ,  905  and be hard-wired to power receptacles  10 ,  910 , or end walls  840 ,  911  may include power connectors (e.g., power receptacles, power plugs) to which power cord  907  connects to enable easy connection and disconnection of power between ducts  5 ,  905 . External power supply lines connected to output devices are electrically connected to power receptacles  10 ,  910  to thereby deliver power to the output devices. 
     Tap output receptacle connectors  845 ,  850  of duct  5  receive digital signals from digital signal source  805  via signal line  100 . A signal line  912  is connected between duct  5  and duct  905  to deliver the digital signals to tap output receptacle connectors  913 ,  914  of duct  905 . As described above, end wall  840  may include connector  835  to which signal line  912  connects. Alternatively, signal line  912  may pass through a knock-out opening in end wall  840  and be connected or hard-wired to the HDMI tap device that includes receptacle connector  850 . End wall  911  of duct  905  may include an HDMI receptacle connector (e.g., a receptacle coupler as shown in  FIG. 13 ) to which signal line  912  connects or a knock-out opening through which signal line  912  passes through to connect to the HDMI tap device that includes tap output receptacle connector  913 . 
     In an alternative embodiment shown in  FIG. 16 , ducts  5 ,  905  may abut each other instead of having power cord  907  and signal line  912  provided between them. In this embodiment, power receptacles  10 ,  910  may be hard-wired together and HDMI tap devices including tap output receptacle connectors  850 ,  913  may be hard-wired together. Alternatively, ducts  5 ,  905  may include matable (plug and receptacle) power connectors and matable (plug and receptacle) HDMI connectors provided along end walls  840 ,  911 , and the matable power and HDMI connectors electrically connect together when ducts  5 ,  905  abut each other. 
     Skilled persons will recognize that one or more other digital signal and power distribution ducts may be connected (e.g., daisy chained) to ducts  5 ,  905 . In one embodiment, a signal boosting device  915  (e.g., an HDMI signal extender, a repeater), as shown in  FIG. 14 , may be connected in series between ducts  5 ,  905  to boost the digital signal supplied to the HDMI tap devices of duct  905 . Signal boosting device  915  enables the digital signal to maintain an acceptable signal level over a longer distance than a system without signal boosting device  915 . Accordingly, signal boosting device  915  may be used to increase the number of ducts daisy chained to duct  5 . In one embodiment, one or both of ducts  5 ,  905  have an integrated signal boosting device provided in digital signal compartment  45  to boost the digital signal. An integrated signal boosting device may be used in the configuration shown in  FIG. 16 , for example. In another embodiment, one or more of the signal lines (e.g., signal lines  100 ,  205 ,  215 ,  830 ,  855 ,  865 ,  912 ) that supply the digital signal are active cables that include signal-enhancement electronics embedded in the housing of the signal lines that boost the digital signal. 
     The digital signal may be supplied over various types of cables that enable the digital signal to be transmitted a longer distance than the distance provided by a typical HDMI cable. For example, a CAT 5, CAT 6, coax, fiber optic, or other cable system may be used to transmit the signal to one or more HDMI tap devices  17 . For example, a transmitter (e.g., an extender) may be connected between an HDMI signal source and a CAT 5, CAT 6, coax, fiber optic, or other type of cable that enables an HDMI signal to be transmitted over the cable. A receiver is connected between the CAT 5, CAT 6, coax, fiber optic, or other type of cable and one or more HDMI tap devices  17  to condition the signal traveling along the cable for reception by HDMI tap devices  17 . The transmitter and receiver may incorporate boosters and equalization electronics to improve the quality of the digital signal. One or more of the transmitter and receiver may be incorporated in ducts  5 ,  905  (e.g., provided in or on the housing of ducts  5 ,  905 ) or may be stand-alone units. 
       FIG. 17A  shows a cover  80 ′ for the U-shaped structure of distribution duct  5 . Cover  80 ′ has along its length (preferably about 4 ft. (1.22 m)) six spaced-apart square openings  85  and four spaced-apart rectangular openings  120 . Each square opening  85  is sized to surround outer face  75  of a power receptacle  10  placed in power compartment  40  ( FIG. 2 ). Each rectangular opening  120  receives tap output receptacle connector  195  of an HDMI tap device  170  placed in digital compartment  45  ( FIG. 2 ). Gain control knobs  940  are each connected to a signal boosting device  915  ( FIG. 14 ) installed in digital signal compartment  45  to provide for adjustable digital signal strength. 
       FIG. 17B  shows an embodiment in which HDMI output and input receptacle connectors  190 ,  185  of next adjacent HDMI tap devices  170  are interconnected in electrical series by an extension printed circuit board (PCB)  942 , thereby eliminating cable interconnections. Each extension PCB  942  has signal traces that, at their ends, terminate in HDMI receptacle connectors that are matable to their associated HDMI tap device connectors. Corresponding pins  200  ( FIG. 4 ) configured in standard HDMI layout of HDMI receptacle connectors  185 ,  190  are electrically connected by associated signal traces of extension PCB  942 .  FIG. 17B  shows that each left-side HDMI receptacle connector of PCB  942  is mated with an output receptacle connector  190  and each right-side HDMI receptacle connector of PCB  942  is mated with an input receptacle connector  185 . Input receptacle connector  185  of the left-most HDMI tap device  170  and output receptacle connector  190  of the right-most HDMI tap device  170  can be connected by coaxial cables to, respectively, receive input and deliver output digital signals. 
     It will be obvious to skilled persons that many changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. The scope of the invention should, therefore, be determined only by the following claims.