Abstract:
An Out Door Unit (ODU) provides the capability to aggregate signals received from more than one satellite before providing the signals to a multi-switch for selection 0by an integrated decoder-receiver (IRD). The signals from a first satellite are relocated by means of a local oscillator and multiplier to frequencies of unused channels in the signals from a second satellite. The relocated signals from the first satellite are then summed with the unused channels in the signals from the second satellite.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is related to co-pending and commonly-assigned application Ser. No. 09/676,065 filed on same date herewith, by Kesse C. Ho, and entitled “LOW NOISE BLOCK DOWN CONVERTER ADAPTER WITH BUILT-IN MULTI-SWITCH FOR A SATELLITE DISH ANTENNA,” which application is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention. 
     The present invention relates generally to a satellite receiver antenna, and in particular, to the aggregated distribution of multiple satellite transponder signals in a satellite dish antenna. 
     2. Description of the Related Art. 
     DIRECTV® can broadcast video programming signals from transponders on three satellites in three different orbital slots located at 101 West Longitude (WL), 119 WL, and 110 WL, also known as Sat A, Sat B, and Sat C, respectively. The FCC (Federal Communications Commission) has allocated to DIRECTV® transponders  1 - 32  on 101 WL, transponders  22 - 32  on 119 WL, and transponders  28 ,  30 ,  32  on 110 WL. 
     In the prior art, a four-input multi-switch (Multi-SW) was used to select among the signals received from the transponders on 101 WL and 119 WL, wherein there are two different signal polarizations (Left and Right) output by each associated low noise block down converters with feed (LNBFs) for each orbital slot and each of the different signal polarizations is a separate input to the multi-switch. However, to accommodate the additional orbital slot located at 110 WL would require a greater number of inputs on the multi-switch. 
     In a conventional signal acquisition and distribution method, five cables would be used to receive signals from the transponders in the three orbital slots using three associated LNBFs, wherein two of the LNBFs have dual outputs to the multi-switch (one for each of the two signal polarizations for 101 WL and 119 WL) and one of the LNBFs has a single output to the multi-switch (one for the single signal polarization for 110 WL). Further, a conventional signal acquisition and distribution method would require the use of an addressing-capable multi-switch and an integrated receiver-decoder (IRD) capable of providing a compatible addressing signal to the multi-switch to select and decode the five different inputs. This adds a level of complexity to these two devices, increases their manufacturing and installation costs, and lowers system reliability. 
     Thus, there is a need in the art for a method wherein signals from multiple satellites can be received and distributed using fewer sets of cables. There is also a need for a method that simplifies polarization switching requirements for the LNBFs and IRD. 
     SUMMARY OF THE INVENTION 
     The present invention describes an antenna or Out Door Unit (ODU) that provides the capability to aggregate signals received from more than one satellite before providing the signals to a multi-switch for selection by an integrated decoder-receiver (IRD). The signals from a first satellite are relocated by means of a local oscillator and multiplier to frequencies of unused channels in the signals from a second satellite. The relocated signals from the first satellite are then summed with the unused channels in the signals from the second satellite. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring now to the drawings in which like reference numbers represent corresponding parts throughout: 
     FIG. 1 is a diagram illustrating an overview of a multiple satellite video distribution system according to the preferred embodiment of the present invention; 
     FIG. 2 illustrates an antenna configured according to the preferred embodiment of the present invention; 
     FIG. 3 illustrates the structure of an LNBF/Multi-SW Adapter according to the preferred embodiment of the present invention; and 
     FIG. 4 illustrates the operation of a multi-switch and combiner according to the preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In the following description, reference is made to the accompanying drawings which form a part hereof, and which show, by way of illustration, several embodiments of the present invention. It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. 
     FIG. 1 is a diagram illustrating an overview of a multiple satellite video distribution system according to the preferred embodiment of the present invention. The system includes multiple satellites  100 A-C, uplink antenna  102 , and transmit station  104 . In the preferred embodiment, the three satellites  100 A-C are in three different orbital slots located at 101 West Longitude (WL)  100 A, 119 WL  100 B, and 110 WL  100 C, wherein the video programming signals  106 A-C are transmitted from transponders  1 - 32  on 101 WL  100 A, transponders  22 - 32  on 119 WL  100 B, and transponders  28 ,  30 , and  32  on 110 WL  100 C. The radio frequency (RF) signals  106 A-C are received at one or more downlink antennae  108 , which in the preferred embodiment comprise subscriber receiving station antennae  108 , also known as outdoor units (ODUs). Each downlink antennae  108  is coupled to one or more integrated receiver-decoders (IRDs)  110  for the reception and decoding of video programming signals  106 A-C. 
     FIG. 2 illustrates the subscriber antenna  108  as configured according to the preferred embodiment of the present invention. In the side view of FIG. 2, the antenna  108  has an 18″×24″ oval-shaped Ku-band reflecting surface that is supported by a mast  112 , wherein a minor axis (top to bottom) of the reflecting surface is narrower than its major axis (left to right). The antenna  108  curvature is due to the offset of one or more low noise block down converters with feed (LNBFs)  114 , which are used to receive signals reflected from the antenna  108 . In the preferred embodiment, a support bracket  116  positions an LNBF/Multi-SW Adapter  118  and multiple LNBFs  114  below the front and center of the antenna  108 , so that the LNBFs  114  do not block the incoming signals  106 A-C. Moreover, the support bracket  116  sets the focal distance-between the antenna  108  and the LNBFs  114 . 
     The LNBFs  114  comprise a first stage of electronic amplification for the subscriber receiving station. Each LNBF  114  down converts the 12.2-12.7 GHz signals  106 A-C received from the satellites  100 A-C to 950-1450 MHz signals required by a tuner/demodulator of the IRD  110 . The shape and curvature of the antenna  108  allows the antenna  108  to simultaneously direct energy into two or three proximately disposed LNBFs  114 . 
     In one embodiment, the orbital locations of the satellites  100 A-C are chosen so that the signals  106 A-C received from each satellite  100 A-C can be distinguished by the antenna  108 , but close enough so that signals  106 A-C can be received without physically slewing the axis of the antenna  108 . When the user selects program material broadcast by the satellites  100 A-C, the IRD  110  electrically switches LNBFs  114  to receive the broadcast signals  106 A-C from the satellites  100 A-C. This electrical switching occurs using a combiner and multi-switch within the LNBF/Multi-SW Adapter  118 . 
     FIG. 3 is an exploded view that illustrates the structure of the LNBF/Multi-SW Adapter  118  according to the preferred embodiment of the present invention. The LNBF/Multi-SW Adapter  118  is described in detail in co-pending and commonly-assigned application Ser. No. 09/676,065, filed on same date herewith, by Kesse C. Ho, and entitled “LOW NOISE BLOCK DOWN CONVERTER ADAPTER WITH BUILT-IN MULTI-SWITCH FOR A SATELLITE DISH ANTENNA,” which application is incorporated by reference herein. 
     The LNBF/Multi-SW Adapter  118  is a single plastic Y-shaped housing that incorporates a combiner and multi-switch (shown in FIG.  4 ), three ports  120 A-B for connection to three LNBFs  114 , and four outputs that comprise four cables  122  that exit from the rear of the Adapter  118  for connection to the IRDs  110 . 
     Two of the three ports  120 A and  120 C have two male ‘F’ connectors  124 A, B, D, and E, and one of the three ports  120 B has a single male ‘F’ connector  124 C. A dual output LNBF  114  is inserted into each of ports  120 A and  120 C (for 101 WL  100 A and 119 WL  100 B, respectively), while a single output LNBF  114  is inserted into port  120 B (for 110 WL  100 C). The female ‘F’ connectors  126  comprising output IF (intermediate frequency) terminals of each LNBF  114  simply plug into the male ‘F’ connectors  124  of the Adapter  118 . Of course, those skilled in the art will recognize that other embodiments could have different numbers of ports  120 , different configurations of connectors  124  and  126 , and support various types and numbers of LNBFs  114 . 
     The Adapter  118  mates to the support bracket  116 , although the Adapter  118  is shown separated from the support bracket  116  in FIG. 3 for the purposes of illustration. In this embodiment, the support bracket  116  comprises a hollow tube that carries the cables  122  to the rear of the antenna  108  for connection to the IRDs  110 . Only the coaxial cables  122  that connect to the IRD  110  exit from the support bracket  116  at the rear of the antenna  108 . 
     FIG. 4 illustrates the operation of a multi-switch  128  and combiner  130  according to the preferred embodiment of the present invention. In the preferred embodiment, the multi-switch  128  and combiner  130  are housed within the Adapter  118 , although other embodiments could mount these components in any location. 
     The 12.2˜12.7 GHz signals  106 A-C received from the satellites  100 A-C pass through a feed horn  132  of the LNBF  114  and are down converted by a local oscillator  134  and multiplier  136  in the LNBF  114  to the 950-1450 MHz signals required by a tuner/demodulator of the IRDs  110 . Left and right polarized signals  138  and  140  are output from the LNBFs  114 . 
     The local oscillator  134  and multiplier  136  in the LNBF  114  for 110 WL  100 C are used to relocate the channels for 110 WL  100 C for the purposes of the present invention. Specifically, the local oscillator  134  and multiplier  136  in the LNBF  114  for 110 WL  100 C relocate the three channels received from 110 WL  100 C into unused positions within the assigned 950˜1450 MHz spectrum of 119 WL  100 B (in one example, channels  28 ,  30 , and  32  are relocated to channels  8 ,  10 , and  12 ). The combiner  130  then masks the unused 119 WL  100 B channels and combines the relocated 110 WL  100 C channels with the assigned 950˜1450 MHz spectrum of 119 WL  100 B. Specifically, the combiner  130  sums the relocated channels from 110 WL  100 C with the channels received from 119 WL  100 B (in one example, relocated channels  8 ,  10 , and  12  from 110 WL  100 C are summed with channels  22 - 32  from 119 WL  100 B) within the assigned 950-1450 MHz spectrum. 
     Those skilled in the art will note that the channel assignments provided above are merely illustrative, and that any desired channel arrangement could be used by proper selection of the local oscillator  134  frequency. Moreover, those skilled in the art will recognize that channels from more than two signal polarizations could be relocated and aggregated using the present invention, with the use of additional or different combiners  130 , oscillators  134 , and multipliers  136 . 
     This summed output from the combiner  130  is then provided to single input  144  of the multi-switch  128 . The multi-switch  128  generally comprises a cross-bar switch, wherein any of the four cables  122  can be connected to any of the four inputs  144  from the three LNBFs  114 . The selection of which input  144  to connect to a desired cable  122  via the multi-switch  128  is controlled by a signal received on the coaxial cable  122  from the IRD  110 , in a manner well known in the art (e.g., an 18V, 13V, 18V/22 kHz, or 13V /22 kHz signal from the IRD  110  selects one of the four inputs  144  to the multi-switch  128 ). 
     Thus, the present invention provides the capability to aggregate the signals  106 B and  106 C received from satellites 119 WL  100 B and 110 WL  100 C before the multi-switch  128 , in order to decrease the number of inputs needed on the multi-switch  128 . Consequently, a four-input multi-switch  128  can be used to select among five different signals output from three different LNBFs  114  based on three different sets of signals  106 A-C received from transponders on three different satellites  100 A-C. Moreover, fewer sets of cables  122  are required and the polarization switching requirements for the LNBFs  114 , multi-switch  128 , and IRDs  110  are simplified, thereby resulting in significant savings in component and installation costs. 
     This concludes the description of the preferred embodiments of the present invention. The foregoing description of the preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. 
     It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto. The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.