Patent Publication Number: US-2011061081-A1

Title: Reflector apparatus for video home networks

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to video home networks, and more particularly, to a reflector apparatus that improves signal quality within video home networks. 
     2. Background Information 
     Video home networks are commonly used to distribute media content to various rooms of a home or other dwelling. The infrastructure of such networks typically includes a transmission medium such as coaxial cable coupled to various electronic devices (e.g., televisions, set-top boxes, etc.) via a plurality of signal splitters. As a given network grows in size to is accommodate additional devices, the number of levels of signal splitting may also increase.  FIG. 1  is a diagram of an exemplary video home network having three levels of signal splitting. 
     As indicated in  FIG. 1 , media content (e.g., audio/video) signals provided from a point-of-entry (POE) can be distributed to various set-top boxes (STB 1 -STB 8 ) via coaxial cable (RG- 59 ) and various signal splitters (Splitter  1 -Splitter  7 ). Within the video home network of  FIG. 1 , media content signals may also be transmitted from one set-top box to another. For example, consider the scenario in which a source set-top box (STB 1 ) transmits media content signals to a receiving set-top box (STB 8 ). In this scenario, the signal level at the input of the receiving set-top box (STB 8 ) is based primarily on the sum of two signals, namely a first signal that passes directly from the source set-top box (STB 1 ) to the receiving set-top box (STB 8 ) via the applicable signal splitters (Splitters  1 - 4  and  7 ), and a second signal that is reflected from the point-of-entry (POE). Depending on the level of isolation between the respective outputs of the applicable signal splitters and level of the signal reflected from the point-of-entry (POE), three situations can arise: (i) the first signal has a greater signal level than the second signal, (ii) the second signal has a greater signal level than the first signal, and (iii) the first and second signals have approximately the same signal level. In  FIG. 1 , any given pair of set-top boxes can operate as source/receiving pair. Regardless of which set-top boxes make up the pair, there will always be two s relevant signals, as described above. In these cases, the quality of service within the network (i.e., signal level at receiving device) is adversely affected due to a multi-path problem when the first and second signals have approximately the same signal level (i.e., situation (iii) above). Accordingly, there is a need to provide an apparatus which addresses this multi-path problem in video home networks. 
     Another issue affecting the quality of service within video home networks relates to the performance of the signal splitters themselves. One challenge of existing networks is to combat signal loss due to the presence of is signal splitters. In general, the better performance a signal splitter provides (i.e., good isolation, good impedance match, etc.) the more difficult it is to provide reliable video networking. The isolation between outputs of signal splitters currently available on market may vary in range, for example, from 10 to 35 dB. Signal splitters with 10 dB isolation between outputs are generally considered to provide poor performance (i.e., poor isolation, poor impedance match, etc.). However, such signal splitters generally provide a favorable level of signal attenuation within a network. Conversely, better isolation between outputs of a signal splitter introduces more signal loss within a network. Accordingly, there is a need to provide an apparatus which is immune to the performance of signal splitters in a video home network. 
     The invention described herein addresses the aforementioned and/or other problems, and provides a reflector apparatus which improves signal quality within video home networks. 
     SUMMARY OF THE INVENTION 
     In accordance with an aspect of the present invention, an apparatus is disclosed. According to an exemplary embodiment, the apparatus comprises means such as a first terminal for receiving a broadcast signal from a signal source, and means such as a second terminal for outputting the broadcast signal to a plurality of external devices coupled to the apparatus via a signal splitter. The apparatus further comprises means such as circuitry for receiving a network signal from a first one of the plurality of external devices and controlling a gain of the network signal responsive to a control signal from a second one of the plurality of external devices to thereby generate a reflected network signal. The reflected network signal is output to the second one of the plurality of external devices. 
     In accordance with another aspect of the present invention, a method is disclosed. According to an exemplary embodiment, the method comprises receiving via a first terminal of an apparatus, a broadcast signal from a signal source; outputting via a second terminal of the apparatus, the broadcast signal to a plurality of external devices coupled to the apparatus via a signal splitter; receiving, via the second terminal of the apparatus, a network signal from a first one of the plurality of external devices; controlling a gain of the network signal responsive to a control signal from a second one of the plurality of external devices to thereby generate a reflected network signal; and outputting, via the second terminal of the apparatus, the reflected network signal to the second one of the plurality of external devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a diagram of an exemplary video home network having three levels of signal splitting; 
         FIG. 2  is a diagram of a video home network having a reflector apparatus according to an exemplary embodiment of the present invention; 
         FIG. 3  is a diagram of the reflector apparatus of  FIG. 2  according to an exemplary embodiment of the present invention; 
         FIG. 4  is a diagram of the reflector apparatus of  FIG. 2  according to another exemplary embodiment of the present invention; and 
         FIG. 5  is a flowchart illustrating a method according to an exemplary embodiment of the present invention. 
     
    
    
     The exemplifications set out herein illustrate preferred embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, and more particularly to  FIG. 2 , a diagram of a video home network having a reflector apparatus  30  according to an exemplary embodiment of the present invention is shown. The video home network of  FIG. 2  comprises a point-of-entry (POE)  10 , a reflector  35 , a reflection level control block  40 , a signal splitter  50 , and a plurality of external devices  60  and  70 . For purposes of example and explanation, only two external devices  60  and  70  are shown in  FIG. 2 , and these devices are represented as set-top boxes (STB 1  and STB 2 ). However, in practice, the number of external devices included in the video home network may be greater than two (requiring additional signal splitters), and such devices may be embodied as other types of electronic devices (e.g., television, DVD player, etc.). Also in  FIG. 2 , the elements of the video home network are shown as being coupled via RG- 59  coaxial cable. In practice, however, other types of transmission mediums may also be used. 
     In a first mode of operation, reflector  35  receives a broadcast signal from POE  10  and outputs the broadcast signal for distribution to external devices  60  and  70  via signal splitter  50 . According to an exemplary embodiment, the broadcast signal may be a satellite signal in a frequency band of 950 to 2150 MHz. However, other types of broadcast signals (e.g., cable, terrestrial, etc.) in other frequency bands may also be provided in accordance with the principles of the present invention. 
     In a second mode of operation (which may be performed simultaneously with the first mode of operation), one of the external devices  60  or  70  may transmit a network signal including audio and/or video content to the other external device  60  or  70  upon request. In such cases, reflector  35  is operative to generate a reflected version of the network signal responsive to a control signal. For purposes of example and explanation,  FIG. 2  shows this control signal being provided from reflection level control block  40 . However, according to an exemplary embodiment, this control signal is actually provided from the external device  60  or  70  that requests and receives the network signal from the other external device  60  or  70 . Further details regarding reflector  35  and the aforementioned first and second modes of operation will hereinafter be provided. 
     Referring now to  FIG. 3 , a diagram indicating particular detail of reflector  35  of  FIG. 2  according to an exemplary embodiment of the present invention is shown. As indicated in  FIG. 3 , reflector apparatus  30  comprises a directional coupler  12 , a diplexer  14 , an amplifier  16 , a signal multiplier  18 , an oscillator  20 , a band pass filter (BPF)  22 , a variable gain amplifier  24 , and a controller  26 . It is noted that signal multiplier  18  and oscillator  20  are optional elements and may be included as a matter of design choice if reflector apparatus  30  needs to provide a frequency conversion function. 
     In the first mode of operation, diplexer  14  receives a broadcast signal (e.g., satellite signal) from POE  10  via a first terminal A of reflector apparatus  30 . In practice, POE  10  may represent a frequency translation module (FTM), which is generally known in the art. Alternatively, POE  10  may simply represent the entry point of a transmission medium (e.g., coaxial cable) within a home or other dwelling. The received broadcast signal is passed from diplexer  14  to directional coupler  12  and output from reflector apparatus  30  at a second terminal B. The broadcast signal is then distributed over the cable network, split via signal splitter  50  and provided to external devices  60  and  70  for processing and output (see  FIG. 2 ). According to an exemplary embodiment, diplexer  14  is configured to simply pass the relatively high frequency (e.g., 950 to 2150 MHz) broadcast signal to directional coupler  12  for output onto the network. In this manner, reflector apparatus  30  simply operates as a pass-though for the received broadcast signal during the first mode of operation and does not generate a reflected signal. 
     In the second mode of operation (which may be performed simultaneously with the first mode of operation), a user at one of the external devices  60  or  70  may desire to receive a network signal comprised of audio and/or video content from the other external device  60  or  70  (see  FIG. 2 ). Such content may for example be stored on a recording medium (not shown in FIGS.) associated with one of the external devices  60  or  70 . As an example, assume a user at external device  60  (STB  1 ) wants to receive a network signal representing desired audio and/or video content from external device  70  (STB  2 ). To initiate this operation, the user provides an input to external device  60  (e.g., responsive to an on-screen menu, etc.) which causes external device  60  to generate and output a request signal for such content. This request signal, which may be the same frequency as the requested network signal, passes through the network and is ultimately received by external device  70 . External device  70  outputs the network signal comprised of the desired audio and/or video content responsive to the request signal. The network signal passes through signal splitter  50  and is received by reflector apparatus  30  at second terminal B. Directional coupler  12  passes the received network signal to diplexer  14  which in turn passes the network signal to amplifier  16 . 
     According to an exemplary embodiment, the network signal exhibits a frequency that is different (i.e., higher or lower) than the aforementioned broadcast signal. In this manner, frequency selective diplexer  14  is able to detect the network signal for passage to amplifier  16 . Amplifier  16  amplifies the network signal and passes the resulting amplified network signal to signal multiplier  18  which may frequency convert the network signal to a higher or lower frequency. As previously indicated herein, signal multiplier  18  and oscillator  20  are optional elements of reflector apparatus  30 . The output of frequency multiplier  18  (if included) passes to BPF  22  which filters the network signal to generate a filtered network signal. This filtered network signal is then passed to variable gain amplifier  24 . 
     In addition to the request signal, external device  60  also generates and outputs a control signal that is operated upon by reflector apparatus  30  to control the gain of the network signal provided by external device  70 . According to an exemplary embodiment, the control signal is received by reflector apparatus  30  at second terminal B and passes through directional is coupler  12  to diplexer  14 . Diplexer  14  receives the control signal from directional coupler  12  and passes it to controller  26 . The control signal indicates a particular level of gain control to be applied to the network signal. In response to the control signal, controller  26  generates an output signal that is provided to variable gain amplifier  24  which amplifies the network signal responsive to the output signal to thereby generate a gain controlled (i.e., reflected) network signal. This reflected network signal is then passed to directional coupler  12  which outputs the reflected network signal over the network at second terminal B. The reflected network signal passes through signal splitter  50  and is received by external device  70  for processing and output. External device  70  may also adaptively generate and output the aforementioned control signal based on the received signal level of the reflected network signal and/or user input so as to optimize the signal level of the reflected network signal and provide a desired quality of service. In this manner, controller  26  may cause variable gain amplifier  24  to vary its level of amplification over time while the network signal is being received by reflector apparatus  30 . 
     If reflector apparatus  30  includes the frequency conversion functionality provided by the optional signal multiplier  18  and oscillator  20 , external device  60  may also output a control signal that causes controller  26  to control the operation of signal multiplier  18  and oscillator  20  and thereby frequency convert the network signal. Alternatively, if reflector apparatus  30  does not include the frequency conversion functionality provided by the optional signal multiplier  18  and oscillator  20 , both the network signal and the reflected network signal will exhibit the same frequency. 
     to  FIG. 4  is a diagram of reflector apparatus  30  of  FIG. 2  according to another exemplary embodiment of the present invention. Reflector apparatus  30  of  FIG. 4  is substantially similar to reflector apparatus  30  of  FIG. 3 , except for the inclusion of an additional diplexer  28 . With both embodiments (i.e.,  FIGS. 3 and 4 ), the diplexers are operative to discriminate on the basis of is frequency among broadcast signals (which are simply passed from POE  10  to devices  60  and  70 ), request and network signals (which are processed by amplifier  16 , BPF  22 , and variable gain amplifier  24 , and possibly signal multiplier  18 ), and control signals (which are passed to controller  26  for control purposes). The control signals may be for example exhibit a lower frequency than the broadcast signals and the request and network signals. 
     By generating the reflected network signal in the aforementioned manner, reflector apparatus  30  of both embodiments are able to create a differential between the signal levels of the (non-reflected) network signal and the reflected network signal and thereby prevent the multi-path problem discussed previously herein. The architecture of reflector apparatus  30  is also desirable from a cost standpoint, and its functionality as described herein provides immunity from the performance of signal splitters in a video home network. 
     Referring to  FIG. 5 , a flowchart  500  illustrating a method using embodiments of the present invention is shown. For purposes of example and explanation, the steps of  FIG. 5  will be described with reference to the video home network of  FIG. 2  and reflector apparatus  30  of  FIG. 3 . The steps of  FIG. 5  are exemplary only, and are not intended to limit the present invention in any manner. 
     At step  510 , reflector apparatus  30  receives a broadcast signal from POE  10  via first terminal A. According to an exemplary embodiment, the broadcast signal may be a satellite signal in a frequency band of 950 to 2150 MHz, although other types of broadcast signals (e.g., cable, terrestrial, etc.) in other frequency bands may also be received in accordance with the principles of the present invention. 
     At step  520 , reflector apparatus  30  outputs the received broadcast signal via second terminal B. According to an exemplary embodiment, the received broadcast signal is passed from diplexer  14  to directional coupler  12  and output from reflector apparatus  30  at a second terminal B. The broadcast signal is then distributed over the cable network, split via signal splitter  50  and provided to external devices  60  and  70  for processing and output. Steps  510  and  520  are part of the first mode of operation previously described herein. 
     At step  530 , reflector apparatus  30  receives a network signal via second terminal B from one of the external devices  60  or  70 . According to an exemplary embodiment, the network signal is transmitted to reflector apparatus  30  from one of the external devices  60  or  70  responsive to a request signal sent from the other external device  60  or  70 . The network signal passes through signal splitter  50  and is received by reflector apparatus  30  at second terminal B. 
     At step  540 , reflector apparatus  30  generates a reflected network signal using the received network signal. According to an exemplary embodiment, directional coupler  12  passes the received network signal to diplexer  14  which in turn passes the network signal to amplifier  16 . As previously indicated herein, the network signal exhibits a frequency that is different than the aforementioned broadcast signal and control signal received by reflector apparatus  30 . Amplifier  16  amplifies the network signal and passes the resulting amplified network signal to signal multiplier  18  which may frequency convert the network signal to a higher or lower frequency. As previously indicated herein, signal multiplier  18  and oscillator  20  are optional elements of reflector apparatus  30 . The output of frequency multiplier  18  (if included) passes to BPF  22  which filters the network signal to generate a filtered network signal. The filtered network signal is then passed to variable gain amplifier  24  which amplifies the filtered network signal responsive to an output signal provided from controller  26  to thereby generate the reflected network signal. As previously indicated herein, the output signal from controller  26  is generated responsive to a control signal provided from the external device  60  or  70  that requests and receives the reflected network signal. Also previously indicated herein, the external device  60  or  70  that requests and receives the reflected network signal may also adaptively generate and output the aforementioned control signal based on the received signal level of the reflected network signal and/or user input so as to optimize the signal level of the reflected network signal and provide a desired quality of service. In this manner, controller  24  may cause variable gain amplifier  24  to vary its level of amplification over time while the network signal is being received by reflector apparatus  30 . 
     At step  550 , reflector apparatus  30  outputs the reflected network signal via second terminal B to the other external device  60  or  70 . According to an exemplary embodiment, the reflected network signal output from variable gain amplifier  24  passes through directional coupler  12  and is output onto the network at second terminal B for subsequent receipt by the external device  60  or  70  that requested the same. Steps  530  to  550  are part of the second mode of operation previously described herein, which may be performed simultaneously with the previously described first mode of operation represented by steps  510  and  520 . 
     As described herein, the present invention provides a reflector apparatus that improves signal quality within video home networks. While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.