EP2822199A1

EP2822199A1 - Low noise block (LNB) with optical output

Info

Publication number: EP2822199A1
Application number: EP14186759.8A
Authority: EP
Inventors: Gary Stafford
Original assignee: Global Invacom Ltd
Current assignee: Global Invacom Ltd
Priority date: 2006-02-22
Filing date: 2007-02-22
Publication date: 2015-01-07
Also published as: EP1987611A2; WO2007096617A2; WO2007096617A3

Abstract

The invention relates to a low noise block (LNB) for receiving data which is transmitted thereto via one or more satellite transmission systems and an antenna, the data being converted to an optical signal for transfer in an optical format to one or more premises. The LNB includes an integrated IF optical converter which includes waveguide probes (249) which split the received data into vertical and horizontal polarization paths which lead to an IF diplexer (213; 243', 243") and in turn a laser modulator (26; 215) to change the format of the data received into a single optical signal output (28) from the LNB. Digital Audio Broadcast (DAB) system and/or Digital terrestrial television (DTT) can be combined at the LNB and converted into an optical format to be carried as part of the single optical signal output from the LNB.

Description

The present invention relates to the reception of broadcast data signals and a network to allow the distribution of the received data signals such as those required to generate a television or radio programme to one or more decoding locations at which the data can be decoded for presentation to users for viewing and/or listening.
The distribution of received data is achieved in several known systems, one being by receiving the broadcast data at a Low Noise Block (LNB) at a suitable satellite antenna and the subsequent distribution of the data from the antenna to one or more decoding locations has been achieved in a number of ways based on one of organic design and development. Other systems , including a terrestrial antenna to receive digital terrestrial television broadcast data signals and an antenna to receive digital audio broadcast (DAB) broadcast data signals.
In general, short-term solutions have been developed to solve distribution problems of this data as they have occurred. The result of this is that there are many different systems available to route received data signals to receiver apparatus for decoding at different locations within the same or different premises, from a single or multiple antennas such as single or multiple DBS satellite antenna. The growth in requirement has been carried out in small discrete steps and so far more complex systems than are necessary have been developed. Further developments to carry an ever growing bandwidth, i.e increasing number of television and radio channels, to more locations will be increasingly costly, complex and require the use of apparatus which is specialised and costly when implemented on a large scale commercial basis.
This problem is especially relevant where television service providers or broadcasters are trying to develop networks to support more than one decoding means also known as a data receiver referred to as set top boxes (STB), for decoding the data in a home or in a building including a number of homes. The system providers would prefer not to have to continually upgrade a network each time a new decoding location or receiver is added to the original basic installation.
The problem is also particularly relevant in buildings with blocks of apartments with multiple dwelling units (MDU). Current systems use coaxial cable distribution from 4 separate IF outputs from a shared satellite antenna to a set of electrical switch boxes which then allow the selective splitting and connection to individual dwellings. A significant amount of high performance RF hardware is required and the current approach has some significant limitations and is not easily scalable.
The limitations of the current systems include that the installation of multiple coaxial cables is expensive and restrictive and the attenuation which occurs on coaxial cable puts design constraints on the possible lengths of the cable connections. The ability to upgrade the system is limited as more coaxial cables and larger switch or splitter blocks would be required to add new services. Also, an increasing number of each home having multiple receivers at different locations therein require multiple cable feeds and switch blocks to be provided.
The switches are required in the coaxial cable distribution system because it is not practical to multiplex the four output IF signals (upper and lower band for both data frequency polarisations) from the satellite dish LNB (low noise block) onto a single coaxial cable for feeding direct to each dwelling. This is because the resultant bandwidth of about 5GHz would require a much more expensive coaxial cable and additional electronic line amplifiers would be required to overcome losses of the data. However, the conventional switch or splitter blocks are bulky, expensive and need to be joined or cascaded together due to the fact that typically only 4 splits of an incoming signal can be made by any given splitter block.
A further problem area is the increasing number of television and radio channels which are required to be distributed in an MDU environment. Previously, systems could be used based on a single CT100 coax cable approach, as this has been possible due to the fact that a very restricted number of channels had to be distributed on a single polarization and these have typically been frequency stacked onto the single cable.
The planned expansion in the number of channels means that there is a significant increase in the data required for those channels to be generated and also, as a result, an increase in the data which needs to be distributed. The number of channels has or will go beyond the practical bandwidth capacity of a single cable and there are also problems with the physical space available within the cable ducts in many MDU buildings.
It is known to provide optical fibre based distribution equipment for received satellite data aimed at providing niche solutions typically when it is necessary to locate the antenna some distance from the dwelling to avoid a "shadow". These existing, optical fibre based, satellite distribution systems are high cost and have been developed from technology developed for defence or high-end professional applications rather than consumer electronics and typically use uses four optical fibre cables, one pair for each LNB high or low frequency band and a further pair for each polarization. These systems are complex and high cost as they require four optical transmitters per network which are typically the highest cost part of the system. In addition four optical receivers are required per outlet. It is hence not practical to use this type of system for a relatively low cost consumer network.
Another approach is to provide a system which moves the initial channel selection tuner from the receiver to the LNB. This removes the need for wide bandwidth distribution networks as, in effect, the LNB only outputs the channels required. The main limitation is the system's ability to only support four channels at any one time. This is a major problem, particularly when in practise the provision of data for four simultaneous channels is seen as a minimum and eight channels is the preferred requirement for the distribution of data channels to a range of premises or locations within a premises.
Another major issue is the power consumption of this system. In order to meet European directives, the stand-by power consumption of a STB is being driven down to a level of 1W. Some of the integrated circuit sets of the known system consume closer to 3W when configured to output four channels. This becomes more of a problem when it is considered that systems have to be able to receive continuous data from the satellite, even if the consumer is not watching TV, i.e when the system is in stand-by. This is because most broadcasters want to be able to send software updates to the receivers during these periods. As a result a system even in stand-by, will be consuming considerable power.
The aim of the present invention is to provide a system and apparatus which allows the transfer of data which is broadcast from a receiving location of said data, to one or more locations at which a decoding means, such as an STB, is located, in an efficient and economical manner.
In a first aspect of the invention, there is provided a broadcast data receiving system, said system incorporating at least one receiving means at a location, one or more decoding means, and cable connection means allowing the transfer of data between the receiving means and the locations of said decoding means, said at least one receiving means including a low noise block (LNB) and wherein said data is converted to a different mode for transfer along at least part of the cable connection and an interface is provided between the cable connection and said at least one or more decoding means, said interface including means to allow the data from the cable connection to be provided to the decoding means in a format or mode which can be processed by the decoding means and allow substantially all received data to be available at each of the decoding means to thereby allow all television and/or radio channels which can be generated from the data received to be available for user selection via the respective decoding means.
Preferably all of said data is available substantially simultaneously at each of said locations.
In one embodiment the cable connection means comprise one or more cables and at least one data splitting means connected thereto.
Typically the cable connecting means comprise a plurality of cables to allow the transmission of the received signals from the receiving means location to a plurality of decoding means locations.
In one embodiment, the receiving means is a satellite antenna to which the LNB is fitted. In one embodiment additional or alternative data receiving means are provided in the form of antenna for digital terrestrial television broadcast data and/or DAB data.
In on embodiment when data of more than one type is received at the receiving means, the data is combined and distributed along common cable connections.
In one embodiment the decoding means is a broadcast data receiver or set top box (STB).
In one embodiment the LNB for the satellite antenna includes a multiplexer for the received signals and typically a diplexer.
In one embodiment the decoding means are all provided within the same building but within different locations of the same building. In one embodiment the locations are within the same domestic premises or alternatively are located in different domestic premises such as, for example, in MDU's where there is a series of apartments owned and/or occupied by different people. In a yet further embodiment the decoding means may be provided in separate buildings.
In one embodiment, the interface allows the transfer of data to the decoding means from the cable connection in a form to allow the data to be decoded to allow television, radio and/or auxiliary services to be provided at each of the decoding means as selected by the user. Typically the decoding means are connected to a display screen and audio means such as for example a television set.
Thus, in accordance with the invention, the decoding means and the data supplied into the same can be provided in a conventional form. The transfer of the data signals representative of the received data intermediate the receiving location and the interface is in one embodiment in an RF mode or alternatively is provided in an optical mode, in which case there is provided an optical transmitter at the receiving means location and an optical receiver at or prior to the said interface.
In one embodiment the interface facilitates the transfer of optical data to an optical receiving decoding means or alternatively allows the conversion of the optical data back into a format in which the data was originally received.
In one embodiment, the interface located between the receiving and decoding means is located near to and typically at the premises at which the decoding means are located and allows the processing and subsequent supply of the received data to a single or a plurality of decoding means at that location in the correct format for use by the decoding means.
In one embodiment, the interface includes receiver and filter means for allowing the data from the satellite antenna receiving means via the cable connection to be allocated into four outlets one each for high and low horizontal polarity data and high and low vertical polarity data, thereby providing the data at the frequencies and polarities in the same manner as would be the case if the data had been received and transmitted to the decoding means in a conventional manner via the LNB directly via a single cable at the decoding means location. Thus the data can be dealt with in a normal manner by the decoding means.
In one embodiment, the interface also includes a dual output synthesiser.
In one embodiment the interface is incorporated in the decoding means.
In one embodiment, the receiving means and decoding means locations are provided in or on the same building with the building having a plurality of decoding means located therein.
In one embodiment, a plurality of decoding means locations are connected to a common receiving means location by the cable connections.
In one embodiment four decoding means can be connected to and supplied by an RF format connecting cable in accordance with the invention. Typically each decoding means can then be separately controlled by their respective users to request any of the television or radio channels or auxiliary information which can be generated from the data received at the receiving means simultaneously and without any significant impact caused by the connection or use of the other decoding means to the connecting cable at that time.
In an alternative embodiment the data is carried in an optical mode along one or more optical fibre connecting cables and typically the capacity of this cable and system is significantly greater in terms of the number of decoding means locations which can be supplied with the data from common receiving means.
In one embodiment a plurality of decoding means locations are connected to a common receiving means, and each of the decoding means receives data simultaneously from said receiving means.
Preferably each of the decoding means can be independently controlled by a respective user at that location to request any of the data received at the receiving means simultaneously. Thus each user can control, without the need to refer to or be impacted by the user selections made on other decoding means connected to the system at that time. Thus there is no limitation on the user operation of their particular decoding means connected to the system
In a further aspect of the invention, there is provided a broadcast data receiving system, said system incorporating a receiving means at a first location, and a plurality of data decoding means locations and cable connection means allowing the transfer of data between the receiving and data decoding means locations, said receiving means including at least one receiving means antenna and wherein the received data is converted into an optical mode and distributed to the decoding means locations via a network of optical fibre cable connections in that mode.
Typically at least one of the receiving means includes a satellite antenna and LNB.
Typically, the cable connecting means which connects the receiving means and decoding means locations, is one or more optical fibre cables and an interface is provided at said decoding means locations.
In one embodiment, a plurality of optical fibre cables are used as a connected network to connect the receiving means and decoding means, said cables connected via one or more optical data splitting means.
In one embodiment, the LNB includes, or is connected to, an intermediate frequency (IF) multiplexer and a laser transmitter to allow optical mode representations of the received data to be sent along the cable connection.
In one embodiment, at a location intermediate the receiving means and the data decoding means location the interface is provided, said interface allowing the transformation of the optical mode signals from the satellite antenna receiving means into the IF data signals format for subsequent supply to the data decoding means in a format to allow the data to be decoded to allow television, radio and/or auxiliary services to be provided via the decoding means.
In one embodiment the interface is provided to allow the IF data signals to be distributed to one data decoding means location. Alternatively the interface is located to allow data as it enters the premises to be in the IF mode and then distributed to a number of data decoding means in said premises.
Thus, in accordance with the invention, the receiving means and decoding means can be provided in a conventional form and the transfer of signals representative of the received data intermediate these two locations, is in an optical mode and, as the data is received by the LNB and received by the decoding means in the required format, this apparatus need not necessarily be changed from that conventionally being used.
In one embodiment, the LNB incorporates an integrated IF optical converter which includes waveguide probes which split the received data into vertical and horizontal polarisation paths which lead to an IF diplexer and in turn a laser modulator which transforms the IF data into an optical output and transmits the same.
In one embodiment, the interface located between the receiving and decoding means, is located at or adjacent to or within the location of each decoding means to allow for the transformation of the optical data into IF data for supply to a single or plurality of decoding means at that location.
In one embodiment, the interface includes an optical receiver, and filter means for allowing the IF data from the optical receiver to be placed into four outlets, namely, high and low horizontal polarity data and high and low vertical polarity data and then supplied by a conventional cable, such as a coaxial cable from the interface to the decoding means.
In one embodiment the interface can include a wall plate mounted on an internal wall of the premises and has one or more sockets to allow the connection of coaxial cable with the interface and hence allow the data to be supplied via the coaxial cable to the decoding means.
In one embodiment, at a location intermediate the receiving means LNB and the interface there are provided one or more splitters or junctions, said splitters allowing the splitting of the optical data from the connecting cable from the LNB, into a plurality of optical cable connectors thereby forming a distribution network with each of the cable connections carrying the same received data.
In one embodiment, each of the optical cables, can lead to one or more further optical splitters to allow the further splitting of the optical data signals. Typically, each of the optical cable connections leading from any of the splitters will pass to an interface at each of the decoding locations prior to connection to the decoding means at particular premises.
In one embodiment up to 96 decoding means locations can be supported by the system. In an alternative embodiment optical data signal boosting means may be provided and a larger number of locations can be supported.
The invention is of particular advantage for use in MDU buildings or in housing estates as it allows the efficient and practical splitting of data signals from a suite of receiving means antennas at a common location and the connection of a plurality of data decoding means in residential units or premises to the distribution system with a minimum of cabling being required. It also allows a significantly more simple LNB to be used for the satellite antenna receiving means as the conventional LNB output can be utilised and converted alone or in conjunction with data from other receiving means. The network can be provided to suit particular distribution requirements and may include some additional capacity therein to allow subsequent additional connections to be achieved without the need for reconfiguring the network.
A major advantage of the optical mode is that it is passive. Also the optical network is power efficient as no power amplifiers are required to overcome power loss in the connecting cable. The optical splitters do not consume power, in contrast to the conventional RF based MDU systems.
The optical laser transmitter unit is expected to consume in the order of 150mA at 2V and as the remaining operating circuits can all be powered from 2 or 3V this will enable the receiving means such as the LNB to be very power efficient.
Typically, the only consumer of power will be the interface which, in one embodiment, may be a wall plate unit mounted on an internal wall of each premises and which is used to facilitate and, if necessary, convert the optical signals back to standard IF bands suitable for the inputs of the decoding apparatus.
In one embodiment the interface is incorporated in the decoding means or the decoding means can be provided with an optical front end. The invention can therefore reduce the overall power consumption of an MDU network.
In one embodiment, the receiving location and data decoding locations are in the same building with the building having a number of premises located therein.
In one embodiment, a plurality of data decoding means locations are connected to a common receiving location.
In an alternative embodiment, there is provided a common receiving location which is remote from one or more decoding locations which may be provided in one or more separate buildings.
In one embodiment the connection cable includes a connector cable termination assembly to allow the optical cable to be connected to the LNB, said assembly incorporating a laser, an electronic driver, power feed for the LNB and the optical fibre.
In one embodiment, the assembly may also include an integrated circuit with a mode expansion and/or passive alignment capability.
In one embodiment, the free end of the connector includes a threaded portion to allow secure mechanical connection with the LNB.
In one aspect of the invention there is provided a system for the distribution of received digital data signals to a plurality of decoding means locations, via a cable connection network, wherein said system allows the carrying of data signals which are received via one or more differing transmission systems in the form of any or any combination of a satellite digital broadcast system, a Digital Audio Broadcast (DAB) system and/or Digital terrestrial television (DTT) system along common cables of at least part of said network in an optical mode.
In one embodiment the receiving means used can be as required to allow the reception of each of the data signal types and at the location of said receiving means the signals are combined, typically via the provision of suitable filter means and added via a diplexer to then be converted into an optical format, typically via at least one laser modulator unit. In this form therefore ,all of the received data is converted into an optical mode and passed along the one or more optical fibre cable connections of the distribution network to the one or more interfaces.
Typically at or in advance of each interface there is provided one or more splitting and processing means to allow the received optical mode data to typically firstly be converted back into the received data format, and then for the DAB, DTT and/or satellite received data to be split. Typically each format of data is then routed as required to the interface and/or decoding means apparatus as appropriate.
Typically for the satellite received data, the same will also be split into the high and low and different polarities as required.
In one embodiment, the data formats are routed to the interface for connection to one of a number of output sockets, to which the suitable apparatus can be connected to allow the particular data format to be processed.
Although, certainly in the short term it is preferred that the data can be reconverted from the optical mode back into a format which can be utilised by conventional decoding means, it should be noted that in an alternative embodiment the decoding means may be provided with means which allow the direct receipt and utilisation of the data in the optical mode. In this case the interface may still be provided to allow connection of the apparatus with the incoming data cables but the interface may not require the converting means and any conversion required can be performed within the decoding means.
Thus it should be appreciated that the invention can be used to allow the carrying of received data which is in a single format or in a number of different formats and which may have been received by multiple receiving means at the receiving location. The decision to provide a single or combined data distribution via the invention may be made based on a number of factors, such as, for example, whether there are any existing distribution systems in the buildings or between buildings, the condition and effectiveness of the same and/or whether the system is to be installed in a new build building or buildings.
The invention can be utilised as already stated with a single MDU building, with a single dwelling or to allow the distribution of data between a substantial number of buildings such as for example all or part of a housing estate. In each case the advantages obtained are significant in that, each decoding means user at each location can select from all of the received data at the receiving means at any time as all of the data is distributed via the connecting cables. Further more the ability to distribute data in the manner described allows only one set of receiving means to be required to supply multiple decoding means locations rather than the convention requirement of providing receiving equipment at each location. This reduces the need for relatively unsightly receiving apparatus to be provided at each decoding means location and for the same to be installed.
For larger capacity systems in accordance with the invention, the LNB may be required to be provided as a Universal Quattro LNB and an external satellite band , DTT and/or DAB stacker may be required to be provided prior to the data being converted into an optical mode.
In one embodiment, especially when there is provided a large network, the apparatus includes DTT, DVB receiving means including data filters and a Universal Quattro LNB and external satellite band, DTT, and DAB data frequency stacker.
In another embodiment, especially for buildings which include MDU's the LNB will include, for new build buildings an LNB with a DTV and DAB stacker. For premises which have already been built and which include an existing UHF distribution means then the system in accordance with the invention can be used for the data received via satellite and the existing UHF system is used for the DAB and/or DTT data distribution.
In a further aspect of the invention there is provided a broadcast data receiving system, said system incorporating a receiving means including a satellite antenna and LNB at a location, one or more decoding means, and cable connection means allowing the transfer of data between the receiving means and the locations of said decoding means, and an interface is provided between the cable connection and said at least one decoding means said interface including means to allow data from the cable connection in an optical mode, having been converted and transmitted along the cables in that mode by a laser modulator at or integral with the LNB, to be converted into a format usable by the data decoding means and all of the said received data is available at each of said decoding means locations to allow independent user selection of television, radio and/or auxiliary channels or services generated from said data, and said range that is available for selection at each of the decoding means substantially matches that which would be available via decoding means connected to the receiving means at the receiving means location.
Specific embodiments of the invention will now be described with reference to the accompanying drawings, wherein:-

Figure 1a-b illustrate embodiments of the invention in the form of an optical network in accordance with the current invention;
Figure 2 illustrates a circuit for an LNB in accordance with one embodiment of the invention;
Figure 3 illustrates a circuit for an interface in accordance with one embodiment of the invention;
Figures 4a-b illustrate a further embodiment of a network in accordance with the current invention;
Figure 5 illustrates a circuit for an LNB in accordance with the further embodiment of the invention;
Figure 6 illustrates a circuit for an interface in accordance with the further embodiment of the invention;
Figures 7a-c illustrate a further embodiment of the invention system;
Figures 8a-c illustrate a further embodiment of the invention; and
Figure 9 illustrates a further embodiment of the invention.

Referring firstly to Figure 1a, there is illustrated a network for the distribution of received broadcast data in accordance with one embodiment of the invention.
The system, in this case, is provided to supply a plurality of data decoding means locations, in this case within a building 4 with the data decoding locations being a series of flats or apartments within said building and one of which is shown.
In this case, each of the data decoding means locations, 2, is provided within the common building 4, although it will be appreciated, and as shown in Figure 1b that each of the data decoding means locations 2, can be provided in separate buildings.
In Figure 1a there is provided a 96-outlet network to allow 96 decoding means locations to be connected thereto and this is achieved using, firstly, a 4-way optical splitter 8 and a subsequent series of 8-way optical splitters 10 connected thereto in a manner which will be subsequently described. The system includes a broadcast data receiver in the form of a satellite antenna 12 which is linked to a low noise block (LNB) 14 which, in turn, is connected to the first optical splitter 8 via a single cable 16. The cable used throughout the network is optical fibre cable.
In both embodiments Figures 1a and b, the optical splitter 8 serves to split and reproduce the data signals in an optical format along subsequent optical fibre cables 18 and in Figure 1b these lead directly to each of the buildings 6. In Figure 1a, the cables 18 lead to a series of 8-way optical splitters 10 and from each splitter 10, there are provided eight optical cable connections 20. Each of these optical cable connections 20 can be connected to particular premises 2 and one example of this is shown in Figure 1a.
The optical cable connection 20' is connected to an interface 22 which in turn is connected to a decoding means 24 which may be provided to be connected to, or as an integral part of, a television set. It should also be appreciated that a plurality of decoding means (STB) may be provided at separate rooms within the same premises and reference to a decoding means hereonin refers to such an arrangement as well.
The data which is received at the antenna from the remote broadcast location is received in an IF form at receiver 12 and is transformed at the LNB into an optical form. The optical signals therefore pass along the single cable 16 and are split as required for a particular network and carried therealong until they reach an interface 22 which is provided at each of the premises 2. The interface 22 serves to transform the optical signals back to a data signal in a form which can then be decoded such that, for example, the decoding means which is used can be of a conventional form. Alternatively, the interface may be incorporated as part of the decoding means itself such that the decoding means may need to be altered in this embodiment.
Figure 2 illustrates one form of LNB in accordance with the invention and it will be seen that the LNB, at the front end 24 can be of conventional form comprising splitting means via waveguide probes for vertical polarisation and horizontal polarisation of the received signals. This then leads to an IF diplexer which in turn leads to a laser modulator 26. The laser modulator serves to transform the signals into an optical output 28 which is then fed to the single cable 16. In accordance with the present invention, all data for all channels can be carried on a single cable and therefore the prior art problems of relatively intensive apparatus requirement is overcome.
Figure 3 illustrates an interface in accordance with one embodiment of the invention and in this case, the interface is provided in the form of a wall plate module which effectively serves to de-stack and transform the data signals into a form which can be used by the decoder. The interface includes an optical receiver 30 for receiving the optical signal from the cable 20 and the optical receiver serves to transform the data, via filters 32 into the appropriate HL, HH, VL and VH data outputs 34 can be received and decoded by the decoding means.
A connector which may be used to connect the optical cable 16, 18 and/or 20 to apparatus can include power feed lines 36 to power the LNB, the optical fibre itself which is used to carry the optical signals and a laser device which allows the transfer of the signals from the optical fibre to the apparatus to which the same is connected. An electronic driver can be provided in connection with a connecting wire for insertion into a socket on the apparatus and threaded means can be provided to allow the mechanical location of the connector with the said apparatus.
If required, an integrated circuit can be provided with mode expansion and passive alignment for a pick and place assembly means.
Referring now to Figure 4, there is illustrated a further embodiment of a network for the distribution of received broadcast data in accordance with the invention.
The system, in this case, is provided to supply a plurality of decoding means 124 in a building 102, which in this case is a residential premises.
In Figure 4a there is provided a network for supplying data to four decoding means at premises 102 and this is achieved using, firstly, receiving means including a satellite antenna 112 which is linked to a low noise block (LNB) 114 and in turn to a splitter 108. These receiving means components are in turn connected to a series of decoding means 124 via an RF connecting cable 118 which connects the receiving means to the decoding means via an interface 122.
In Figure 4B an alternative version of this further embodiment is shown in which a plurality of buildings 102 are shown at separate locations, each having at least one decoding means 124 therein. In this case remote receiving means antenna 112 and LNB 114 are connected via cable 116 to splitter 108 and then via RF cables 118 to each of the buildings 102.
In both embodiments Figures 4a and 4b, splitter 108 serves to split and direct the received data signals into high and low, horizontal and vertical components. The cable connection 118 is connected to an interface 122 which in turn allows connection to one or more decoding means 124 which may be provided to be connected to, or as an integral part of a television set. Equally the interface may be provided as an integral part of the decoding means.
In the embodiment of Figure 4a a plurality of decoding means 124 are provided at separate rooms or premises within the same building and each of these are supplied with the full range of received data via the cable connection 118 and interface at the building.
The data which is received at the antenna 112 from the remote broadcast location is received in an IF form and can be transformed at the LNB into an RF form. The data signals therefore pass along the single cable 116 and are split by splitter 108 as required for a particular network and carried along one or more cables 118 until they reach an interface 122 which is provided at each of the receiving locations 102. The interface 122 serves to transform the RF signal to a data signal in a form which can then be decoded such that, for example, the decoding means 124 which are used can be of a conventional form. Alternatively, the interface may be incorporated as part of the decoding means itself.
Figure 5 illustrates one form of LNB in accordance with the invention and it will be seen that the LNB, at the front end 125 can be of conventional form comprising splitting means via waveguide probes 127 for vertical polarisation 129 and horizontal polarization 131 of the received data signals. This then leads to an IF diplexer 133 which in turn, via splitter 108, leads to the wideband RF cable connector 118. In accordance with the present invention, all data for all channels can be carried on the single RF broadband cable 118 and therefore the prior art problems of relatively intensive apparatus requirement is overcome.
Figure 6 illustrates an interface 122 in accordance with one embodiment of the invention and in this case, the interface is provided in the form of a wall plate module which effectively serves to de-stack and transform the received data signals from the cable 118 and into a form which can be used by the decoding means 124. The interface includes a receiver 130 for receiving the data signal from the cable connector 118 and the receiver serves to transform the data, via filters 132 into the appropriate Horizontal Low (HL), Horizontal High (HH), Vertical Low (VL) and Vertical High (VH) data outputs 134 which can be received and decoded by the decoding means 124.
Figures 7a-c illustrate a further embodiment of the invention which is found to be particularly useful when there is a desirability to allow the distribution of data which is received via more than one receiving means apparatus and/or to allow the distribution of data to a large number of decoding means locations such as for example a new build housing estate.
In accordance with this embodiment of the invention the new build housing estate decoding means locations are each of the houses and can all receive data from common receiving means apparatus. Furthermore various formats of data can be provided such as for example receiving means 201 for satellite transmitted data, a terrestrial TV antenna 203 for DTT data and an antenna 205 for DAB data can all be provided as shown in Figure 7a. The data from each of these receivers is processed, for example the DAB and DTT data passes through respective filters 207, 209, and the satellite antenna data is stacked in frequency at the LNB 211. The appropriately processed data is then configured via the 45MHz-5.45GHz diplexer 213 and passed as a combined data signal to an optical converter and laser modulator 215 and optical amplifier 217 to allow the data to be converted into an optical mode. The data in this form is then distributed to the decoding means locations of the various houses in the estate via the optical cable connection network 219 which is not shown but can be configured by using appropriate splitters to provide the requited data distribution to each of the decoding means locations 224, one of which is represented in Figures 7b and c. It should be appreciated therefore that the description of Figures 7b and c can be repeated at each of the decoding means locations.
In Figure 7b there is shown the provision of the interface 221 which to the user of the apparatus will typically be in the form of a wall plate with a plurality of outlets for connection of cables to allow connection to their apparatus. In this case there will be an outlet port for the satellite data, one for the DTT data and one for the DAB data and to which the user can selectively connect the appropriate equipment.
Prior to these outlets and typically provided as part of the interface there is provided a series of processing components. Firstly the optical data is split and routed via junction box 223 to an access or gateway facility 225 which allows the optical mode of the data to be reconverted into the original received format. From the gateway, the DTT and DAB data can be carried to the interface via cable connections 227 and then onto decoding means 239 in the premises. The satellite antenna data can be split into the high and low frequencies and different polarities as shown in Figure 7c and carried by cables 229 to interface 221 and then onto decoding means 241. In each case the data arrives at the interface in a conventional format.
Figure 7c illustrates how the data once converted from the optical mode can again be destacked and separated into the different formats and/or frequencies and/or polarities using filtering means 237.
It is of course possible that the need for the data to be provided in a conventional format reduces as new generations of decoding means apparatus is introduced. Figure 7b illustrates by broken lines 231 that the optical mode of the data may be maintained rather than being converted and can then be passed to optical modulators 235 and/or receiver 233 as required to allow some or all of the data to be supplied to the interface in an optical mode and used in that form.
Figures 8a-c illustrate a further embodiment of the invention. In this case the system is particularly useful for a building in which there are provided Multiple Dweller Units (MDU's). The apparatus is similar in many components to that of the Figures 7a-c and the same reference numerals are used for the same components of Figures 7a-c. In this case the LNB 243 for the satellite antenna data includes an inbuilt diplexer which receives and stacks the DTT and DAB data via UHF cable 245 from filters 207, 209 and diplexer 247. The LNB can also be provided with optical conversion means to allow the data which is output along cable 219 to be in the optical mode. Figure 8b illustrates the LNB 243 and shows how the same includes the waveguide probes 249 and vertical and horizontal polarisation data paths 251, 253 respectively which lead to the satellite data diplexer 243' and in turn to the diplexer 243" for the DTT and/or DAB data. The combined data is then passed to the laser modulator 215 for conversion into the optical mode to cable connection 219. Figure 8c illustrates how the received data can then be split and processed in a similar manner to that as described with regard to Figure 7b and the same reference numerals and description apply.
Figure 9 illustrates the arrangement at the interface 221 in a further embodiment of the invention. Again the same components as Figures 8c and 7b are referred to by the same reference numerals. In this case the main difference is that the received data from the terrestrial TV antenna is not routed through the system in accordance with the invention and instead the existing UHF distribution cable network 255 is used to transfer the DTT data from the antenna to the decoding means 239. This connection can also be connected to the DAB receiving apparatus and used to distribute the DAB data also. The system incorporating the optical connecting cables is used for the satellite antenna received data only in this format.
The proposed distribution system avoids the current coaxial cable bandwidth limitation and so avoids the need for multiple feeds from the satellite antenna dish and electronic selector switches within the distribution network.
The use of the system as herein described allows the composite signal to be shared between all decoding means and channel selection can then be performed either at each individual decoding means 24, 124, 224 or within equipment located in the customer home distribution network enabling multiple TV's in each home to be served.
Some of the key advantages of fibre networks that make them particularly suited in accordance with the invention are their huge bandwidth, flexible and small cross section cable and extremely low loss. It enables a flexible network to be installed that can be upgraded to support as many locations as the customer needs with minimum difficulty.
The optical fibre cable distribution network of the invention gets round the current coaxial cable bandwidth limitation so avoids the need for multiple feeds from the satellite dish and electronic selector switches within the distribution network.
The use of a passive optical network allows the composite signal to be shared between all decoding means and dwellings and channel selection can then be performed either at each individual TV or within equipment located in the customer home distribution network enabling multiple TV's in each home to be served. The very low attenuation of optical fibre removes any geographical restrictions and allows the receiving location to be located for best reception, for example, one antenna could feed several buildings, and the use of a non-metallic optical fibre cable eliminates the earth bonding problem common with shared infrastructure.
It is also possible to deliver other high bandwidth services around the home over the same network as the satellite TV services.

Claims

A low noise block (LNB) for receiving data which is transmitted thereto via one or more satellite transmission systems and an antenna with respect to which the LNB is located and said data is converted to an optical signal for transfer in an optical format to one or more premises, characterised in that the LNB includes an integrated IF optical converter which includes waveguide probes (249) which split the received data into vertical and horizontal polarization paths which lead to an IF diplexer (213; 243', 243") and in turn a laser modulator (26; 215) to change the format of the data received into a single optical signal output (28) from the LNB.
A LNB according to claim 1 wherein all of the received data is carried in an optical format by the single optical output
A LNB according to claim 1 wherein the data which is received is in a form to allow the data to be decoded to allow television, radio and/or auxiliary services to be provided therefrom.
A LNB according to any of the preceding claims wherein data received via one or more differing transmission systems in the form of any or any combination of a satellite digital broadcast system, a Digital Audio Broadcast (DAB) system and/or Digital terrestrial television (DTT) are combined at the LNB and converted into an optical format and carried as part of the single optical signal output from the LNB.
A LNB according to any of the preceding claims wherein the LNB is connected to a fibre optic cable via a cable termination assembly incorporating a laser, an electronic driver, power feed for the LNB and the optical fibres.
A LNB according to any of the preceding claims wherein the LNB includes a data stacker and said data is separated into Horizontal Low (HL), Horizontal High(HH), Vertical Low(VL) and Vertical High (VH)
A LNB according to any of the preceding claims wherein the LNB includes at least one 4.5MHz-5.45GHz diplexer to configure the data from all sources and which is passed as a combined data signal to the optical converter and laser modulator and optical amplifier to convert the data into an optical mode.
A LNB according to claim 7 wherein the LNB includes a first diplexer for data received by a satellite antenna and a second diplexer for data received via DTT and/or DAB means and the combined data is then passed to a laser modulator for conversion into the optical mode and onwards to the cable connection.