Unicable
Encyclopedia
Single Cable Distribution is a satellite TV technology that enables the delivery of broadcast programming to multiple users over a single coaxial cable, and eliminates the numerous cables required to support consumer electronics devices such as twin-tuner Digital Video Recorders (DVRs) and high end receivers.
Without single cable distribution, providing full spectrum access for multiple receivers, or receivers with multiple tuners, in a single family home has required a separate coaxial cable feeding each tuner from the antenna equipment (either multiple LNB
s, a multi-output LNB or a multiswitch distribution system) because of the large bandwidth requirement of the signals.
Single cable distribution technology enables one coaxial cable from the antenna equipment to multiple tuners, to provide independent tuning across the whole range of satellite reception for each tuner.
A European industry standard for distributing satellite signals over a single coaxial cable - CENELEC EN50494 - has been developed by a consortium led by SES Astra
.
Single cable distribution technology can be found in commercial equipment with the Unicable trademark from FTA Communications Technologies. Unicable uses an integrated software and hardware solution that allows Unicable-certified Digital Video Recorders and receivers to multiplex selected programming when using Unicable LNB or multiswitching products.
The Unicable Interoperability Platform is open to companies designing and/or marketing satellite and other broadcast-related products. The platform is designed to facilitate the acceptance of Unicable-certified solutions in the consumer TV broadcast market.
. The receiver requests a particular transponder frequency via a DiSEqC
-compliant command. A mixer
in the dish-end equipment (an LNB or distribution unit) converts the received signal to the correct user band IF
centre frequency for that receiver.
The converted transponders of the various users are then combined, and sent via the single coaxial cable to the receivers. The combined signal is tapped or split to reach every user.
(low frequency/horizontal polarity, high frequency/horizontal polarity, low frequency/vertical polarity, high frequency/vertical polarity) are received by a conventional front end, amplified and downconverted to the L-band, to be fed to a number of Single Cable Router (SCR) chips – one for each user that can be connected - to further downconvert the required section of the received spectrum to centre on the user band IF frequency.
The LNB further includes a mixer to combine the user bands together and a microcontroller to receive the instructions as to which frequency is required by each user and control the SCR chips.
Alternatively, a single cable distribution system can use a conventional LNB feeding the four sub-bands to a separate SCR device, as a substitute for a traditional multiswitch, that needs a dedicated coaxial cable for every receiver (or tuner) connected.
Unicable LNBs and SCRs also include either a legacy mode of operation or a legacy output which provides conventional LNB IF for use with an installation of non-Unicable receivers.
A receiver required to operate in a single cable distribution installation can be essentially conventional. It should be able to tune to the user channel (within the normal IF tuning range) and modulate the LNB power voltage with the 22 kHz signal required for issuing DiSEqC commands. It will then require only software modification to operate as a single cable distribution receiver.
For correct operation, two-way splitters are required to feed the combined signal to each receiver. These allow bi-directional passage of both RF and DC signals, to provide for the passing of DiSEqC commands between the LNB and receiver(s).
As of March 2010, SES Astra's Single Cable Distribution factsheet lists 88 receivers as supporting single cable distribution technology although this list is not exhaustive. Several receivers for the HD+
German high definition platform broadcast from Astra 19.2°E
are compatible with the SCR system.
s (IRS) often provide only one satellite feed to each household, preventing the use of dual-tuner DVRs. Upgrading the multiswitch
es and cabling to provide two or more feeds per household is usually both costly and invasive. However, individual households or sections of the system can be converted to SCR distribution so that multiple tuners within a household can be fed via the single existing coaxial cable.
Equipment such as Inverto’s Unicable Cascadable Switch can be connected to a conventional quattro LNB to provide a single SCR output and a conventional LNB output. The four IF inputs from the Quattro LNB are looped through to outputs so the unit can be cascaded to further SCR switches or to the existing multiswitches of the IRS, so an SCR-enabled output is provided without replacing the existing LNB or affecting the provision for conventional receivers in other households served by the rest of the system.
Versions of the Unicable Switch to provide for four and eight tuners within a household are available, and to combine a digital terrestrial signal onto the SCR-enabled output as well.
Global Invacom’s SCR Adaptor unit performs a similar function but is connected to the existing multiswitch outputs, to provide SCR compatibility for one connection (one household) of an existing IRS.
The SCR Adaptor connects to four outputs of an IRS multiswitch and provides a single SCR output that is typically connected to the existing single coaxial cable to the household to be converted. A further four conventional IF outputs are provided to recover usage of the existing multiswitch outputs for other households. Within the SCR enabled household, a splitter and power injector provides power to the SCR Adaptor and splits the signal to feed the separate tuners connected.
Global Invacom developed the SCR Adaptor in conjunction with BSkyB to enable flats and homes with single-feed distribution systems to fit Sky+
and Sky+ HD dual-tuner DVR receivers.
using optical fibre. The high bandwidth of optical connections allows for the full satellite spectrum received at the dish to be accommodated on one fibre optic cable, which can be easily optically split to provide that full spectrum signal to a large number of receivers.
UK company, Global Invacom (which also developed and markets SCR single cable distribution equipment) has developed a low cost system of fibre optic distribution suitable for domestic installations and small or medium commercial communal dish systems, with an optical output LNB, fibre cables, splitters, and converter units to return the optical signal to an electrical one compatible with legacy receivers.
The extremely low signal loss through fibre optic cables and complete elimination of interference and noise picked up by the cable mean that such a system can support very long cable runs between the dish and the converters in a widespread communal dish system, and a smaller dish can be used as the communal antenna.
Global Invacom won the Astra Innovation Contest run by satellite operator SES Astra
in 2007 for the proposal and initial development of optical fibre distribution systems for satellite TV.
Without single cable distribution, providing full spectrum access for multiple receivers, or receivers with multiple tuners, in a single family home has required a separate coaxial cable feeding each tuner from the antenna equipment (either multiple LNB
Low-noise block converter
A low-noise block downconverter is the receiving device of a parabolic satellite dish antenna of the type commonly used for satellite TV reception...
s, a multi-output LNB or a multiswitch distribution system) because of the large bandwidth requirement of the signals.
Single cable distribution technology enables one coaxial cable from the antenna equipment to multiple tuners, to provide independent tuning across the whole range of satellite reception for each tuner.
A European industry standard for distributing satellite signals over a single coaxial cable - CENELEC EN50494 - has been developed by a consortium led by SES Astra
SES Astra
Astra is the name for the geostationary communication satellites, both individually and as a group, which are owned and operated by SES S.A., a global satellite operator based in Betzdorf, in eastern Luxembourg. The name is sometimes also used to describe the channels broadcasting from these...
.
Single cable distribution technology can be found in commercial equipment with the Unicable trademark from FTA Communications Technologies. Unicable uses an integrated software and hardware solution that allows Unicable-certified Digital Video Recorders and receivers to multiplex selected programming when using Unicable LNB or multiswitching products.
The Unicable Interoperability Platform is open to companies designing and/or marketing satellite and other broadcast-related products. The platform is designed to facilitate the acceptance of Unicable-certified solutions in the consumer TV broadcast market.
How it works
Each satellite receiver in the installation has a dedicated user band of a bandwidth approximately the same as a transponderTransponder
In telecommunication, the term transponder has the following meanings:...
. The receiver requests a particular transponder frequency via a DiSEqC
DiSEqC
DiSEqC , pronounced "Die-Sec", is a special communication protocol for use between a satellite receiver and a device such as a multi-dish switch or a small dish antenna rotor...
-compliant command. A mixer
Electronic mixer
An electronic mixer is a device that combines two or more electrical or electronic signals into one or two composite output signals. There are two basic circuits that both use the term mixer, but they are very different types of circuits: additive mixers and multiplying mixers...
in the dish-end equipment (an LNB or distribution unit) converts the received signal to the correct user band IF
Intermediate frequency
In communications and electronic engineering, an intermediate frequency is a frequency to which a carrier frequency is shifted as an intermediate step in transmission or reception. The intermediate frequency is created by mixing the carrier signal with a local oscillator signal in a process called...
centre frequency for that receiver.
The converted transponders of the various users are then combined, and sent via the single coaxial cable to the receivers. The combined signal is tapped or split to reach every user.
Equipment
Special LNBs have been developed for use in single cable distribution systems. All four sub-bands of the Ku bandKu band
The Kμ band is a portion of the electromagnetic spectrum in the microwave range of frequencies. This symbol refers to —in other words, the band directly below the K-band...
(low frequency/horizontal polarity, high frequency/horizontal polarity, low frequency/vertical polarity, high frequency/vertical polarity) are received by a conventional front end, amplified and downconverted to the L-band, to be fed to a number of Single Cable Router (SCR) chips – one for each user that can be connected - to further downconvert the required section of the received spectrum to centre on the user band IF frequency.
The LNB further includes a mixer to combine the user bands together and a microcontroller to receive the instructions as to which frequency is required by each user and control the SCR chips.
Alternatively, a single cable distribution system can use a conventional LNB feeding the four sub-bands to a separate SCR device, as a substitute for a traditional multiswitch, that needs a dedicated coaxial cable for every receiver (or tuner) connected.
Unicable LNBs and SCRs also include either a legacy mode of operation or a legacy output which provides conventional LNB IF for use with an installation of non-Unicable receivers.
A receiver required to operate in a single cable distribution installation can be essentially conventional. It should be able to tune to the user channel (within the normal IF tuning range) and modulate the LNB power voltage with the 22 kHz signal required for issuing DiSEqC commands. It will then require only software modification to operate as a single cable distribution receiver.
For correct operation, two-way splitters are required to feed the combined signal to each receiver. These allow bi-directional passage of both RF and DC signals, to provide for the passing of DiSEqC commands between the LNB and receiver(s).
As of March 2010, SES Astra's Single Cable Distribution factsheet lists 88 receivers as supporting single cable distribution technology although this list is not exhaustive. Several receivers for the HD+
HD+
This article is about the television service "HD+"; for the computer screen resolution see Computer display standard.HD+ is a package of high definition digital satellite TV channels for German-speaking viewers and the company providing that package, based in Unterföhring near Munich, Germany...
German high definition platform broadcast from Astra 19.2°E
Astra 19.2°E
Astra 19.2°E is the name for the group of communications satellites co-located at the 19.2°East orbital position in the Clarke Belt that are owned and operated by SES Astra, a subsidiary of SES based in Betzdorf, Luxembourg....
are compatible with the SCR system.
Use in Legacy Communal TV Systems
Existing communal integrated reception systemIntegrated reception system
An integrated reception system provides broadcast signals from multiple sources to multiple outlets, via a single aerial cluster and signal booster-distributor...
s (IRS) often provide only one satellite feed to each household, preventing the use of dual-tuner DVRs. Upgrading the multiswitch
Multiswitch
A multiswitch is a device used with a quattro LNB to distribute satellite TV signals to multiple receivers from a single dish and LNB....
es and cabling to provide two or more feeds per household is usually both costly and invasive. However, individual households or sections of the system can be converted to SCR distribution so that multiple tuners within a household can be fed via the single existing coaxial cable.
Equipment such as Inverto’s Unicable Cascadable Switch can be connected to a conventional quattro LNB to provide a single SCR output and a conventional LNB output. The four IF inputs from the Quattro LNB are looped through to outputs so the unit can be cascaded to further SCR switches or to the existing multiswitches of the IRS, so an SCR-enabled output is provided without replacing the existing LNB or affecting the provision for conventional receivers in other households served by the rest of the system.
Versions of the Unicable Switch to provide for four and eight tuners within a household are available, and to combine a digital terrestrial signal onto the SCR-enabled output as well.
Global Invacom’s SCR Adaptor unit performs a similar function but is connected to the existing multiswitch outputs, to provide SCR compatibility for one connection (one household) of an existing IRS.
The SCR Adaptor connects to four outputs of an IRS multiswitch and provides a single SCR output that is typically connected to the existing single coaxial cable to the household to be converted. A further four conventional IF outputs are provided to recover usage of the existing multiswitch outputs for other households. Within the SCR enabled household, a splitter and power injector provides power to the SCR Adaptor and splits the signal to feed the separate tuners connected.
Global Invacom developed the SCR Adaptor in conjunction with BSkyB to enable flats and homes with single-feed distribution systems to fit Sky+
Sky+
Sky+, or Sky Plus, is a personal video recorder service for Sky in the UK. Launched in September 2001, it allows the user to record, pause and instantly rewind live TV. The system performs these functions using an internal hard drive inside the Sky+ set top box...
and Sky+ HD dual-tuner DVR receivers.
Fibre Optic Alternative
An alternative approach to that provided by single cable distribution of the signal from a single LNB to multiple receivers, or receivers with multiple tuners, is offered by the use of fibre satellite distributionFibre satellite distribution
Fibre satellite distribution is a technology that enables satellite TV signals from an antenna to be distributed using an optical fibre cable infrastructure and then converted to electrical signals for use with conventional set-top box receivers....
using optical fibre. The high bandwidth of optical connections allows for the full satellite spectrum received at the dish to be accommodated on one fibre optic cable, which can be easily optically split to provide that full spectrum signal to a large number of receivers.
UK company, Global Invacom (which also developed and markets SCR single cable distribution equipment) has developed a low cost system of fibre optic distribution suitable for domestic installations and small or medium commercial communal dish systems, with an optical output LNB, fibre cables, splitters, and converter units to return the optical signal to an electrical one compatible with legacy receivers.
The extremely low signal loss through fibre optic cables and complete elimination of interference and noise picked up by the cable mean that such a system can support very long cable runs between the dish and the converters in a widespread communal dish system, and a smaller dish can be used as the communal antenna.
Global Invacom won the Astra Innovation Contest run by satellite operator SES Astra
SES Astra
Astra is the name for the geostationary communication satellites, both individually and as a group, which are owned and operated by SES S.A., a global satellite operator based in Betzdorf, in eastern Luxembourg. The name is sometimes also used to describe the channels broadcasting from these...
in 2007 for the proposal and initial development of optical fibre distribution systems for satellite TV.
See also
- Fibre satellite distributionFibre satellite distributionFibre satellite distribution is a technology that enables satellite TV signals from an antenna to be distributed using an optical fibre cable infrastructure and then converted to electrical signals for use with conventional set-top box receivers....
- SES AstraSES AstraAstra is the name for the geostationary communication satellites, both individually and as a group, which are owned and operated by SES S.A., a global satellite operator based in Betzdorf, in eastern Luxembourg. The name is sometimes also used to describe the channels broadcasting from these...
- Satellite televisionSatellite televisionSatellite television is television programming delivered by the means of communications satellite and received by an outdoor antenna, usually a parabolic mirror generally referred to as a satellite dish, and as far as household usage is concerned, a satellite receiver either in the form of an...
- Satellite dishSatellite dishA satellite dish is a dish-shaped type of parabolic antenna designed to receive microwaves from communications satellites, which transmit data transmissions or broadcasts, such as satellite television.-Principle of operation:...
- Microwave antenna