CA2246679A1 - Hybrid fiber-coax telecommunication system - Google Patents
Hybrid fiber-coax telecommunication system Download PDFInfo
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- CA2246679A1 CA2246679A1 CA002246679A CA2246679A CA2246679A1 CA 2246679 A1 CA2246679 A1 CA 2246679A1 CA 002246679 A CA002246679 A CA 002246679A CA 2246679 A CA2246679 A CA 2246679A CA 2246679 A1 CA2246679 A1 CA 2246679A1
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- Prior art keywords
- coax
- signal
- telecommunication system
- hybrid fiber
- mcn
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
- H03D7/16—Multiple-frequency-changing
- H03D7/165—Multiple-frequency-changing at least two frequency changers being located in different paths, e.g. in two paths with carriers in quadrature
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
- Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
Abstract
A Hybrid Fiber-Coax [HFC] telecommunication system including several modulation devices (MCl-MCn) and a combiner device (CSN) coupled thereto. The modulation devices provide modulated telecommunication signals under the form of output currents that are applied to the combiner device that is further connected to a coaxial cable (COAX) for transmitting thereon these modulated signals in predetermined frequency channels according to the Frequency Division Multiple Access [FDMA] structure. The invention consists in operating the combiner device as a current-mode summing node instead as of a voltage-mode summing node. As a result, the implementation is relatively easy, because a current summing node may be just a single junction point, and its linearity is thus obviously high. Furthermore, drivers or power amplifiers are generally not required between the modulation devices and the combiner device because there is no power dissipated in this combiner device, thus no power lossto be compensated. Additionally, the integration volume of the HFC
telecommunication system is reduced, as well as the cost for an external combiner. The invention is also applicable to quadrature-phase modulation systems.
telecommunication system is reduced, as well as the cost for an external combiner. The invention is also applicable to quadrature-phase modulation systems.
Description
HYBRID FIBER-COAX TELECOMMUNICATION SYSTEM
The present invention relates to a Hybrid Fiber-Coax [HFC]
telecommunication system including a plurality of modulation means and a combiner means coupled thereto for receiving therefrom modulated signals, said 5 combiner means being conneded to a coaxial cable for llu~ ;llg thereon said modulated signals in pledelelll~;ned frequency channels, different for each of said modulation means, each of said modulation means including signal mixer means having a first input conneded to c quadrature signal generator adapted to supply a carrier signal thereto, a second input at which an analog 10 telecommunication signal is applied, and an output coupled to said combiner means and at which the modulated signal is provided as a result of a modulation, in said signal mixer means, of said carrier signal by said analog telecommunication signal.
Such a Hybrid Fiber-Coax telecommunication system is generally 15 knawn in the art. The idea of HFC is to put different telecommunication signals, received via optical fibers, onto distind video channels and to apply these channels to the coaxial cable, preferably according to the Frequency Division Multiple Access [FDMA] strudure. Each channel is modulated on a different carrier signal of which the frequency is in the video bond. The outputs of the 20 signal mixer means are generally conneded to distind inputs of the combiner means via drivers. The combiner means sums up the signals at the outputs of the drivers, i.e. sums up the voltages of the modulated signals.
A combiner means comprises at least one combiner as for instance known from Sedion 2: "Power SpliHer/ Combiners" of the "RF/IF Designer's 25 Handbook - Mini-Circuits" edition 92/93 by Scientific Components. In general, a resistive or indudive combiner with an auto-transformer is used per two input signals, i.e. for two modulation means. Several of such combiners are then buildin cascade so as to constitute a combiner means adapted to accept up to 12 voltage mode input signals on a 50 or 75 Ohm interface. For each of these 30 combiners, an auto-l,uu~rullller introduces a 3 dB attenuation per two signals summed up, whilst a resistive combiner introduces a 6 dB aHenuation.
This loss is a problem for the power of the cbove drivers. In fad, the driver is a power amplifier of which all the power is dissipated in the combinerconnected thereto.
Another problem of the known HFC telecommunication system is the 5 linearity requirement that is generally critical at the high frequencies wherein the system is used.
An objed of the present invention is to provide a Hybrid Fiber-Coax telecommunication system of the known type but wherein the power consumption is reduced cnd the linearity is optimized.
According to the invention, this obied is achieved due to the fad that said signal mixer means of each modulotion means are adcpted to provide, cs modulated signal, an output current, and that said combiner mecns is a current summing node for the output currents of the signal mixer mecns of soid plurclityof modulation means.
The invention thus consists in operating the combiner means as a current-mode summing node instead of as a voltage-mode summing node. The i",ple",e" 1 of a current summing node is relatively easy and its linearity is higher than that of o voltoge summing node. Furthermore, drivers or power amplifiers are no longer required because there is no power dissipated in such acombiner means, thus no power loss to be cu,,,pansul~d. Additionolly, the integration volume of the HFC telecommunicotion system is reduced, os well as the cast far cn external combiner.
Another uhu~u~lefi~lic feoture of the present invention is that said current summing node is a jundion point coupled to the outputs of said signal mixer means cnd to said coaxicl cable.
Summing of currents just needs to short the outputs of the current sources, i.e., in the present ap,'l- ~n, the signol mixer means. By reducing thecombiner means to a single jundion point, the linearity of the system is obviously optimized.
Also onother .1 ,u, u~ 8~1;c feature of the present invention is thot each of said signal mixer means includes a pair of mixer circuits to which quadrature carrier signols and quadrature analog telecommunication signals are applied via said first and second input ,~,pe.~ !y.
The present invention is thereby applicable to telecommunication systems of the quadrature-phase modulation type.
In a variant of the present invention, the outputs of the mixer circuits of each of said modulation means are coupled to the first mentioned current summing node via the cascade .on,)e~lion of a second current summing node and a current amplifier.
In some ,, ' ~s, current amplifiers may be necessary, for instance if the output currents of the mixer circuits are insufficient to be directly applied to the coaxial cable.
As the telecommunication signol provided to the modulation means is generally a digital signal, the present invention is also ~hulu~lel;~td in thot said modulation means further includes digital-to-analog converter means connected to said second input of said signal mixer means and adapted to receive the telecommunication signal in a digital form and to convert it into an analog formprior to apply it to said signal mixer means.
Further .1 ,u, u~le l ;,i;c features of the present Hybrid Fiber-Coax telecommunication system are mentioned in the appended claims.
The abave and other objects and features of the invention will become more apparent and the inventian itself will be best understood by referring to the following description of an e",bod;",e"l taken in conjunction with the a.co",pu"l;ng drawings wherein:
Fig. 1 shows a Hybrid Fiber-Coax [HFC] telecommunication system including several modulation devices (h\Cl-MCn) and a cambiner device (CSN) according to the invention; and Fig. 2 shows a variant of the telecommunication system of Fig. 1.
The Hybrid Fiber-Coax [HFC] telecommunication system shown in Fig. 1 is used to transmit telecommunication signals, received via different optical fibers, towards a single coaxial cable COAX onto which these signals are llun~nl;lldcl according to the known Frequency Division h~ultiple Access [FDMA]
structure. To this end, the telecommunication system includes n, soy n= 12, modulation devices MCl-MCn odopted to receive the telecommunication signals in a digital form at cn input 11-ln thereof, and a current summing node CSN
summing-up the output currents of the modulation devices and opplying the result of this sum to the coaxial cable COAX.
S Each of the modulation devices MCl/MCn includes two digital-to-analog converters DAIl/DAln and DAQl/DAQn having their input connected in common to the input ll/ln of the modulation device and being able to convert the digital telecommunication signal received at this input into on onolog telecommunication signal. The outputs of the digitol-to-analog converters are signals I and Q in quadrature of phase. This means that the analog telecommunication signals at the outputs of the two converters hove a relative phase difference of 90~. Each converter DAIl/DAln, DAQl/DAQn is connected to o first input of a distinct mixer circuit MXIl/MXln, MXQl/MXQn. A second input of these mixer circuits is connected to o quodrature signal generator QGl/QGn that provides a carrier signal of which the frequency is in or above the video-band, that ranges from 50 MHz to 800 MHz.
In more detail, the two mixer circuits MXIl/MXln and MXQl/MXQn of a modulation device MCl/MCn form together o mixer device MXl/MXn to which the digital-to-analog converters DAIl/DAln and DAQl/DAQn as well as the quadrature signal generator QGl/QGn are connected. An "in-phase" carrier signal 0~ is provided by the quadrature signal generator and is applied to a first mixer circuit MXIl/MXln of the mixer device MXl/MXn, whilst an Nin-quadrature"
(of phase) carrier signal 90~, also provided by the quodrature signal generator, is applied to the second mixer circuit MXQl/MXQn of the mixer device. The mixer circuits are adapted to modulote the incoming carrier signal with the incoming analog telecommunication signal and to provide an output current as resulting modulated signal. The output currents of the two mixer circuits MXIl/MXln ond MXQl/MXQn are applied to inputs of a current summing node CSl/CSn forming part of the modulation device MCl/MCn. The output of this current summing node CSl/CSn is connected to an input of a current amplifier CAl/CAn that also forms part of the modulation device MCl/MCn.
It is to be noted that the current summing node CSl/CSn is in fad only a junction point between the outputs of the mixer circuits and the current amplifier.
The structure of the present HFC le:le~ullllnunication system is such 5 that each modulation device MCl/MCn and more particularly the quadrature signal generator QGl/QGn thereof operotes at a different frequency and at a different time moment so that, at outputs Ol/On of the modulation devices MCl/MCn, the like-named telecommunication signals ore moduloted on different video frequency channels. As already ",e"l;oned, these modulated 10 signals Ol/On are provided under the form of currents. The frequency channels are then applied to another current summing node CSN where there are summed-up and the result of this sum is applied to the cooxiol cable COAX. Here again, to sum-up the output currents from the different modulations devices MCl-MCn, the current summing node CSN may only consist in a junction point 15 of the co~ p~",d",g outputs Ol-On with the coaxial cable COAX.
When the currents at the outputs of the modulation devices MCl-MCn, and more particularly at the outputs of the mixer circuits MXIl, MXln and MXQl, MXQn thereof, is sufficiently high, the HFC telecommunication system may be simplified into a variant as shown in Fig. 2. Therein, the above current 20 summing nodes CSl-CSn and the current amplifiers CAl-CAn are removed from the modulation devices MCl'-MCn'. As a result, the modulated signals or currents Oll, Oln/ OQl, OQn ot the like-nomed outputs of the first MXIl/MXln and the second hlXQl/MXQn mixer circuit of the mixer devices MXl/MXn respedively~ are directly applied to the current summing node, i.e. to the junction 25 point CSN. In this variant of e"~bod""e"l, the number of used ~ pone~, is obviously reduced.
Whjle the principles of the invention have been described above in connection with specific apparatus, e.g. quadrature phase modulation, it is to be clearly understood that this des.,i~.lion is made only by way of example and not30 as a limitation on the scope of the invention thot is defined in the oppended claims.
.,
The present invention relates to a Hybrid Fiber-Coax [HFC]
telecommunication system including a plurality of modulation means and a combiner means coupled thereto for receiving therefrom modulated signals, said 5 combiner means being conneded to a coaxial cable for llu~ ;llg thereon said modulated signals in pledelelll~;ned frequency channels, different for each of said modulation means, each of said modulation means including signal mixer means having a first input conneded to c quadrature signal generator adapted to supply a carrier signal thereto, a second input at which an analog 10 telecommunication signal is applied, and an output coupled to said combiner means and at which the modulated signal is provided as a result of a modulation, in said signal mixer means, of said carrier signal by said analog telecommunication signal.
Such a Hybrid Fiber-Coax telecommunication system is generally 15 knawn in the art. The idea of HFC is to put different telecommunication signals, received via optical fibers, onto distind video channels and to apply these channels to the coaxial cable, preferably according to the Frequency Division Multiple Access [FDMA] strudure. Each channel is modulated on a different carrier signal of which the frequency is in the video bond. The outputs of the 20 signal mixer means are generally conneded to distind inputs of the combiner means via drivers. The combiner means sums up the signals at the outputs of the drivers, i.e. sums up the voltages of the modulated signals.
A combiner means comprises at least one combiner as for instance known from Sedion 2: "Power SpliHer/ Combiners" of the "RF/IF Designer's 25 Handbook - Mini-Circuits" edition 92/93 by Scientific Components. In general, a resistive or indudive combiner with an auto-transformer is used per two input signals, i.e. for two modulation means. Several of such combiners are then buildin cascade so as to constitute a combiner means adapted to accept up to 12 voltage mode input signals on a 50 or 75 Ohm interface. For each of these 30 combiners, an auto-l,uu~rullller introduces a 3 dB attenuation per two signals summed up, whilst a resistive combiner introduces a 6 dB aHenuation.
This loss is a problem for the power of the cbove drivers. In fad, the driver is a power amplifier of which all the power is dissipated in the combinerconnected thereto.
Another problem of the known HFC telecommunication system is the 5 linearity requirement that is generally critical at the high frequencies wherein the system is used.
An objed of the present invention is to provide a Hybrid Fiber-Coax telecommunication system of the known type but wherein the power consumption is reduced cnd the linearity is optimized.
According to the invention, this obied is achieved due to the fad that said signal mixer means of each modulotion means are adcpted to provide, cs modulated signal, an output current, and that said combiner mecns is a current summing node for the output currents of the signal mixer mecns of soid plurclityof modulation means.
The invention thus consists in operating the combiner means as a current-mode summing node instead of as a voltage-mode summing node. The i",ple",e" 1 of a current summing node is relatively easy and its linearity is higher than that of o voltoge summing node. Furthermore, drivers or power amplifiers are no longer required because there is no power dissipated in such acombiner means, thus no power loss to be cu,,,pansul~d. Additionolly, the integration volume of the HFC telecommunicotion system is reduced, os well as the cast far cn external combiner.
Another uhu~u~lefi~lic feoture of the present invention is that said current summing node is a jundion point coupled to the outputs of said signal mixer means cnd to said coaxicl cable.
Summing of currents just needs to short the outputs of the current sources, i.e., in the present ap,'l- ~n, the signol mixer means. By reducing thecombiner means to a single jundion point, the linearity of the system is obviously optimized.
Also onother .1 ,u, u~ 8~1;c feature of the present invention is thot each of said signal mixer means includes a pair of mixer circuits to which quadrature carrier signols and quadrature analog telecommunication signals are applied via said first and second input ,~,pe.~ !y.
The present invention is thereby applicable to telecommunication systems of the quadrature-phase modulation type.
In a variant of the present invention, the outputs of the mixer circuits of each of said modulation means are coupled to the first mentioned current summing node via the cascade .on,)e~lion of a second current summing node and a current amplifier.
In some ,, ' ~s, current amplifiers may be necessary, for instance if the output currents of the mixer circuits are insufficient to be directly applied to the coaxial cable.
As the telecommunication signol provided to the modulation means is generally a digital signal, the present invention is also ~hulu~lel;~td in thot said modulation means further includes digital-to-analog converter means connected to said second input of said signal mixer means and adapted to receive the telecommunication signal in a digital form and to convert it into an analog formprior to apply it to said signal mixer means.
Further .1 ,u, u~le l ;,i;c features of the present Hybrid Fiber-Coax telecommunication system are mentioned in the appended claims.
The abave and other objects and features of the invention will become more apparent and the inventian itself will be best understood by referring to the following description of an e",bod;",e"l taken in conjunction with the a.co",pu"l;ng drawings wherein:
Fig. 1 shows a Hybrid Fiber-Coax [HFC] telecommunication system including several modulation devices (h\Cl-MCn) and a cambiner device (CSN) according to the invention; and Fig. 2 shows a variant of the telecommunication system of Fig. 1.
The Hybrid Fiber-Coax [HFC] telecommunication system shown in Fig. 1 is used to transmit telecommunication signals, received via different optical fibers, towards a single coaxial cable COAX onto which these signals are llun~nl;lldcl according to the known Frequency Division h~ultiple Access [FDMA]
structure. To this end, the telecommunication system includes n, soy n= 12, modulation devices MCl-MCn odopted to receive the telecommunication signals in a digital form at cn input 11-ln thereof, and a current summing node CSN
summing-up the output currents of the modulation devices and opplying the result of this sum to the coaxial cable COAX.
S Each of the modulation devices MCl/MCn includes two digital-to-analog converters DAIl/DAln and DAQl/DAQn having their input connected in common to the input ll/ln of the modulation device and being able to convert the digital telecommunication signal received at this input into on onolog telecommunication signal. The outputs of the digitol-to-analog converters are signals I and Q in quadrature of phase. This means that the analog telecommunication signals at the outputs of the two converters hove a relative phase difference of 90~. Each converter DAIl/DAln, DAQl/DAQn is connected to o first input of a distinct mixer circuit MXIl/MXln, MXQl/MXQn. A second input of these mixer circuits is connected to o quodrature signal generator QGl/QGn that provides a carrier signal of which the frequency is in or above the video-band, that ranges from 50 MHz to 800 MHz.
In more detail, the two mixer circuits MXIl/MXln and MXQl/MXQn of a modulation device MCl/MCn form together o mixer device MXl/MXn to which the digital-to-analog converters DAIl/DAln and DAQl/DAQn as well as the quadrature signal generator QGl/QGn are connected. An "in-phase" carrier signal 0~ is provided by the quadrature signal generator and is applied to a first mixer circuit MXIl/MXln of the mixer device MXl/MXn, whilst an Nin-quadrature"
(of phase) carrier signal 90~, also provided by the quodrature signal generator, is applied to the second mixer circuit MXQl/MXQn of the mixer device. The mixer circuits are adapted to modulote the incoming carrier signal with the incoming analog telecommunication signal and to provide an output current as resulting modulated signal. The output currents of the two mixer circuits MXIl/MXln ond MXQl/MXQn are applied to inputs of a current summing node CSl/CSn forming part of the modulation device MCl/MCn. The output of this current summing node CSl/CSn is connected to an input of a current amplifier CAl/CAn that also forms part of the modulation device MCl/MCn.
It is to be noted that the current summing node CSl/CSn is in fad only a junction point between the outputs of the mixer circuits and the current amplifier.
The structure of the present HFC le:le~ullllnunication system is such 5 that each modulation device MCl/MCn and more particularly the quadrature signal generator QGl/QGn thereof operotes at a different frequency and at a different time moment so that, at outputs Ol/On of the modulation devices MCl/MCn, the like-named telecommunication signals ore moduloted on different video frequency channels. As already ",e"l;oned, these modulated 10 signals Ol/On are provided under the form of currents. The frequency channels are then applied to another current summing node CSN where there are summed-up and the result of this sum is applied to the cooxiol cable COAX. Here again, to sum-up the output currents from the different modulations devices MCl-MCn, the current summing node CSN may only consist in a junction point 15 of the co~ p~",d",g outputs Ol-On with the coaxial cable COAX.
When the currents at the outputs of the modulation devices MCl-MCn, and more particularly at the outputs of the mixer circuits MXIl, MXln and MXQl, MXQn thereof, is sufficiently high, the HFC telecommunication system may be simplified into a variant as shown in Fig. 2. Therein, the above current 20 summing nodes CSl-CSn and the current amplifiers CAl-CAn are removed from the modulation devices MCl'-MCn'. As a result, the modulated signals or currents Oll, Oln/ OQl, OQn ot the like-nomed outputs of the first MXIl/MXln and the second hlXQl/MXQn mixer circuit of the mixer devices MXl/MXn respedively~ are directly applied to the current summing node, i.e. to the junction 25 point CSN. In this variant of e"~bod""e"l, the number of used ~ pone~, is obviously reduced.
Whjle the principles of the invention have been described above in connection with specific apparatus, e.g. quadrature phase modulation, it is to be clearly understood that this des.,i~.lion is made only by way of example and not30 as a limitation on the scope of the invention thot is defined in the oppended claims.
.,
Claims (11)
1. Hybrid Fiber-Coax [HFC] telecommunication system including a plurality of modulation means (MC1-MCn) and a combiner means (CSN) coupled thereto for receiving therefrom modulated signals (O1-On), said combiner means being connected to a coaxial cable (COAX) for transmitting thereon said modulated signals in predetermined frequency channels, different for each of said modulation means, each of said modulation means (MC1/MCn) including signal mixer means (MX1/MXn) having a first input connected to a quadrature signal generator (QG1/QGn) adapted to supply a carrier signal (0°, 90°) thereto, a second input at which an analog telecommunication signal (~, Q) is applied, and an output coupled to said combiner means and at which the modulated signal is provided as a result of a modulation, in said signal mixer means, of said carrier signal by said analog telecommunication signal, characterized in that said signal mixer means (MX1/MXn) of each modulation means (MC1/MCn) are adapted to provide, as modulated signal (O1/On), an output current, and in that said combiner means (CSN) is a current summing node for the output currents of the signal mixer means of said pluralityof modulation means.
2. Hybrid Fiber-Coax telecommunication system according to claim 1, characterized in that said current summing node (CSN) is a junction point coupled to the outputs of said signal mixer means (MX1/MXn) and to said coaxial cable (COAX).
3. Hybrid Fiber-Coax telecommunication system according to claim 1, characterized in that each of said signal mixer means (MX1/MXn) includes a pair of mixer circuits (MX~~, MXQ1/MX~n, MXQn) to which quadrature carrier signals (0°, 90°) and quadrature analog telecommunication signals (~, Q) are applied via said first and second input respectively.
4. Hybrid Fiber-Coax telecommunication system according to claim 3, characterized in that the outputs of the mixer circuits (MX~~, MXQ1/MX1n, MXQn) of each of said modulation means (MC1/MCn) are coupled to the first mentioned current summing node (CSN) via the cascade connection of a second current summing node (CS1/CSn) and a current amplifier (CA1/CAn).
5. Hybrid Fiber-Coax telecommunication system according to claim 4, characterized in that, for each of said modulation means (MC1/MCn), said second current summing node (CS1/CSn) is a junction point between the outputs of said mixer circuits (MX~~, MXQ1/MX1n, MXQn) and an input of said current amplifier (CA1/CAn).
6. Hybrid Fiber-Coax telecommunication system according to claim 4, characterized in that said second current summing node (CS1/CSn) and said current amplifier (CA1/CAn) are included in said modulation means (MC1/MCn).
7. Hybrid Fiber-Coax telecommunication system according to claim 1, characterized in that said modulation means (MC1/MCn) further includes digital-to-analog converter means (DA~~, DAQ1/DA1n, DAQn) connected to said second input of said signal mixer means (MX1/MXn) and adapted to receive the telecommunication signal in a digital form and to convert it into an analog form(~, Q) prior to apply it to said signal mixer means.
8. Hybrid Fiber-Coax telecommunication system according to the claims 3 and 7, characterized in that said digital-to-analog converter means (DA~~, DAQ1/DA1n, DAQn) includes a pair of digital-to-analog converters adapted to provide said quadrature analog telecommunication signal (1, Q).
9. Hybrid Fiber-Coax telecommunication system according to claim 1, characterized in that the frequency of the carrier signal (0°, 90°) supplied by said quadrature signal generator (QG1/QGn) is different for each modulation means (MC1/MCn) of said plurality.
10. Hybrid Fiber-Coax telecommunication system according to claim 1, characterized in that said plurality is constituted by 12 (n) modulation means (MC1-MCn) coupled to said combiner means (CSN).
11. Hybrid Fiber-Coax telecommunication system according to claim 1, characterized in that said system operates according to the Frequency Division Multiple Access [FDMA] structure.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP97402382A EP0909020B1 (en) | 1997-10-10 | 1997-10-10 | Hybrid fiber-coax telecommunication system |
| EP97402382.2 | 1997-10-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2246679A1 true CA2246679A1 (en) | 1999-04-10 |
Family
ID=8229875
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002246679A Abandoned CA2246679A1 (en) | 1997-10-10 | 1998-10-07 | Hybrid fiber-coax telecommunication system |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US6357044B1 (en) |
| EP (1) | EP0909020B1 (en) |
| CA (1) | CA2246679A1 (en) |
| DE (1) | DE69735085T2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6816512B2 (en) * | 1999-12-30 | 2004-11-09 | General Instrument Corporation | Arrangement for managing multiple telephone lines terminating at a single location |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2510299B2 (en) * | 1989-03-22 | 1996-06-26 | オリンパス光学工業株式会社 | Electronic endoscope system |
| US5351016A (en) * | 1993-05-28 | 1994-09-27 | Ericsson Ge Mobile Communications Inc. | Adaptively self-correcting modulation system and method |
| US5581555A (en) * | 1993-09-17 | 1996-12-03 | Scientific-Atlanta, Inc. | Reverse path allocation and contention resolution scheme for a broadband communications system |
| US5471497A (en) * | 1993-11-01 | 1995-11-28 | Zehavi; Ephraim | Method and apparatus for variable rate signal transmission in a spread spectrum communication system using coset coding |
| US5745837A (en) * | 1995-08-25 | 1998-04-28 | Terayon Corporation | Apparatus and method for digital data transmission over a CATV system using an ATM transport protocol and SCDMA |
| US5805583A (en) * | 1995-08-25 | 1998-09-08 | Terayon Communication Systems | Process for communicating multiple channels of digital data in distributed systems using synchronous code division multiple access |
| EP0762766A3 (en) * | 1995-09-12 | 1997-11-05 | AT&T Corp. | Network apparatus and method for providing two-way broadband communications |
| EP1062444A4 (en) * | 1996-10-22 | 2001-04-11 | Kalsi Eng Inc | Improved flexible wedge gate valve |
| US5838268A (en) * | 1997-03-14 | 1998-11-17 | Orckit Communications Ltd. | Apparatus and methods for modulation and demodulation of data |
-
1997
- 1997-10-10 DE DE69735085T patent/DE69735085T2/en not_active Expired - Fee Related
- 1997-10-10 EP EP97402382A patent/EP0909020B1/en not_active Expired - Lifetime
-
1998
- 1998-10-02 US US09/165,948 patent/US6357044B1/en not_active Expired - Fee Related
- 1998-10-07 CA CA002246679A patent/CA2246679A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| DE69735085D1 (en) | 2006-04-06 |
| EP0909020A1 (en) | 1999-04-14 |
| DE69735085T2 (en) | 2006-08-31 |
| US6357044B1 (en) | 2002-03-12 |
| EP0909020B1 (en) | 2006-01-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |