WO2000048314A1 - Multiplexage et demultiplexage de services bande etroite et bande large dans une connexion de transmission - Google Patents

Multiplexage et demultiplexage de services bande etroite et bande large dans une connexion de transmission Download PDF

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Publication number
WO2000048314A1
WO2000048314A1 PCT/FI2000/000112 FI0000112W WO0048314A1 WO 2000048314 A1 WO2000048314 A1 WO 2000048314A1 FI 0000112 W FI0000112 W FI 0000112W WO 0048314 A1 WO0048314 A1 WO 0048314A1
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WO
WIPO (PCT)
Prior art keywords
interface
pass filter
impedance
low
transmission link
Prior art date
Application number
PCT/FI2000/000112
Other languages
English (en)
Inventor
Harri Elo
Original Assignee
Nokia Networks Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nokia Networks Oy filed Critical Nokia Networks Oy
Priority to AU26742/00A priority Critical patent/AU2674200A/en
Publication of WO2000048314A1 publication Critical patent/WO2000048314A1/fr
Priority to US09/913,576 priority patent/US6937719B2/en

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H11/00—Networks using active elements
    • H03H11/02—Multiple-port networks
    • H03H11/40—Impedance converters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
    • H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
    • H04M11/062—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors using different frequency bands for speech and other data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing

Definitions

  • the present invention relates generally to the implementation of a transmission connection via which both narrowband and broadband services are offered. More specifically, the invention relates to the separating of narrowband POTS/ISDN services from broadband services, particularly broadband services implemented with ADSL (Asymmetrical Digital Subscriber Line) technology. Narrowband services in this context denote services offered in the frequency range below the ADSL band.
  • ADSL Asymmetrical Digital Subscriber Line
  • Optical fibre is a self-evident choice as a transmission medium for a core network, since trunk connections usually require high transmission capacity, the transmission distances used are long, and ready routes are often available for cables. Also for subscriber connections (line between a local exchange and a subscriber) the situation is rapidly changing, since various services implemented with multimedia, requiring a high transmission rate, will be commonplace from the point of an individual consumer as well.
  • ADSL Asymmetrical Digital Subscriber Line
  • HDSL High bit rate Digital Subscriber Line
  • the rate of an ADSL transmission link from network to subscriber is in the order 2 - 6 Mbit/s and from subscriber to network in the order 32 - 640 kbit/s (mere control channel).
  • the data rate of an ADSL line is always n ⁇ 32 kbit s, where n is an integer.
  • the HDSL transmission technique relates to the transfer of a 2 Mbit s-level digital signal in a metal pair cable.
  • HDSL transmission is symmetric, that is, the transmission rate is the same in both directions.
  • ADSL seems at the moment to be the most promising technique for implementing broadband services, it will be used as an example of the access technique by means of which the services are offered.
  • the ADSL Forum has specified a generic network model for xDSL links; this is illustrated in Figure 1.
  • the device that connects to a subscriber line at the subscriber end is called ATU-R (ADSL Transmission Unit - Remote), and the device that connects to a subscriber line at the network end (e.g. at a local exchange) is called ATU-C (ADSL Transmission Unit - Central).
  • ATU-R ADSL Transmission Unit - Remote
  • ATU-C ADSL Transmission Unit - Central
  • ADSL modems or ADSL transceivers
  • the present invention employs frequency division multiplexing, in which narrowband and broadband services are separated from one another by a splitter or cross-over carrying out the frequency division of ADSL signals and narrowband signals.
  • the splitter can be a POTS/ADSL splitter PS or an ISDN/ADSL splitter IS.
  • the terminals TE at the end user can be of many different types, such as terminals TE1 of a cable TV network, personal computers TE2 or even ISDN phones TE3 if time division multiplexing is used.
  • Such service modules can in practice include Set Top Boxes, PC interfaces or LAN routers, for example.
  • a premises distribution network PDN located at the premises of the subscriber, connects the ATU-R to the service modules.
  • an access node AN constitutes a concentration point for narrowband and broadband data, at which point the traffic arriving from different service systems through different networks is concentrated.
  • the access node is located at the exchange of a telephone network, for example.
  • reference A denotes the part constituted by a private network
  • B the part constituted by a public network
  • C a network located at the premises of a subscriber (the telephones are naturally located at the subscriber).
  • ADSL services can be frequency multiplexed onto the same pair cable by means of a splitter.
  • Figure 2 illustrates a subscriber line divided between POTS and ADSL services, denoted with reference SL.
  • the splitter (PS1 or PS2) comprises two filter units: a low-pass filter unit LPF prevents the access of signals of the ADSL band (25 kHz...1.1 MHz) to the POTS interface 11 , and a high-pass filter unit HPF prevents the access of signals of the POTS band (0 Hz...4 kHz) to the ADSL interface 12.
  • the frequency division of the link is of the kind shown in Figure 3: signals relating to POTS or ISDN services are transferred at low frequencies, and ADSL signals are transferred at higher frequencies.
  • the splitter has a line port (P) connected to the subscriber line.
  • the low-pass filter unit is connected between the line port and the POTS interface 11
  • the high-pass filter unit HPF is connected between the line port and the ADSL interface 12.
  • Teleoperators determine the viability of filters by means of a reference impedance, which is defined so as to correspond to the actual impedance of the subscriber link as well as possible.
  • Figure 4 depicts a typical reference impedance Zref used by operators, comprising a resistance (R11 ) followed by a parallel connection of a resistance (R12) and a capacitor (C11 ).
  • R11 resistance
  • R12 resistance
  • C11 capacitor
  • the filter must provide a sufficiently good impedance match to the reference impedance in the voice band. A perfect impedance match is achieved when the output impedance of the generator concurs with the load impedance.
  • the load impedance is looked at through the filter. In such a case, the effective load impedance deviates from the reference impedance, since the filter unit can never be entirely transparent.
  • a filter unit can be implemented as a passive LC network (i.e., as a circuitry comprising windings and capacitors).
  • LC implementation seems to be the only feasible alternative.
  • this implementation is attended by significant problems, which will be described in the following.
  • a passive low-pass filter loads both the subscriber line and the POTS interface by its input impedance.
  • This impedance should equal the impedance of the subscriber line and the POTS interface as well as possible before the installation of the splitter, since in that case the splitter does not impair the matching of the POTS interface to the subscriber line.
  • the impedance of a passive filter cannot be designed independently of the other parameters, but the transfer function striven for and the load impedance set the boundary conditions for the impedance to be realized. Furthermore, sufficient isolation must be provided between the
  • the characteristic impedance Z' 0 that is visible when the subscriber line is seen through an LC filter is in practice at least somewhat dissimilar to the characteristic impedance Z 0 of the plain subscriber line.
  • the actual filter can be implemented in such a way as to exhibit a sufficiently correct input impedance.
  • Another alternative is to implement the filter in such a way that its input impedance clearly deviates from the ideal value, but the impedance matching is corrected by a discrete correction block.
  • Such a correction block is termed a Generalized Immittance Converter (GIC).
  • GIC Generalized Immittance Converter
  • the alternative to be selected for the implementation is mainly dependent on the standard specifications set by the teleoperators. Some teleoperators stipulate in their specifications that the impedance matching be effected by means of a discrete GIC block.
  • EP-0742972-B1 discloses a POTS splitter in which a passive filter (LC network) is used as a low-pass filter, but in addition to this, a two-way impedance correction is made by using two GIC blocks. More specifically, in the implementation disclosed in said publication the LC and GIC blocks have been used as shown in Figure 5, i.e. in such a way that the LC network 52 serving as a low-pass filter is placed between two GIC blocks 51. Hence, in this publication the starting-point is the idea that to make the impedance matching in each direction sufficiently good, the low-pass filter must be implemented as reciprocal, i.e., mirrored.
  • GIC block is a costly and sizeable circuit element, and hence the inclusion of two such substantially similar circuit elements will render the splitter expensive and large and result in a cumbersome practical implementation.
  • the input circuit of the GIC block will connect to line capacitively and the output circuit inductively.
  • a limited amount of transfer resistance is associated with the GIC block, which will result in an increase in the effective length of the POTS line in offhook state.
  • a limited amount of shunt impedance is also associated with the GIC block, which will load the line in offhook state in which the impedance is nominally infinite.
  • the GIC block is active, i.e. consumes power.
  • the idea of the invention is to compensate for the deterioration in service quality caused by the addition of the splitter asymmetrically by placing impedance conversion means wholly between the subscriber line-end interface of the passive low-pass filter and the POTS/ISDN interface.
  • the impedance matching can be effected either by using a single GIC block placed between the passive low-pass filter block and the POTS interface, or even entirely without a GIC block by providing the passive low- pass filter with separate resistances that afford an impedance correction effect through changing the characteristic impedance of the filter block.
  • the impedance matching can be restored with as good accuracy as possible to correspond to the situation before the installation of the ADSL, particularly as in practice even the strictest matching requirements can be met by using, in addition to one GIC block, the above-stated resistances in the passive low-pass filter block, by means of which the matching of the filter can be improved from the subscriber line side.
  • the invention is based on the idea that what is essential for maintaining the quality of service is the symmetricity of the connection, not that of the splitter (filter). Since the addition of a low-pass filter to the connection causes deterioration in the balance of the impedance bridge (will be described below) in the subscriber station, a correction to be carried out by means of a discrete GIC block does not afford any significant advantage on that side of the filter in which a two-wire/four-wire conversion is not carried out. Hence, no separate GIC block is needed on the subscriber line side of the filter block, but the impedance matching can be implemented with a single block on the side of the POTS interface, using the above-stated resistances in the filter block as an aid, when necessary.
  • Figure 1 illustrates the generic network model specified by the ADSL Forum
  • Figure 2 shows a subscriber line divided between POTS and ADSL services
  • Figure 3 shows the frequency division used in a transmission connection in accordance with the invention
  • Figure 4 illustrates the reference impedance used by operators, by means of which the viability of a splitter is estimated
  • Figure 5 illustrates a prior art impedance correction method
  • FIG. 6 illustrates prior art separation of transmission directions carried out in the subscriber connection
  • Figure 7 illustrates a filter topology in accordance with the invention for the low-pass filter of a POTS/ADSL splitter
  • Figure 8 illustrates a passive low-pass filter block used in the embodiment in accordance with Figure 7 in its generic form
  • Figure 9 illustrates a differential implementation of the filter block of Figure 8.
  • Figure 10 illustrates a possible implementation of the filter block
  • Figure 11 illustrates a generic 2-port circuit
  • Figure 12 illustrates the principle of implementation of an impedance-converting GIC
  • Figure 13 illustrates a practical implementation of the impedance-converting GIC in a unipolar case
  • Figure 14 illustrates the practical implementation of the GIC of Figure 13 in a differential case
  • Figure 15 illustrates the GIC block of Figure 14 when both its input and its output are inductively connected to line
  • Figures 16a and 16b illustrate practical examples of dimensioning the low-pass filter block.
  • the band division filtering required in xDSL technology must be realized in such a way that service quality will not appreci- ably deteriorate when the xDSL feature is added to the subscriber line.
  • the impedance of the filter must be matched as well as possible to the subscriber line.
  • the specifications of some operators stipulate that the impedance matching be carried out by means of a discrete GIC block.
  • the transmission directions are separated by means of an impedance bridge (hybrid). This principle has been illustrated in Figure 6, in which the impedance bridge is made up by impedances Z1 , Z2, Z3 and line impedance ZJine.
  • the microphone M of the telephone set is connected through amplifier A1 and impedance Z3 to line conductor L.
  • the terminal of impedance Z3 on the amplifier side is connected through impedances Z1 and Z2 to ground.
  • the common terminal of the two last- mentioned and the line conductor L form a receiving interface, which is connected through receiving amplifier A2 to earphone E.
  • the correct operation of the impedance bridge requires that it is loaded through a subscriber line that terminates with a remote-end bridge (whose implementation in principle is identical with that of the subscriber end and which is situated at a local exchange).
  • the solution in accordance with the invention is based on the idea that for the quality of the telephone connection, what is essential is the symmetry of the connection and not that of the filter, whereupon the implementation with two GIC blocks is based.
  • the low-pass filter When the low-pass filter is incorporated into the connection, it causes deterioration of the balance of the impedance bridge.
  • the impedance correction is implemented asymmetrically in the present invention in such a way that there is no separate GIC block on the subscriber line side of the filter, where no two-wire/four-wire conversion is carried out.
  • the solution in accordance with Figure 7 is used, in which the actual filtration is carried out in a passive low-pass filter block 72, which is typically an RLC network, and a GIC block 71 , wherewith the impedance matching is restored with as high accuracy as possible to correspond to the situation before the installation of the ADSL, is placed between the POTS interface and the low-pass filter block.
  • a GIC block is only provided on the POTS interface side of the low- pass filter block.
  • An exception to this is the first block (BN) seen from the subscriber line, in which no longitudinal capacitances are allowed. This is because the low-pass filter must have a high input impedance in the ADSL band.
  • the basic function, i.e. low-pass filtering is achieved with a combination of a longitudinal coil and a transverse capacitor.
  • a longitudinal capacitor By means of a longitudinal capacitor, on the other hand, attenuation can be added to a given frequency band.
  • longitudinal resistances RLi By means of longitudinal resistances RLi, the characteristic impedance of the filter can be shaped and thereby the impedance matching on the subscriber line side corrected, when necessary.
  • each block has been implemented by means of a transformer
  • the quantity of subblocks is used to influence the steepness of the filter.
  • Corresponding components have typically different values in the different subblocks.
  • Each subblock has at least one longitudinal coil, but the entire filter block nevertheless always has at least one longitudinal coil (transformer) and one transverse capacitor.
  • the GIC block on the side of the POTS interface is indispensable.
  • the low-pass filter block is implemented using the known filter design principles, but in addition impedance matching for the subscriber line side can be attended to by longitudinal resistances, if necessary. However, the necessity thereof is dependent on whether the GIC block is indispensable and if it is, how well the matching requirements can be met with a GIC block only.
  • Figure 10 illustrates an exemplary implementation of the low-pass filter block, having a total of three successive subblocks.
  • the first subblock comprises all the components stated above
  • the second subblock comprises all the other components except for longitudinal capacitors
  • the third subblock only comprises a longitudinal transformer.
  • the characteristic impedance of the filter has been shaped by means of longitudinal resistances RL1', RL1", RL2', RL2".
  • the characteristic impedance of a plain LC network is real, but it changes into complex if longitudinal resistances are introduced. In the following, two further practical design examples will be presented.
  • the impedance present on port 1 is equal to the load impedance on port 2 multiplied by a function of the complex frequency, which is independent of the load impedance.
  • a 2-port having such a chain matrix can be implemented by connecting a voltage source controlled by the voltage on port 2 between the ports in accordance with Figure 12.
  • Capacitance Cin has a high value so that in the voice band the capacitance can approximately be presumed as a short circuit, in which case the amplifier has a resistive input (in the voice band).
  • the feedback loop of the operational amplifier has an impedance Zf, which is a function of the complex frequency s, in which case a voltage V[(a+bs)/(c+ds)] is obtained at point P1 when V is the input voltage, where a and b are constants. This voltage is converted in transformer T2 to longitudinal format for the line.
  • the connection of Figure 13 adheres to the principle of Figure 12.
  • FIG. 14 illustrates such an implementation.
  • a current l B is obtained at the input of operational amplifier OPb, said current being proportional to the potential Vb in wire b.
  • operational amplifier OPa analog inversion is performed, and thus a current l A , proportional to the potential -Va when Va is the potential of wire a, is obtained at the output of the amplifier.
  • operational amplifier OPb these currents are added together to the feedback leg provided by impedance Zf, which gives a voltage of the above-described format at point P1.
  • the filter is implemented in such a way that in practice there is a finite impedance to the earth from the ground potential of the electronics, i.e., the electronics of the filter floats.
  • the resistances and capacitors of the input circuit of the GIC block are selected so that the asymmetry is negligible.
  • Figure 15 shows a GIC block in which both the input and the output circuit are inductively connected to line.
  • input capacitances Cin are not needed (the tapping point of the primary winding has capacitor C), and thus the resistances Rin are directly connected to the ends of the secondary winding of transformer T3.
  • Transformer T3 can be implemented highly symmetrically compared to discrete resistances and capacitors, and hence no special attention need to be paid to earthing arrangements when this topology is used.
  • this connection is not optimal either, as both the main in- ductance of transformer T3 and the capacitance of capacitor C must be remarkably high. In practice, this will result in physically large components.
  • Figures 16a and 16b show two practical dimensioning examples of the low-pass filter block.
  • a GIC block has been used (preferably in accordance with e.g. Figure 13), whereas in the case of Figure 16b the matching is attended to by an RLC network only.
  • the input capacitance 50 nF (which is naturally not fitted in the filter) of the ADSL modem is shown first as seen from the direction of the line. It has been presumed in the design that a twisted pair cable of a length of 3 km wherein the thickness of a single copper wire is 0.4 mm is used in the subscriber connection. Such a wire thickness is the most common in European telephone networks.
  • the GIC block may be of any known type. Such blocks have been disclosed for example in the European patent publication referred to above. It is true, however, that the practical drawbacks of a current GIC ( Figure 7 in the European publication) include a high surface area consumption (possible ring tone problem) and the fact that the symmetry problem will not be entirely eliminated otherwise than by the earth floating described above.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Telephonic Communication Services (AREA)
  • Interface Circuits In Exchanges (AREA)

Abstract

La présente invention concerne la mise en oeuvre de services bande étroite et bande large dans un réseau de télécommunication. Un coupleur réception est connecté à une liaison de transmission, ce coupleur réception comprenant un filtre passe-bas passif (72) connecté entre la liaison de transmission et une première interface (l1), un filtre passe-haut (HPF) connecté entre la liaison de transmission et une seconde interface (l2), et des organes discrets convertisseurs d'impédance (71) permettant d'adapter la première interface à l'impédance caractéristique de la liaison de transmission. Les organes convertisseurs d'impédance sont complètement situés entre l'interface du filtre passe-bas (72), du côté de la liaison de transmission, et la première interface, de sorte que l'adaptation de l'impédance requise par le filtre passe-bas puissent être mise en oeuvre d'une façon économique tout en maintenant la qualité du service.
PCT/FI2000/000112 1999-02-15 2000-02-15 Multiplexage et demultiplexage de services bande etroite et bande large dans une connexion de transmission WO2000048314A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU26742/00A AU2674200A (en) 1999-02-15 2000-02-15 Multiplexing and demultiplexing of narrowband and broadband services in a transmission connection
US09/913,576 US6937719B2 (en) 1999-02-15 2001-08-13 Multiplexing and demultiplexing of narrowband and broadband services in a transmission connection

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI990308 1999-02-15
FI990308A FI106682B (fi) 1999-02-15 1999-02-15 Kapea- ja laajakaistaisten palvelujen erotus siirtoyhteydellä

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US09/913,576 Continuation US6937719B2 (en) 1999-02-15 2001-08-13 Multiplexing and demultiplexing of narrowband and broadband services in a transmission connection

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002060085A2 (fr) * 2001-01-22 2002-08-01 Vacuumschmelze Gmbh & Co. Kg Ensemble filtre
WO2003037031A1 (fr) * 2001-10-22 2003-05-01 Infineon Technologies Ag Ensemble circuit repartiteur
FR2834835A1 (fr) * 2002-12-20 2003-07-18 Europe Adsl Leacom Fastnet Lab Filtre passe bas destine aux lignes telephoniques adaptees a la transmission adsl
DE10203221A1 (de) * 2002-01-28 2003-08-21 Siemens Ag Vorrichtung und Verfahren zur Vermeidung von Retrainigsvorgängen bei integrierter Voice- und xDSL- Datenübertragung ####
FR2848041A1 (fr) * 2002-11-29 2004-06-04 Europe Adsl Leacom Fastnet Lab Filtre passe bas avec asic destine aux lignes telephoniques adaptees a la transmission adsl
FR2855680A1 (fr) * 2003-05-26 2004-12-03 Europe Adsl Leacom Fastnet Lab Filtre passe bas pour filtrage de signaux adsl sur des lignes telephoniques modelisees par une impedance complexe
FR2864867A1 (fr) * 2004-01-05 2005-07-08 Europe Adsl Leacom Fastnet Lab Filtre destine aux lignes telephoniques adaptes a la transmission adsl
DE10153740B4 (de) * 2001-10-31 2006-05-24 Infineon Technologies Ag Verfahren und Vorrichtung zur Tiefpassfilterung
EP1783996A1 (fr) 2005-11-04 2007-05-09 Alcatel Lucent Diviseur ADSL avancé

Citations (2)

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Publication number Priority date Publication date Assignee Title
EP0677938A1 (fr) * 1994-04-14 1995-10-18 ALCATEL BELL Naamloze Vennootschap Dispositif de couplage de signaux
US5623543A (en) * 1994-02-01 1997-04-22 British Telecommunications Public Limited Company Two port signalling voltages filter arrangement

Patent Citations (2)

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Publication number Priority date Publication date Assignee Title
US5623543A (en) * 1994-02-01 1997-04-22 British Telecommunications Public Limited Company Two port signalling voltages filter arrangement
EP0677938A1 (fr) * 1994-04-14 1995-10-18 ALCATEL BELL Naamloze Vennootschap Dispositif de couplage de signaux

Non-Patent Citations (1)

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Title
JOHN COOK ET AL.: "ADSL and VADSL splitter design and telephony performance", IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, vol. 13, no. 9, December 1995 (1995-12-01), pages 1634 - 1642 *

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002060085A3 (fr) * 2001-01-22 2003-04-17 Vacuumschmelze Gmbh & Co Kg Ensemble filtre
WO2002060085A2 (fr) * 2001-01-22 2002-08-01 Vacuumschmelze Gmbh & Co. Kg Ensemble filtre
WO2003037031A1 (fr) * 2001-10-22 2003-05-01 Infineon Technologies Ag Ensemble circuit repartiteur
US7388885B2 (en) 2001-10-22 2008-06-17 Infineon Technologies Ag Splitter circuit
DE10153740B4 (de) * 2001-10-31 2006-05-24 Infineon Technologies Ag Verfahren und Vorrichtung zur Tiefpassfilterung
DE10203221A1 (de) * 2002-01-28 2003-08-21 Siemens Ag Vorrichtung und Verfahren zur Vermeidung von Retrainigsvorgängen bei integrierter Voice- und xDSL- Datenübertragung ####
FR2848041A1 (fr) * 2002-11-29 2004-06-04 Europe Adsl Leacom Fastnet Lab Filtre passe bas avec asic destine aux lignes telephoniques adaptees a la transmission adsl
WO2004051977A2 (fr) * 2002-11-29 2004-06-17 Laboratoire Europeen Adsl Leacom Fastnet Filtre passe bas destine aux lignes telephoniques adaptees a la transmission adsl.
WO2004051977A3 (fr) * 2002-11-29 2004-08-05 Europe Adsl Leacom Fastnet Lab Filtre passe bas destine aux lignes telephoniques adaptees a la transmission adsl.
EP1339209A1 (fr) * 2002-12-20 2003-08-27 Laboratoire Europeen ADSL Leacom Fastnet Filtre passe bas destiné aux lignes téléphoniques adaptées à la transmission ADSL
FR2834835A1 (fr) * 2002-12-20 2003-07-18 Europe Adsl Leacom Fastnet Lab Filtre passe bas destine aux lignes telephoniques adaptees a la transmission adsl
FR2855680A1 (fr) * 2003-05-26 2004-12-03 Europe Adsl Leacom Fastnet Lab Filtre passe bas pour filtrage de signaux adsl sur des lignes telephoniques modelisees par une impedance complexe
FR2864867A1 (fr) * 2004-01-05 2005-07-08 Europe Adsl Leacom Fastnet Lab Filtre destine aux lignes telephoniques adaptes a la transmission adsl
EP1558014A1 (fr) * 2004-01-05 2005-07-27 Laboratoire Europeen ADSL Leacom Fastnet Filtre ADSL
EP1783996A1 (fr) 2005-11-04 2007-05-09 Alcatel Lucent Diviseur ADSL avancé
US8165283B2 (en) 2005-11-04 2012-04-24 Alcatel Lucent Advanced ADSL splitter

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FI106682B (fi) 2001-03-15
FI990308A0 (fi) 1999-02-15
AU2674200A (en) 2000-08-29
FI990308A (fi) 2000-08-16

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