Transferring digital subscriber connection signals via a coaxial cable

Patent metadata

Field	Value
Publication number	US-11949536-B2
Application number	US-202118249260-A
Country	US
Kind code	B2
Filing date	Oct 7, 2021
Priority date	Oct 29, 2020
Publication date	Apr 2, 2024
Grant date	Apr 2, 2024

Abstract

A method for transmitting digital subscriber connection signals to an interface of an end user via a coaxial cable includes: supplying, by a distribution point unit (DPU), first balanced subscriber connection signals to the coaxial cable by a first transformation; coupling unbalanced subscriber connection signals into the coaxial cable into a lower frequency range of an overall frequency range; attenuating, by means of a filtering device, a reflection of the unbalanced subscriber connection signals in the coaxial cable; a second transformation of the unbalanced subscriber connection signals into second balanced subscriber connection signals by means of a balun device assigned to the interface, wherein the input impedance of the filtering device is adjusted with respect to reflections from the direction of the customer terminal output; and separately making the second balanced subscriber connection signals available at the customer terminal output.

First claim

The invention claimed is:

1. A method for transmitting digital subscriber connection signals to an interface of an end user via a coaxial cable, wherein the coaxial cable has an overall frequency range configured for transmitting TV signals to the interface of the end user in an upper frequency range of the overall frequency range, wherein the interface comprises a customer terminal output, wherein the method comprises the following steps:
supplying, by a distribution point unit first balanced subscriber connection signals to the coaxial cable by a first transformation, directed toward the customer terminal output, of the first balanced subscriber connection signals into unbalanced subscriber connection signals by means of a distribution point balanced-to-unbalanced transformer device (balun device);
coupling the unbalanced subscriber connection signals into the coaxial cable into a lower frequency range of the overall frequency range, wherein the lower frequency range is below the upper frequency range without any overlap;
attenuating, by means of a filtering device, a reflection of the unbalanced subscriber connection signals in the coaxial cable;
a second transformation, directed toward the customer terminal output, of the unbalanced subscriber connection signals into second balanced subscriber connection signals by means of a balun device assigned to the interface, wherein the input impedance of the filtering device is adjusted with respect to reflections from the direction of the customer terminal output; and
separately making the second balanced subscriber connection signals available at the customer terminal output.

2. The method according to claim 1 , wherein the balun device assigned to the interface comprises a choke device and a transformer device, wherein the choke device is passed through first and the transformer device is passed through next in the direction of the customer terminal output, wherein the input impedance of the filtering device is adjusted by a compensation capacitor between the filtering device and the balun device assigned to the interface, wherein the compensation capacitor is arranged between the filtering device and the choke device.

3. The method according to claim 2 , wherein the input impedance of the filtering device is adjusted using impedance transformation in that twin lines having a characteristic impedance that is different from the characteristic impedance of the coaxial cable are used to implement the choke device wherein the impedance transformation is implemented on the basis of a short length of the twin lines, wherein twin lines having a characteristic impedance in the range between 45Ω and 65Ω are used.

4. The method according to claim 2 , wherein the impedance compensation is carried out by means of the choke device and the transformer device, in addition to the compensation capacitor, wherein the choke device comprises an annular core and an inductance per winding of between 1.0 μH and 1.2 μH, and wherein the annular core is wrapped in wire in the form of a twin line, wherein the wire is a multi-insulated wire and in particular has a characteristic impedance of between 65Ω and 85 Ω.

5. The method according to claim 2 , wherein the transformer device is configured to transform impedances in a range between 65Ω and 85Ω into an impedance of between 95Ω and 105 Ω.

6. The method according to claim 2 , wherein the choke device is a common-mode choke, wherein the choke device comprises 10 windings and a common-mode inductance of 110 μH; and/or
wherein the transformer device comprises magnetizing inductances of 263 μH on a 75-Ω side and of 353 μH on a 100-Ω side.

7. The method according to claim 1 , wherein, for a plurality of coaxial cables, the first transformation, directed toward the customer terminal output, comprises converting a plurality of balanced digital subscriber connection signals into a plurality of unbalanced digital DSL signals, wherein the distribution point balun device located at the DPU is a multiple balun unit, wherein the plurality of balanced digital subscriber connection signals have an impedance in a first impedance range and the plurality of unbalanced digital subscriber connection signals have an impedance in a second impedance range, and/or
wherein the second transformation, directed toward the customer terminal output, causes the unbalanced digital subscriber connection signals having an impedance in the second impedance range to be converted into second balanced subscriber connection signals having an impedance in the first impedance range and in a frequency range between 1 MHz and 444 MHz, wherein the first impedance range is in the range between 95Ω and 105Ω, and the second impedance range is in the range between 70Ω and 80Ω.

8. The method according to claim 1 , wherein the unbalanced subscriber connection signals are coupled into the coaxial cable at an impedance in a second impedance range using 75-Ω TV bidirectional couplers, wherein the coaxial cable in particular is part of a coaxial TV star topology of a building.

9. The method according to claim 1 , wherein the lower frequency range includes subscriber connection signals up to around 212 MHz and/or the upper frequency range includes the TV signals above around 262 MHz; or
wherein the lower frequency range includes subscriber connection signals up to around 424 MHz and/or the upper frequency range includes the TV signals above around 524 MHz.

10. The method according to claim 1 , wherein, at the customer terminal output of the interface, input reflection attenuation of more than or exactly 22 dB is carried out up to at least 350 MHz.

11. The method according to claim 1 , wherein the balun device assigned to the interface implements transverse conversion loss of at least 25 dB between 2 MHz and 1 GHz; and/or
the balun device assigned to the interface implements attenuation of S21, the forward transmission coefficient, of less than 4 dB between 2 MHz and 1 GHz.

12. Interface of an end user for use in a method according to claim 1 , for transmitting digital subscriber connection signals to the interface via the coaxial cable, wherein the coaxial cable has an overall frequency range configured for transmitting TV signals to the interface of the end user in the upper frequency range of the overall frequency range, wherein the interface comprises the customer terminal output, wherein, with respect to unbalanced subscriber connection signals which are in the lower frequency range of the overall frequency range, said lower frequency range being below the upper frequency range without any overlap, and which are coupled into the coaxial cable, the interface is configured such as to cause:
a reflection of the unbalanced subscriber connection signals in the at least one coaxial cable to be attenuated by means of a filtering device, and
the second transformation, directed toward the customer terminal output, of the unbalanced subscriber connection signals into second balanced subscriber connection signals to be carried out by means of the balun device, assigned to the interface, wherein the input impedance of the filtering device is adjusted with respect to reflections from the direction of the customer terminal output, and
the second balanced subscriber connection signals to be separately made available at the customer terminal output,
wherein, in addition to a TV output, the interface comprises the customer terminal output and is configured to make TV signals available at the TV output in the upper frequency range and to make balanced subscriber connection signals available at the customer terminal output in the lower frequency range.

1

Assignees

• Deutsche Telekom Ag

Inventors

• Muggenthaler Peter
• Loeffelholz Marko
• Tudziers Christoph
• Leppla Ralph

Classifications

• H04L12/2898 Primary

  Subscriber equipments (DSL modems H04M11/062; cable modems H04L12/2801) · CPC title

• H04B3/21

  using a set of bandfilters · CPC title

• H04B3/02

  Details · CPC title

• H04N7/106

  for domestic distribution · CPC title