US 2002/0176569 A1Published application

Hybrid circuit for a broadband modem

AssigneeAlcatel

InventorsHerman Joris Casier, Olivier Latte, Patrick Wouters, Daniel Sallaerts

Life of this patent

Estimating the term…

Loading patent…

Abstract

A hybrid circuit that couples a broadband modem to a POTS or ISDN telecommunication line (TL) and comprises a transformer bridge circuit (TBC) that includes a bridge circuit (BC). The bridge circuit is constituted by four legs of which a first (A) and a second (B) nodes, that do not belong to a same leg, are connected to the two outputs of a differential drive amplifier (DRV) that performs impedance synthesis. A first leg is made of a first impedance matching network (Zm1) connected between the second node (B) and a third node (C). A second leg is made of a first primary winding (TP1) of a transformer and is connected between the third (C) and the first (A) nodes. A third leg is made of a second impedance matching network (Zm2) connected between the first node (A) and a fourth node (D). A forth leg is made of a second primary winding (TP2) of the transformer and is connected between the fourth (D) and second (B) nodes. A secondary winding (TS) of the transformer is magnetically coupled to the first and the second primary windings and is electrically coupled to the telecommunication line. A first impedance divider (Zhin1, Zhout1) is connected between the third (C) and first (A) nodes and has a first central node (E), whilst a second impedance divider (Zhin2, Zhout2) is connected between the fourth (D) and second (B) nodes and has a second central node (F). A receive amplifier (RCV) has inputs connected to the first (E) and second (F) central nodes. The impedance matching networks (Zm1; Zm2) include various passive and reactive components that provides together an impedance value selected based upon the line impedance reflected into the primary windings (TP1; TP2) of the transformer. To perform the impedance synthesis, the drive amplifier (DRV) is a differential drive amplifier having feedback inputs (FB−, FB+) to which the third (C) and fourth (D) nodes are connected.

Hybrid circuit adapted to couple a broadband modem to a telecommunication line (TL), said hybrid circuit comprising a transformer bridge circuit (TBC) including a bridge circuit (BC) coupled between a drive amplifier (DRV) and a receive amplifier (RCV), and a transformer of which a secondary winding (TS) is electrically coupled to said telecommunication line,

said bridge circuit comprising first (A), second (B), third (C) and fourth (D) nodes interconnected via four legs,
a first leg (B-C) comprising a first impedance matching network (Zm1) coupled across said second (B) and third (C) nodes,
a second leg (A-C) comprising a first primary winding (TP1) of said transformer coupled across said first (A) and third (C) nodes,
a third leg (A-D) comprising a second impedance matching network (Zm2) coupled across said first (A) and fourth (D) nodes, and
a fourth leg (B-D) comprising a second primary winding (TP2) of said transformer coupled across said second (B) and fourth (D) nodes,
the secondary winding of said transformer being magnetically coupled to said first and second primary windings,
said drive amplifier having outputs (Out+, Out−) connected to said first and second nodes and being adapted to provide an output signal derived from a transmit signal received from said modem, and
said receive amplifier having inputs coupled to said third and fourth nodes and being adapted to provide a receive output signal to be applied to said modem,
characterized in that said drive amplifier (DRV) is a differential drive amplifier having feedback inputs (FB−, FB+) and being adapted to perform impedance synthesis,
in that said third (C) and fourth (D) nodes are respectively connected to a first (FB-) and to a second (FB+) of said feedback inputs,
and in that said bridge circuit (BC) further comprises
a first impedance divider (Zhin1, Zhout1) coupled between said first (A) and third (C) nodes, and having a first central node (E) to which a first input of said receive amplifier (RCV) is connected, and
a second impedance divider (Zhin2, Zhout2) coupled between said second (B) and fourth (D) nodes, and having a second central node (F) to which a second input of said receive amplifier is connected.

10 more elements

Facts

Application

10/097,013Filed 14 Mar 2002

Priority

EP 01400682.915 Mar 2001

Published

28 Nov 2002

Term ends

Not estimatedThe source records don’t support an estimate.

Classification5 codes

H04B 1/583
Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of…
H04L 27/0002
Modulated-carrier systems: analog front ends; means for connecting modulators, demodulators or transceivers to a transmission line
H04L 27/2601
Systems using multi-frequency codes: multicarrier modulation systems
H04B
Transmission

Abstract

Claims10