Line interface with gain feedback coupled matching impedance

• US 20020151280A1
• Filed: 01/25/2002
• Published: 10/17/2002
• Est. Priority Date: 02/01/2001
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Sabouri, Faramarz, Kenney, John G. Jr., Guido, John P.
• Granted Patent: US 6,925,172 B2
• Time in Patent Office: Days
• US Class Current: 455/80
• CPC Class Codes: H04L 25/0266 Arrangements for providing Galvanic isolation, e.g. by means of magnetic or capacitive coupling
• CPC Class Codes: H04L 25/0278 Arrangements for impedance matching
• CPC Class Codes: H04L 25/028 Arrangements specific to the transmitter end
• CPC Class Codes: H04L 27/0002 analog front ends; means for connecting modulators, demodulators or transceivers to a transmission line duplex arrangements H04L5/143

Abstract

A transceiver system is disclosed for use in a telecommunication system. The transceiver system includes a transmission circuit including a transmitter input coupled to an input of a transmission amplifier, a receiver circuit including a receiver output coupled to an output of a receiver amplifier, and a transmission line interface circuit that is coupled to an output of the transmission amplifier and to an input of the receiver amplifier. The transmission line interface circuit includes a matching impedance that is directly coupled to a feedback path of the transmission amplifier and that terminates the transmission line of the transceiver system.

Claims

1. A transceiver system for use in a telecommunication system, said transceiver system comprising:

a transmission circuit including a transmitter input coupled to an input of a transmission amplifier;

a receiver circuit including a receiver output coupled to an output of a receiver amplifier; and

a transmission line interface circuit coupled to an output of said transmission amplifier and to an input of said receiver amplifier, said transmission line interface circuit including a matching impedance that is directly coupled to a feedback path of said transmission amplifier and that terminates the transmission line of said transceiver system.

2. The system as claimed in claim 1, wherein said transmission line interface circuit includes a primary transformer winding that is connected in series with the output of the transmission amplifier.

3. The system as claimed in claim 1, wherein said transmission circuit provides a first order high pass filter function.

4. A transceiver system for use in a telecommunication system, said transceiver system comprising:

a transmission circuit including a differential transmitter input coupled to a differential input of a transmission amplifier;

a receiver circuit including a differential receiver output coupled to a differential output of a receiver amplifier; and

a transmission line interface circuit coupled to a differential output of said transmission amplifier and to a differential input of said receiver amplifier, said transmission line interface circuit including a single impedance matching network that terminates the transmission line of said transceiver system.

5. The system as claimed in claim 4, wherein said transmission line interface circuit includes two primary transformer windings, each of which is connected in series with one each path in the differential output of the transmission amplifier.

6. The system as claimed in claim 4, wherein said transmission circuit provides a first order high pass filter function.

7. A line driver circuit for use in a transceiver system, said circuit comprising a transmission line interface circuit that is coupled to an output of a transmission amplifier and to an input of a receiver amplifier, said transmission line interface including a single impedance matching network that terminates a transmission line of the transceiver system.

8. A transceiver system for use in a telecommunication system, said transceiver system comprising:

a transmission circuit including a differential transmitter input coupled to a differential input of a transmission amplifier;

a receiver circuit including a differential receiver output coupled to a differential output of a receiver amplifier; and

a transmission line interface circuit coupled to a differential output of said transmission amplifier and to an differential input of said receiver amplifier, said transmission line interface circuit including a matching impedance that is directly coupled to a feedback path of said transmission amplifier and that terminates the transmission line of said transceiver system.

9. The transceiver system as claimed in claim 8, wherein said transmission circuit includes a dual negative feedback network.

10. The transceiver system as claimed in claim 8, wherein said dual negative feedback network increases a relatively small impedance of the matching network to a larger line driver output impedance to match the characteristic impedance of the transmission line of said transceiver system.