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US 6,310,953 B1Granted
Subscriber circuit
AssigneeFujitsu Limited
InventorsKazuhiro Yoshida, Kenji Takato
Life of this patent
Estimating the term…
Abstract
In a subscriber circuit implementing the analog system, the 2B1Q system and the ping-pong system, a signal processing unit is divided into a signal output unit for outputting a signal for transmission and a bias unit for providing a voltage, the signal output unit being implemented by an amplifier unit characterized by a low withstand voltage and a broadband characteristic, and the bias unit is implemented by an amplifier unit characterized by a high withstand voltage and a narrowband characteristic.
Claims7
A subscriber circuit comprising:
- a DC/DC converter selectively providing a dc voltage from a primary side to a secondary side;
- an electronic choke circuit, coupled in series between an output of the DC/DC converter and a subscriber line blocking an analog signal;
- a voltage and current detection circuit directly detecting a voltage and a current of the subscriber line, and producing an output;
- and
- a controller, respondive to the output of said voltage and current detection circuit, controlling the DC/DC converter to produce a voltage commensurate with a power feed resistance.
2 more elements
A subscriber circuit comprising:
- a DC/DC converter selectively providing a dc voltage from a primary side to a secondary side;
- an electronic choke circuit, coupled in series between an output of the DC/DC converter and a subscriber line blocking an analog signal;
- a voltage and current detection circuit directly detecting a voltage and a current of the subscriber line, and producing an output;
- and
- a controller, responsive to the output of said voltage and current detection circuit, controlling the DC/DC converter to produce a voltage commensurate with a power feed resistance,
- a switch, coupled between the primary side and the secondary side of the DC/DC converter, putting the primary side and the secondary side to one of a floating state and a non-floating state.
3 more elements
A subscriber circuit comprising:
- a DC/DC converter selectively providing a dc voltage from a primary side to a secondary side;
- an electronic choke circuit, coupled in series between an output of the DC/DC converter and a subscriber line blocking an analog signal;
- a voltage and current detection circuit directly detecting a voltage and a current of the subscriber line, and producing an output;
- and
- a controller, responsive to the output of said voltage and current detection circuit, controlling the DC/DC converter to produce a voltage commensurate with a power feed resistance,
- wherein a first transformer for an analog signal and a second transformer for a digital signal are coupled in series, the first and second transformers remain coupled in series when the subscriber circuit is used as an analog subscriber circuit, and one of the first and second transformers is short-circuited when the subscriber circuit is used as a digital subscriber circuit.
3 more elements
Dependencies are inferred from the claim text.