Conexant Systems, Inc.

Broadcom Corporation

Rockwell International Corporation

Silicon Laboratories Inc.

Raphael Rahamim

Thomas Grey Beutler

Vladimir Oksman

Eric Floyd Riggert

John S Walley

Steven A Gronemeyer

Kenneth David Ko

Jamal Haque

P Michael Henderson

Joel D Peshkin

Edward S Zuranski

Ganning Yang

Yongbing Wan

Kenneth Scott Walley

Frank Sacca

Shrenik P Patravali

Anthony A Tzouris

Frederic M Stubbe

David O Anderton

Ismail I Eldumiati

Don L Harmer

Robert W Frankland

Dale E Folwell

James Bunde Villadsen Skov

Daniel J Marz

Alberto Mantovani

Jacques Mathe

Stanton Christopher Renna

Russell Brian Schott

Nuno F Paulino

Brian D Stroud

Jason B Brent

A method for estimating electrical length of a loop in a digital subscriber line (DSL) system begins by estimating an electrical length of a loop for each of a plurality signals based on a known power level of the plurality of signals, a known frequency for each of the plurality of signals, and a received power level for each of the plurality of signals. The method continues by processing the plurality of estimated electrical lengths in accordance with a function corresponding to characteristics of the loop to produce a determined electrical length.

Transmit power adjustment based on estimated electrical length of a loop

An analog front end. The analog front end comprises a converter configured to convert a differential input signal to a single-ended input signal, and convert a single-ended output signal to a differential output signal. And a transformer configured to couple the differential input signal from a twisted pair telephone line to the converter, and couple the differential output signal from the converter to the twisted pair telephone line.

Single ended analog front end

A digital subscriber line (DSL) communication system that utilizes the high frequency band of a standard telephone line does not require the use of a plain old telephone service (POTS) splitter in the resident's home, which provided isolation between the POTS frequency band (0 to 4 kHz) and the DSL frequency band. A digital subscriber line modem utilizes either constant envelope modulation or quadrature amplitude modulation for outputting DSL signals upstream to a central office. When a telephone in the resident's home is detected as being off-hook, then the constant envelope modulation is used by the DSL modem in order to lessen the intermodulation product distortion that results in audible noise heard by a user of the telephone. When the telephone is on-hook, then another type of modulation, such as QAM, is used to maximize the upstream data rate capability in the DSL frequency band, since any noise generated by the QAM is not a problem due to the non-use of the POTS frequency band.

Modulation switching for DSL signal transmission

The present invention establishes a communications link between a central office (CO) modem and a customer premise equipment (CPE) modem. The CO modem then evaluates the performance of the communications link. Impairments on the communications link are identified based on the evaluation results. Next, adjustment parameters for improving the performance of the communications link are determined. The CPE modem is then modified in accordance with the determined adjustment parameters to establish an adjusted communications link between the CO modem and the CPE modem. In this way, impairments such as bridged taps and cross-talk can be avoided.

Method and system for reducing cross-talk and avoiding bridged taps

A modem utilizing a DAA having line side circuitry including a telephone network interface and system side circuitry including a host system interface. The line side circuitry and the system side circuitry are separated by a high voltage isolation barrier. In accordance with the invention, the high voltage isolation barrier and other DAA circuitry are configured such that data and control information may be communicated between the system side circuitry and the line side circuitry using a serialized digital communication protocol. In one embodiment of the invention, the line side circuitry of the modem includes detection and measurement circuitry that is programmable to measure or establish electrical characteristics (e.g., tip/ring voltage and loop current) of the telephone line interface connection. Command information for the programmable circuitry is multiplexed with data communicated across the high voltage isolation barrier. Interrupt signals and information for synchronizing communications between the system side circuitry and the line side circuitry may also comprise a portion of the serialized datastream.

Data access arrangement utilizing a serialized digital data path across an isolation barrier

To adjust transmit power of a DSL modem, an estimated electrical length of a loop is first determined when a 1DSL modem at a 1location transmits a plurality of signals to a 2DSL modem at a 2location. Each of the signals transmitted by the 1DSL modem have a known frequency and are transmitted at a known power level. Upon receiving the signals, the 2DSL modem determines the received power level for each of the signals. The 2DSL modem then estimates an electrical length of a loop between the 1and 2DSL modems for each of the signals received. The 2DSL modem then processes a plurality of estimated electrical lengths in accordance with a function to produce a determined electrical length. Having determined the electrical length, the 2DSL modem adjusts its transmit power accordingly.

Adjustment of transmit power based on an estimated electrical length of a loop

In an electronic inductor circuit, an operational amplifier drives the base of the electronic inductor transistor, and receives negative feedback from the emitter of the transistor. The transistor and operational amplifier combine to form a voltage-controlled, current source (VCCS) with respect to the loop current. A voltage divider connected across the rectified Tip and Ring voltage (or another node of the circuit at an equivalent voltage) provides a DC reference to the positive input of the operational amplifier, so that the line current automatically increases with an increase in line voltage. A capacitor couples the transmit signal driver to the positive input of the operational amplifier. This electronic inductor circuit can be driven using a low voltage supply and provides sufficient linearity for high-speed modem applications.

Electronic inductor with transmit signal telephone line driver

A circuit board capacitor structure operable as a high voltage isolation barrier in communication circuitry. Capacitor electrodes form a capacitive structure directly on a printed circuit board's opposing sides. The PCB substrate intermediate the electrodes functions as the capacitive structure's dielectric material. The capacitor electrodes are sized such that the electrodes' area and the substrate's dielectric properties create the desired capacitance. Alternatively, a multi-layered PCB may be utilized where layer(s) is/are used to form the capacitive structure. The circuit board capacitor may couple communication circuitry located on the PCB's various sides. The circuit board capacitor operates as a high voltage isolation barrier in data access arrangements, separating line and system side circuitry. Further, the high voltage isolation barrier may include multiple circuit board capacitors to realize differential communications and/or multiple datapaths. The capacitor structure can be flexibly arranged to minimize PCB real estate and be more cost-effective than discrete capacitors.

Circuit board capacitor structure for forming a high voltage isolation barrier

A method for configuring a multi-port digital subscriber line (DSL) modem, the method begins by utilizing frequency bands of a single DSL channel to support a data communication when loop length of the single DSL channel and data rate of the data communication are favorable. The method continues by utilizing some of the frequency bands of the single DSL channel and frequency bands of at least one other DSL channel to support the data communication when the loop length of the single DSL channel is unfavorable or the data rate of the data communication is unfavorable.

Configurable DSL modem for high bit rates

A configurable multi-port modem includes a plurality of hybrids, a plurality of receivers, a plurality of transmitters, and a switching module. Each of the plurality of hybrids is operably coupled to provide 2 to 4 wire coupling for a corresponding one of a plurality of twisted pairs that are coupled to the configurable multi-port modem. Each of the plurality of receivers is operably coupled to convert inbound DSL signals into inbound data. Each of the plurality of transmitters is operably coupled to convert outbound data into outbound DSL signals. The switching module is operable to couple at least one of the plurality of hybrids to at least one of the plurality of receivers and to at least one of the plurality of transmitters based on a configuration control signal.

Configurable multi-port modem to achieve a high bit rate in a DSL system

A telephone line interface circuit is disclosed having intelligent line current control that can adjust to the various requirements of worldwide telephone systems (DC masks), and/or can reduce the power consumed by the interface circuit. A controller reads a voltage value and based on the theoretical model of a telephone line network, and the expected current/voltage characteristic, as dictated by the appropriate DC mask. The controller sets the line current (via an output voltage) to an optimum value and causes the line voltage to adjust so as to comply with the DC mask and/or minimize power dissipation in the circuit.

Telephone line interface circuit with intelligent line current and voltage control

In an electronic inductor circuit, an operational amplifier drives the base of the electronic inductor transistor, and receives negative feedback from the emitter of the transistor. The transistor and operational amplifier combine to form a voltage-controlled current source (VCCS) with respect to the loop current. A voltage divider connected across the rectified Tip and Ring voltage (or another node of the circuit at an equivalent voltage) provides a DC reference to the positive input of the operational amplifier, so that the line current automatically increases with an increase in line voltage. A capacitor couples the transmit signal driver to the positive input of the operational amplifier. This electronic inductor circuit can be driven using a low voltage supply and provides sufficient linearity for high-speed modem applications.

A high voltage isolation barrier includes first and second capacitors, each having a first terminal connected to a system-side input signal source. A first diode is connected between second terminals of the first and second capacitors, and a second diode is connected to the second terminal of the first capacitor and to a first terminal of a third capacitor. Application of an alternating polarity squarewave across the first terminals of the first and second capacitors results in generation of a line side voltage on the third capacitor and in transfer of a clock signal at the squarewave frequency across the isolation barrier to the line side.

Growing community of inventors

Orange, CA, United States of America

Raphael Rahamim