Texas Instruments Corporation

Adam M Chellali

Michael Oliver Polley

Yaqi Cheng

Alan Gatherer

Walter Y Chen

A multi-line ADSL modem () and network () whereby the multi-line ADSL modem () has connections to several ADSL modems () at a central office (CO) () through a master loop (), shared loops (), and/or broadcast loops (). The master loop () provides the basic connection between the multi-line ADSL modem () and the CO modem () at the central office () while maintaining regular telephone service. The shared loops allow the multi-line ADSL modem to share the transmission capacity with other modems. The multi-line ADSL modem is able to receive broadcast data from the central office where several loops are configured as a broadcast loop for downstream transmission only, but which can also be configured for upstream communication transmission only or in combination with downstream transmission to provide bi-directional broadband communications.

Multi-line ADSL modem

In a splitterless Digital Subscriber Line (DSL) modem , a receiver architecture ( ) that permits monitoring of harmonics within the upstream channel of a DSL connection. The receiver ( ) can detect the harmonics by monitoring the harmonics in some empty tones or specified tones. A threshold can be set to differ the normal noise power and harmonics power in those empty or specified tones. When a POTS device ( ) coupled to same wire line pair ( ) as the DSL modem ( ) goes off-hook, the DSL modem ( ) can switch from the normal state to an off-hook state in which the harmonics are reduced to minimum by transmitting only the upper sub-band tones of the upstream transmission channel at reduced power levels.

Splitterless modem using harmonics reduction

A splitterless DSL modem (,) with an integrated off-hook detector (,) prevents data loss and/or disconnections as a voiceband device (,) coupled to the same transmission line (,) transition between steady states. The splitterless DSL modem (,) include a DSP (,), an interface (,) to a twisted pair wire line (,), signal converters (,), and various filters (,). The off-hook detector circuit (,) can be coupled to the interface (,) on the analog side of the DSL modem (,) or on the digital side of the signal converters (,).

Splitterless modem with integrated off-hook detector

A method is described for reducing computational requirements during idle transmission in remote access systems incorporating digital subscriber line (DSL) modems, including asymmetrical DSL (ADSL) systems. Processing power is saved during idle transmission by generating an idle signal using low-complexity techniques. The generated idle signal is made spectrally compatible with xDSL systems, and a non-disruptive signaling scheme is used to indicate to the far-end receiver the transition between idle to active or active to idle status. A technique is presented that modulates the phase of the pilot tone to signal status transitions to the remote receiver. The computational complexity at the receiver is reduced because fill demodulation and decoding is not required to determine that an idle signal is being transmitted.

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Richardson, TX, United States of America

Adam M Chellali