US 2003/0114112 A1Published application

Dynamic upstream attenuation for ingress noise reduction

AssigneeGeneral Instrument Corporation

InventorsJay Strater, Dean Stoneback, Kevin T. Chang

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Abstract

A dynamic arrangement for reducing the presence of ingress noise in the upstream signal path of a two-way cable system utilizes a variable attenuation element and amplifier disposed along the upstream signal path. The amplifier includes a bypass switch so that the amplifier may be switched in to or out of the upstream path. A signal processor associated with the communications gateway functions to calculate the upstream loss present at the gateway and control the operation of the attenuation element, amplifier and bypass switch accordingly. Upstream attenuation is selected to be as large as possible, yet still allow in-building cable devices to communicate with their associated head end (HE) receiver equipment, after accounting for maximum transmit limitations.

Claims8

Dependent claims

An arrangement for reducing the presence of ingress noise from a communications gateway, including an embedded cable modem, at a subscriber location, said communications gateway comprising an RF module containing separate upstream and downstream signal paths, the arrangement comprising

a variable attenuation element disposed in the upstream signal path in the RF module;
a signal amplifier, exhibiting predetermined gain, disposed in said upstream signal path in said RF module;
and
a bypass switch disposed at the input of said signal amplifier, said bypass switch for controlling the presence of said signal amplifier in said upstream signal path such that when said bypass switch is in the “open” position said signal amplifier is removed from said upstream signal path and when said bypass switch is in the “closed” position said signal amplifier is inserted in said upstream signal path;
and
a signal processor for calculating the value of upstream loss as used in attenuation and amplifier settings, said signal processor for controlling the operation of said variable attenuation element, said signal amplifier and said bypass switch so as to reduce the presence of ingress noise in the upstream signal path.

3 more elements

A method of reducing the presence of ingress noise in the upstream path of a bidirectional cable system at a communications gateway located at a subscriber premises, the method comprising the steps of:

calculating the upstream loss present at the communications gateway;
if the calculated loss is positive, bypassing an amplifier disposed in the upstream path and setting an upstream variable attenuation element to exhibit an attenuation equal to the calculated upstream loss value;
and
if the calculated loss is negative, inserting the amplifier along the upstream path, said amplifier exhibiting a predetermined positive gain value and setting an upstream variable attenuation element to exhibit an attenuation equal to the maximum of the sum of the predetermined positive gain value and the calculated upstream loss value, or zero.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 10/309,874Filed 4 Dec 2002
Priority: 4 Dec 2001
Published: 19 Jun 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

H04B 1/109
Means associated with receiver for limiting or suppressing noise or interference: by improving strong signal performance of the receiver when…
H04N 7/102
Adaptations for transmission by electrical cable: circuits therefor, e.g. noise reducers, equalisers, amplifiers
H04B
Transmission
H04N
Pictorial communication