US 6,321,384 B1 · Noise reduction in cable return paths

Abstract

A method of reducing noise and ingress in cable return paths is disclosed in which the return frequency spectrum is divided into two regions; one frequency region being for transmissions from in-home devices such as television settops and personal computers, and another frequency region being for transmissions from communications devices called coaxial termination units located between the drop cable and the home coaxial wiring. By locating blocking filters between the drop cable and home coaxial wiring, undesirable signals emanating in the home in the second part of the return spectrum are prevented from entering the cable return system. The location of the blocking filter reduces the noise in the second part of the return spectrum substantially and allows the establishment of reliable telecommunications services on the cable return in such second part of the return spectrum. The blocking filters can be incorporated into the coaxial termination unit and the bandwidth of such filters varied from the head-end to allow more or less bandwidth to be used by in-home devices.

Claims12

Dependent claims

A method for reducing effects of ingress noise signals in a cable return system from a subscriber location to a central station, said return system having a common transmission path for first and second sub-bands of a return frequency band and wiring at said subscriber location having a tendency to pick up ingress signals extending in frequency through both sub-bands of said return frequency band, said method comprising the steps of:

receiving first communications signals from a first source through subscriber location wiring for transmission over said common transmission path within a portion of said first sub-band;
receiving second communications signals from a second source for transmission over said common transmission path within said second sub-band;
attenuating substantially all signal energy received from said subscriber location wiring in said second sub-band;
and
thereafter combining signals from both said first and said second sources for transmission over said common transmission path, substantially eliminating adverse effects of ingress signals from said subscriber location wiring upon communications signals from said second source transmitted over said common transmission path.

2 more elements

A combination for reducing effects of ingress noise signals in a cable return system from a subscriber location to a central station, said return system having a common transmission path for first and second sub-bands of a return frequency band and wiring at said subscriber location having a tendency to pick up ingress signals extending through both sub-bands of said return frequency band, said combination comprising:

first means for receiving communications signals from a first source through subscriber location wiring for transmission over said common transmission path within a portion of said first sub-band;
second means for receiving communications signals from a second source for transmission over said common transmission path within said second sub-band;
frequency selective filtering means connected to said first receiving means for attenuating substantially all signal energy received from said subscriber location wiring in said second sub-band;
and
coupling means connected to said first receiving means and to said filtering means for combining, subsequent to such attenuation, signals from said first and second sources for transmission over said common transmission path, substantially eliminating adverse effects of ingress signals from said subscriber location wiring upon communication signals from said second source transmitted over said common transmission path.

2 more elements

Dependencies are inferred from the claim text.

Noise reduction in cable return paths

Life of this patent

Noise reduction in cable return paths

Life of this patent

Abstract

Claims12