US 6,661,634 B2 · Digital subscriber line alternating current EMI/RFI broadband noise eliminator

Abstract

The present invention provides an apparatus and method for filtering electrical power to and from an electrical appliance to reduce or eliminate electromagnetic interference (EMI) and radio frequency interference (RFI). In one embodiment, an electrical outlet strip apparatus is provided for interconnection between an AC power source and an electrical appliance that provides transient voltage surge suppression for the appliance while substantially reducing or eliminating EMI from the AC power source from reaching the appliance. Additionally, the apparatus reduces or eliminates EMI produced by the appliance from propagating into the AC power system. The apparatus and method utilize a multistage EMI filter to filter the electrical power. In particular, the electrical power is filtered in a broadband range associated with digital subscriber line (DSL) systems to provide for improved DSL system performance.

Claims16

Dependent claims

An outlet strip apparatus for filtering electromagnetic interference (EMI) from an appliance prior to said EMI being conducted into an AC power source, said apparatus comprising:

a first input line, a second input line and a ground line for interconnection with said AC power source;
a plurality of outlets for interconnecting said apparatus to at least one said electrical appliance, each said outlet having at least a first, second and third conductor connected to said first input line, second input line and ground line, respectively;
at least one voltage surge absorption element disposed between said AC power source and said outlets, said element directly attached between at least two of said first input line said second input line and said ground line;
a first set of EMI filters interconnected in series with said first input line including first and second capacitors interconnecting said first input line to said second input line and at least one inductor disposed between said capacitors;
and
a second set of EMI filters interconnected in series with said second input line and parallel with said first set of EMI filters, said second set of filters including at least one inductor disposed between said capacitors.

3 more elements

A method for filtering electromagnetic interference (EMI) from an electrical appliance to prevent said EMI from being conducted into an AC power system while providing transient voltage surge suppression for said electrical appliance, said method comprising the steps of:

interconnecting between an AC power source and an electrical appliance a multi-stage EMI filter enclosed within a metallic casing and comprising first and second EMI filters interconnected in series, and a transient voltage surge suppression element;
diverting transient voltages from incoming electricity from said AC power source having a voltage amplitude greater than a predetermined level such that said transient voltages by-pass said electrical appliance;
passing incoming electricity from said AC power source through said first and second EMI filters on a first input line to attenuate EMI contained within said incoming electricity prior to said electricity reaching said electrical appliance, wherein said first and second filters include first and second capacitors interconnecting said first input line to a second input line and at least one inductor disposed between said capacitors;
and
passing returning electricity from said electrical appliance through said first and second EMI filters on said second input line including at least one inductor disposed between said first and second capacitors such that EMI generated by said appliance is attenuated prior to re-introduction into said AC power source.

2 more elements

Dependencies are inferred from the claim text.

Digital subscriber line alternating current EMI/RFI broadband noise eliminator

Life of this patent

Digital subscriber line alternating current EMI/RFI broadband noise eliminator

Life of this patent

Abstract

Claims16