Reduced-Complexity Common-Mode Noise Cancellation System For DSL
First Claim
1. A noise cancellation system, comprising:
- a first transformer having an input side and an output side, the input side having first and second taps coupled to a communication service provider and further having a center tap;
a first digital subscriber line (xDSL) modem having an input coupled to the output side of the first transformer and an output coupled to customer premises equipment (CPE) for providing an xDSL signal to the CPE;
a second transformer having an input side and an output side, the input side having first and second taps coupled to a communication service provider and further having a center tap;
a second, xDSL modem coupled to the output side of the second transformer; and
a third transformer having an input side and an output side;
the input side of the third transformer having one tap coupled to the center tap of the first transformer, and a second tap coupled to the center tap of the second transformer;
the output side of the third transformer coupled to the first and second xDSL modems to reduce noise in the xDSL signal provided to the CPE.
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Accused Products
Abstract
A noise cancellation system has a first transformer with an input side and an output side, the input side having first and second taps coupled to a signal provider, and a center tap providing a first common-mode voltage signal. A first digital subscriber line (xDSL) modem has an input coupled to the output side of the first transformer and an output coupled to customer premises equipment (CPE) for providing an xDSL signal to the CPE. A second transformer has an input side and an output side, the input side having first and second taps coupled to a signal provider, and a center tap providing a second common-mode voltage signal. A second xDSL modem is coupled to the output side of the second transformer. The difference between the first and second common-mode voltage signals is provided to at least one of the first and second xDSL modems to flier out noise from the xDSL signal provided by that modem.
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Citations
21 Claims
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1. A noise cancellation system, comprising:
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a first transformer having an input side and an output side, the input side having first and second taps coupled to a communication service provider and further having a center tap; a first digital subscriber line (xDSL) modem having an input coupled to the output side of the first transformer and an output coupled to customer premises equipment (CPE) for providing an xDSL signal to the CPE; a second transformer having an input side and an output side, the input side having first and second taps coupled to a communication service provider and further having a center tap; a second, xDSL modem coupled to the output side of the second transformer; and a third transformer having an input side and an output side;
the input side of the third transformer having one tap coupled to the center tap of the first transformer, and a second tap coupled to the center tap of the second transformer;the output side of the third transformer coupled to the first and second xDSL modems to reduce noise in the xDSL signal provided to the CPE. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13)
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11. A noise cancellation system, comprising:
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a first transformer having an input side and an output side, the input side having first and second taps coupled to a communication service provider and further having a center tap; an xDSL modem having an input side coupled to the output side of the first transformer and an output side coupled to customer premises equipment (CPE) for providing an xDSL signal to the CPE; and a second transformer having an input side with first and second taps, the first tap being coupled to the center tap of the first transformer and the second tap being coupled to a terminated wire pair; the second transformer having an output side coupled to the xDSL modem to reduce noise in the xDSL signal provided to the CPE. - View Dependent Claims (14, 15)
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16. A noise cancellation system, comprising:
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a first transformer having an input side and an output side, the input side having first and second taps coupled to a signal provider and further having a center tap and providing a first common-mode voltage signal; a first digital subscriber line (xDSL) modem having an input coupled to the output side of the first transformer and an output coupled to customer premises equipment (CPE) for providing an xDSL signal; a second transformer having an input side and an output side, the input side having first and second taps coupled to a signal provider and further having a center tap and providing a second common-mode voltage signal; a second xDSL modem coupled to the output side of the second transformer; means for taking the difference between the first and second common-mode voltage signals; and means for providing the difference to at least one of the first and second xDSL modems to filter out noise from the xDSL signal provided by that at least one modem. - View Dependent Claims (17, 18, 19, 20, 21)
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Specification