Cable access device and method
First Claim
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1. An access device, comprising:
- an input port comprising means for connecting to a first portion of a coaxial cable;
an output port comprising means for connecting to a second portion of said coaxial cable;
means for isolating an AC power signal from an RF signal;
a transformer for deriving a DC voltage from said isolated AC power signal, said transformer comprising a primary winding and a secondary winding; and
transformer control circuitry comprisinga switch, said switch alternately connecting or disconnecting said primary winding to a current source,means for generating a switch control signal, said switch control signal having an independent duty cycle and transfer cycle period, respectively,duty cycle control circuitry comprising means for increasing said duty cycle in response to a decrease in said DC voltage, and decreasing said duty cycle in response to an increase in said DC voltage, andtransformer reset circuitry comprising means for initiating an energy transfer cycle across said transformer in response to detecting the end of a previous energy transfer cycle.
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Abstract
An access device having an input port for connecting to an upstream section of a coaxial distribution cable and an output port for connecting to a downstream section of a coaxial distribution cable, and provides isolation of an RF communication signal from an AC power signal for access by subscriber network service equipment. The access device also includes power conditioning of the AC signal to provide a DC operating voltage over a separate output to operate the respective subscriber network service equipment.
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Citations
19 Claims
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1. An access device, comprising:
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an input port comprising means for connecting to a first portion of a coaxial cable; an output port comprising means for connecting to a second portion of said coaxial cable; means for isolating an AC power signal from an RF signal; a transformer for deriving a DC voltage from said isolated AC power signal, said transformer comprising a primary winding and a secondary winding; and transformer control circuitry comprising a switch, said switch alternately connecting or disconnecting said primary winding to a current source, means for generating a switch control signal, said switch control signal having an independent duty cycle and transfer cycle period, respectively, duty cycle control circuitry comprising means for increasing said duty cycle in response to a decrease in said DC voltage, and decreasing said duty cycle in response to an increase in said DC voltage, and transformer reset circuitry comprising means for initiating an energy transfer cycle across said transformer in response to detecting the end of a previous energy transfer cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In a broadband distribution network transporting a relatively high frequency RF signal and a relatively low frequency AC power signal, respectively, over a coaxial cable, an access device, comprising:
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an input port comprising means for connecting to a first portion of the coaxial cable; an output port comprising means for connecting to a second portion of the coaxial cable; diplexer circuitry for isolating the AC power signal from the RF signal; means for splitting the RF signal onto a first internal RF path and a second RF internal path, respectively; an RF output port connected to said second internal RF path; a transformer for supplying a DC voltage derived from the isolated AC power signal, said transformer comprising a primary winding and a secondary winding; a DC power port connected to said secondary winding; and transformer control circuitry comprising a switch, said switch alternately connecting or disconnecting said primary winding to a current source, means for generating a switch control signal, said switch control signal having an independent duty cycle and transfer cycle period, respectively, duty cycle control circuitry comprising means for increasing said duty cycle in response to a decrease in said DC voltage, and decreasing said duty cycle in response to an increase in said DC voltage, and transformer reset circuitry comprising means for initiating an energy transfer cycle across said transformer in response to detecting the end of a previous energy transfer cycle. - View Dependent Claims (12, 13, 14, 15)
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16. A coaxial cable access device, comprising:
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circuitry for isolating an AC power signal from an RF signal carried over a coaxial cable; a transformer for deriving a DC voltage from the isolated AC power signal, said transformer having a primary winding and a secondary winding; and transformer control circuitry comprising a switch, said switch alternately connecting or disconnecting said primary winding to a current source, means for generating a switch control signal, said switch control signal having an independent duty cycle and transfer cycle period, respectively, duty cycle control circuitry comprising means for increasing said duty cycle in response to a decrease in said DC voltage, and decreasing said duty cycle in response to an increase in said DC voltage, and transformer reset circuitry comprising means for initiating an energy transfer cycle across said transformer in response to detecting the end of a previous energy transfer cycle. - View Dependent Claims (17, 18, 19)
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Specification