Method and system for reducing radiated energy emissions in computational devices
First Claim
1. A method for reducing electromagnetic emissions from a computational device, comprising:
- providing within a substrate having a conductive trace, at least one capacitance region including a portion of said conductive trace and a conductive material, wherein said capacitance region operates, when signals having at least one of a rise time and a fall time in a range of approximately less than 200 picoseconds are transmitted on said trace, substantially as a capacitor for routing current from the trace toward another path in the substrate;
wherein;
(a1) said conductive material extends adjacently to said trace for a distance less than a length (LTr) of the trace required for carrying an entire signal corresponding to one of the rise time or the fall time; and
(a2) said conductive material is electrically isolated from the trace.
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Accused Products
Abstract
A method and system for reducing the release of high frequency electromagnetic energy into the environment is disclosed, wherein local regions of distributed capacitance are embedded within a printed circuit board (PCB) and adjacent the PCB conductive traces act as low pass filters and thus increase the rise and/or fall times occurring on such traces. The present invention increases very short rise and/or fall times (e.g., 200 picoseconds or less) without degrading or detrimentally affecting other signal characteristics. The present invention does not substantially affect the voltage amplitude and does not affect the bit period when lengthening the rise and/or fall time. Also, the present invention does not induce any timing jitter that may cause synchronization problems within the system.
16 Citations
21 Claims
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1. A method for reducing electromagnetic emissions from a computational device, comprising:
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providing within a substrate having a conductive trace, at least one capacitance region including a portion of said conductive trace and a conductive material, wherein said capacitance region operates, when signals having at least one of a rise time and a fall time in a range of approximately less than 200 picoseconds are transmitted on said trace, substantially as a capacitor for routing current from the trace toward another path in the substrate; wherein; (a1) said conductive material extends adjacently to said trace for a distance less than a length (LTr) of the trace required for carrying an entire signal corresponding to one of the rise time or the fall time; and (a2) said conductive material is electrically isolated from the trace. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An apparatus having reduced electromagnetic emissions, comprising:
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a substrate having a conductive trace; at least one capacitance region adjacent to said conductive trace, said capacitance region including a portion of said conductive trace and a conductive material, wherein the at least one capacitance region operates, when signals having at least one of a rise time and a fall time in a range of approximately less than 200 picoseconds are transmitted on said trace, substantially as a capacitor for routing current from the trace toward another path in the substrate; wherein; (a1 ) said conductive material extends adjacently to said trace for a distance less than a length (LTr) of the trace required for carrying an entire signal corresponding to one of the rise time or the fall time; (a2) when said capacitance region is operable, said current passes through said conductive material; and (a3) said conductive material is electrically isolated from the trace. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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21. An apparatus having reduced electromagnetic emissions, comprising:
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a substrate means for containing a conductive trace means, wherein the conductive trace means carries a conductive signal; at least one capacitance region means adjacent to said conductive trace means, said at least one capacitance region including a portion of said conductive trace and a conductive material, wherein the at least one capacitance region means operates, when signals having at least one of a rise time and a fall time in a range of approximately less than 200 picoseconds are transmitted on said conductive trace means, substantially as a capacitor for routing current from the conductive trace means toward another path in the substrate means; wherein; (a1) extends adjacently to said trace for a distance less than a length (LTr) of the trace required for carrying an entire signal corresponding to one of the rise time or the fall time; (a2) said current passes through a portion of said capacitance region different from said trace means; and (a3) said portion is electrically isolated from the trace.
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Specification