EMI proof battery pack for night vision goggles
First Claim
1. In a battery pack for night vision goggles that are employed in the cockpit of an aircraft, where RF fields of several hundred volts/meter can be present, the battery pack having at least one external lead that picks up RF signals, but not having an effective ground plane, the improvement comprising shunt means for shunting RF signals picked up by said at least one external lead, said shunt means having an input coupled to said at least one external lead;
- and dissipating means, having a resistive component, coupled to an output of said shunt means, for dissipating electromagnetic energy of the RF signals provided on said output of said shunt means.
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Accused Products
Abstract
An improved battery pack for night vision goggles is employed in the cockpit of an aircraft, where RF fields of several hundred volts/meter are present. The improved battery pack includes a shunt circuit for shunting RF signals picked up by any external leads from the battery pack, and a resistor for dissipating electromagnetic energy from the RF signals shunted by the shunt circuit.
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Citations
15 Claims
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1. In a battery pack for night vision goggles that are employed in the cockpit of an aircraft, where RF fields of several hundred volts/meter can be present, the battery pack having at least one external lead that picks up RF signals, but not having an effective ground plane, the improvement comprising shunt means for shunting RF signals picked up by said at least one external lead, said shunt means having an input coupled to said at least one external lead;
- and dissipating means, having a resistive component, coupled to an output of said shunt means, for dissipating electromagnetic energy of the RF signals provided on said output of said shunt means.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A battery pack for night vision goggles, comprising:
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voltage means, for providing a first operating potential on a first output and a second operating potential on a second output; low battery indicator means, responsive to said first output of said voltage means, for determining when said operating potential provided by said first output of said voltage means is at a low level, said low battery indicator means including a voltage comparator having a first input coupled to said first output of said battery means, a second input coupled to a source that provides a reference voltage, a third input coupled to a reference potential, and an output that is coupled to said third input when said voltage at said first input of said voltage comparator is less than said reference voltage at said second input of said voltage comparator; an LED mounted on the night vision goggles; external leads coupling said battery pack to said night vision goggles, including a first external lead for providing said first operating potential to said night vision goggles, a second external lead connected to a first terminal of said LED, and a third external lead coupling a second terminal of said LED to said reference potential; a resistor that dissipates electromagnetic energy provided by RF signals picked up by said external leads, said resistor having a first terminal that is coupled to said first terminal of said LED by said second external lead; and shunt means for shunting RF signals, including an inductance, coupled between said first output of said voltage means and said first external lead, said inductance functioning to block said RF signals from entering said first output of said voltage means, a first capacitance, coupled between said first external lead and said second output of said voltage means, for shunting said RF signal, transistor means having its current controlled path connected between said second output of said voltage means and a second terminal of said resistor, and having its base responsive to an output of said low battery indicator means, a second capacitance, coupled across said controlled current path of said transistor means, for shunting said RF signals, and a third capacitance, coupled across said second and third external leads, for shunting said RF signals. - View Dependent Claims (12, 13, 14, 15)
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Specification