Method and apparatus for mitigating radio frequency radiation from a microprocessor bus
AssigneeKyocera Wireless Corp.
InventorRobert B. Ganton
Life of this patent
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Abstract
A low-pass filter 10 on a microprocessor bus 22 for attenuating radio frequencies from digital signals travelling on the bus 22 from a microprocessor 12 to a peripheral device 20. An RC network is implemented as close as physically possible to the junction of the bus connection to microprocessor 12 and memory 14 to filter radio frequencies to an extent that limits radiation of these frequencies from the length of the bus 22. Wait states are adjusted as necessary to accommodate filtering of the digital signal that is transmitted over microprocessor bus 22.
Claims11
In a system including a peripheral, a microprocessor configured to adjust a wait state used to control the timing of communications between the microprocessor and the peripheral, a ground terminal, and a microprocessor bus for carrying digital signals between the microprocessor and the peripheral, a low-pass filter located in the signal path of the microprocessor bus between the microprocessor and the peripheral, said low-pass filter for attenuating radio frequencies from the digital signals traveling on the microprocessor bus.
In a system including a peripheral, a microprocessor configured to adjust a wait state used to control the timing of communications between the microprocessor and the peripheral, a ground terminal, and a microprocessor bus for carrying digital signals between the microprocessor and the peripheral, an apparatus for mitigating radio frequency interference from the microprocessor bus, said apparatus comprising:
- a first resistance in the signal path of the bus between the microprocessor and the peripheral;
- and
- a capacitance between a terminal of said first resistance and the ground terminal.
A method of mitigating radio frequency interference from a microprocessor bus, the method comprising:
- passing a digital signal pulse output by the microprocessor through a low-pass filter such that radio frequencies are attenuated from the pulse;
- and
- adjusting the wait state used to control the timing of communications between the microprocessor and a peripheral.
Dependencies are inferred from the claim text.