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US 6,720,756 B2Granted
Modifying acoustic emissions of fans
AssigneeIntel Corporation
InventorsHarry G. Skinner, Duane G. Quiet, Willem M. Beltman
Life of this patent
Estimating the term…
Abstract
In one embodiment to reduce unwanted acoustic fan noise, the control signal for a computer system cooling fan is modulated so that the acoustic noise power spectral density of the fan has a bandwidth greater than when the control signal is constant.
Claims9
An apparatus comprising:
- a fan having a fan speed responsive to a control signal, the fan generating acoustic noise in response to the control signal, the acoustic noise having a power spectral density;
- and
- a modulator to provide the control signal such that the power spectral density has a greater bandwidth than when the fan is operating under a constant control signal;
- wherein the modulator provides the control signal such that the control signal is periodic with period T, the period T having a first time interval T1 and a second time interval T2 where T=T1+T2, and wherein the control signal is increasing over the first time interval and is decreasing over the second time interval.
1 more element
A computer system comprising:
- a fan to exchange air in the computer system, the fan having a fan speed responsive to a control signal, the fan generating acoustic noise in response to the control signal, the acoustic noise having a power spectral density;
- and
- a modulator to provide the control signal such that the power spectral density has a greater bandwidth than when the fan is operating under a constant control signal;
- wherein the modulator provides the control signal such that the control signal is periodic with period T, the period T having a first time interval T1 and a second time interval T2 where T=T1+T2, and wherein the control signal is increasing over the first time interval and is decreasing over the second time interval.
1 more element
A method to modify noise from a fan, the fan having a fan speed responsive to a control signal, the method comprising:
- providing a time varying control signal to the fan such that the noise has a power spectral density having a larger bandwidth than when the fan is operating under a constant control signal;
- wherein the control signal is periodic with period T, the period T having a first time interval T1 and a second time interval T2 where T=T1+T2, and wherein the control signal is increasing over the first time interval and is decreasing over the second time interval.
Dependencies are inferred from the claim text.