Fan speed control extends fan service life and decreases acoustic airflow noise and average fan current. The most efficient way to implement fan speed control is to use low frequency pulse width modulation (PWM). However, PWM fan speed control can sometimes introduce unwanted acoustic noise at a frequency equal to that of the PWM itself. This is especially noticeable when PWM control is used with higher operating current (>300 mA) fans and at low operating speeds. This document discusses the source of this acoustic noise and a method to suppress it.
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Re: There is a trojan pc virus here today.
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It still seems like there's some suspicious code on this site.
Maybe the trojan has damaged some scripts so they crash IE and give errors
in other browsers...
47 minutes ago
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