Quoting from the Wikipedia article on Spread Spectrum:
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The usefulness of this method as a means to reduce real-life interference problems is often debated, as it is perceived that spread-spectrum clocking hides rather than resolves higher radiated energy issues by simple exploitation of loopholes in EMC legislation or certification procedures. This situation results in electronic equipment sensitive to narrow bandwidth(s) experiencing much less interference, while those with broadband sensitivity, or even operated at other higher frequencies (such as a radio receiver tuned to a different station), will experience more interference.
FCC certification testing is often completed with the spread-spectrum function enabled in order to reduce the measured emissions to within acceptable legal limits. However, the spread-spectrum functionality may be disabled by the user in some cases. As an example, in the area of personal computers, some BIOS writers include the ability to disable spread-spectrum clock generation as a user setting, thereby defeating the object of the EMI regulations. This might be considered a loophole, but is generally overlooked as long as spread-spectrum is enabled by default.”
Why are there no actual hardware-mitigated EMI signals (such as via capacitors)—would that not be good marketing for some “extra stable clocks” with low EMI? There are plenty of enthusiast computer builders who are also audiophiles to some extent, for example.
What’s the true downside to just disabling the Spread Spectrum settings in the BIOS—is the level of EMI potentially harmful to health, or is the interference also going to affect, say, WiFi connection quality or anything else?
Spread spectrum - Wikipedia
en.wikipedia.org
”
The usefulness of this method as a means to reduce real-life interference problems is often debated, as it is perceived that spread-spectrum clocking hides rather than resolves higher radiated energy issues by simple exploitation of loopholes in EMC legislation or certification procedures. This situation results in electronic equipment sensitive to narrow bandwidth(s) experiencing much less interference, while those with broadband sensitivity, or even operated at other higher frequencies (such as a radio receiver tuned to a different station), will experience more interference.
FCC certification testing is often completed with the spread-spectrum function enabled in order to reduce the measured emissions to within acceptable legal limits. However, the spread-spectrum functionality may be disabled by the user in some cases. As an example, in the area of personal computers, some BIOS writers include the ability to disable spread-spectrum clock generation as a user setting, thereby defeating the object of the EMI regulations. This might be considered a loophole, but is generally overlooked as long as spread-spectrum is enabled by default.”
Why are there no actual hardware-mitigated EMI signals (such as via capacitors)—would that not be good marketing for some “extra stable clocks” with low EMI? There are plenty of enthusiast computer builders who are also audiophiles to some extent, for example.
What’s the true downside to just disabling the Spread Spectrum settings in the BIOS—is the level of EMI potentially harmful to health, or is the interference also going to affect, say, WiFi connection quality or anything else?
