Editing Spread spectrum (section)

=== Method ===
In PCIe, USB 3.0, and SATA systems, the most common technique is downspreading, via [[frequency modulation]] with a lower-frequency source.<ref>{{cite web |title=Spread Spectrum Clocking |url=https://www.microsemi.com/document-portal/doc_download/135439-white-paper-spread-spectrum-clocking |website=Microsemi}}</ref> Spread-spectrum clocking, like other kinds of [[dynamic frequency change]], can also create challenges for designers. Principal among these is clock/data misalignment, or [[clock skew]]. A [[phase-locked loop]] on the receiving side needs a high enough bandwidth to correctly track a spread-spectrum clock.<ref name="IM2013">{{cite web |author1=Item Media |title=Spread Spectrum Clock Generation – Theory and Debate |url=https://interferencetechnology.com/spread-spectrum-clock-generation-theory-and-debate/ |website=Interference Technology |date=19 March 2013}}</ref>

Even though SSC compatibility is mandatory on SATA receivers,<ref>{{cite web |title=CATC SATracer / Trainer Application Note: Spread Spectrum Clocking |url=https://cdn.teledynelecroy.com/files/appnotes/satracer_ssc_appnote.pdf |website=CATC |access-date=20 May 2023 |date=July 2, 2003}}</ref> it is not uncommon to find expander chips having problems dealing with such a clock. Consequently, an ability to disable spread-spectrum clocking in computer systems is considered useful.<ref>[http://www.thomas-krenn.com/de/wiki/Raid_Controller_erkennt_Western_Digital_Raid_Edition_III_HDDs_nicht Western Digital Raid Edition III HDDs werden vom RAID Controller nicht erkannt] (Thomas Krenn Wiki)</ref><ref>[http://www.intel.com/cd/channel/reseller/emea/deu/support/lcs/faq/334571.htm Intel Speichersystem SS4000-E: Festplatten, wie beispielsweise die Western Digital WD2500JS SATA, werden nicht erkannt. Woran liegt das?] (Intel Reseller-Center)</ref><ref>{{Webarchive |url=https://web.archive.org/web/20100429194819/http://seagate.custkb.com/seagate/crm/selfservice/search.jsp?DocId=214011&NewLang=en |title=SSC Toggle Utility – Barracuda 7200.9 |date=2010-04-29}} (Seagate Knowledge Base)</ref>