Methods and apparatus for measuring servo address

专利名称：Methods and apparatus for measuring servo

address mark distance in a read channelusing selective fine phase estimate

发明人：Jeffrey P. Grundvig,Viswanath

Annampedu,Xun Zhang

申请号：US12847676申请日：20100730公开号：US08049982B1公开日：20111101

专利附图：

摘要：Methods and apparatus are provided for measuring servo address mark

distance in a read channel using selective fine phase estimates. A distance between servoaddress marks (SAMs) in servo data of a magnetic recording media can be computed byobtaining a count of a number of time intervals between SAM patterns; obtaining aplurality of fractional phase estimates; selecting at least one of the plurality of fractionalphase estimates as a selected fractional phase estimate based on a selection criteria; andcombining the count and the selected fractional phase estimate to compute the distance.The fractional phase estimates can include a first fractional phase estimate having a lowerresolution and higher accuracy in the presence of frequency errors relative to a secondfractional phase estimate and wherein the second fractional phase estimate has moreresolution and lower accuracy in the presence of the frequency errors relative to the firstfractional phase estimate. The selection criteria can comprise a frequency errorthreshold.

申请人：Jeffrey P. Grundvig,Viswanath Annampedu,Xun Zhang

地址：Loveland CO US,Schnecksville PA US,Westford MA US

国籍：US,US,US

代理机构：Ryan, Mason & Lewis, LLP

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