Patent ID: 7365929

Claim:
A method for operating a synchronous servo channel in a data tape drive in which a loaded tape has a velocity, a lateral (y) position relative to a servo element and a longitudinal position (LPOS) relative to an end of the tape, the method comprising: acquiring initial servo channel parameters from a sequence of signal samples output from a servo channel analog to digital converter (ADC) without a prior indication of the tape velocity or of the y-position of the tape; generating a timing basis for servo channel signal interpolation from zero crossings of an interpolated servo channel signal, whereby timing information is extracted despite unequally spaced servo bursts comprised in the servo channel signal; generating a tape velocity estimate and a y-position estimate from the sequence of signal samples output from the channel ADC; detecting and decoding an LPOS symbol encoded in the servo bursts; and monitoring LPOS detection and assigning a reliability measure to the decoded LPOS symbol.