Patent ID: 7480114
Filing Date: 2009-01-20
Classification: G11B

Abstract:
1. A synchronous servo channel for a data tape drive, comprising: a servo reader configured to read servo bursts from a data tape; a fixed-frequency clock; an analog-to-digital converter (ADC) operable to output signal samples at a sampling rate provided by the clock and coupled to receive a servo channel signal comprising servo bursts from the servo reader; an acquisition module having a first input coupled to receive a sequence of signal samples from the ADC at the sampling rate established by the clock and operable to generate initial servo channel parameters from the sequence of signal samples without a prior indication of the tape velocity or of the y-position of the tape; a timing-basis generator responsive to zero crossings of an interpolated servo channel signal, operating at a rate established by the clock, and operable to output a plurality of signals, including timing information for the generation of interpolated servo signal samples; a servo channel signal interpolator having a first input coupled to receive the sequence of signal samples from the ADC and a second input coupled to receive the timing information from the timing-basis generator for the generation of interpolated servo signal samples; an optimum longitudinal position (LPOS) detector having a first input coupled to receive an output from the servo channel signal interpolator and a second input coupled to receive at least one of the plurality of signals output from the timing-basis generator, the LPOS detector operable to detect and decode an LPOS symbol embedded in the servo bursts; an LPOS detection monitor operable to assign a reliability measure to the decoded LPOS symbol; and a channel parameter estimator initially responsive to the initial servo channel parameters from the acquisition module, the channel parameter estimator having a first input coupled to receive the sequence of signal samples from the ADC and a second input coupled to receive at least one of the signals output from the timing-basis generator, the channel parameter estimator operable to generate a tape velocity estimate and a y-position estimate from the sequence of signal samples output from the channel ADC.