Noise reduction in same-gap servo in frequency-based servo tape systems

Abstract

Noise in a same-gap, frequency-based servo tape system is reduced by applying correlated noise factors, generated during calibration, to filtered data write signals. The resulting noise values are subtracted from filtered servo signals, at frequencies Fand F, to generate first and second noise-compensated servo signals at frequencies Fand F. In one embodiment, the Fand Fdata signals are filtered through two SOBP filters which output the magnitudes of the signals. The Fand Fservo signals are similarly filtered. In another embodiment, the Fand Fdata signals are filtered through two Goertzel filters which output the real and imaginary components of the signals and the Fand Fservo signals are similarly filtered through two other Goertzel filters. Correlated noise factors are applied to the outputs of the write data Goertzel filters and the results subtracted from the corresponding outputs of the servo Goertzel filters.