Abstract

We describe a technique that can be used to increase mark density by reducing track spacing. The technique can be understood by observing that, as track spacing is reduced, data signal zs contains an intertrack interference term Δi in addition to the ideal signal i₀, where i_s is given by Δi is commonly referred to as crosstalk. We generate a signal that is proportional to the derivative of Δi by a technique we call quadrant pupil detection (QPD). The QPD signal i_ϵ can be subtracted from the derivative of the data signal to yield which can be used for data detection. Alternatively, i_ϵ can be integrated and subtracted from i_s directly.

© 1996 Optical Society of America