Detecting Marks Recorded as Extended One Half Wavelengths
Original Publication Date: 1980-Dec-01
Included in the Prior Art Database: 2005-Feb-14
In magnetic recording, demarcation between recording areas, identification of track rotational position on disks and longitudinal position on tapes as well as readback clock resynchronization patterns often employ what is termed as extended one-half wavelengths for indicating a fiducial mark on a record medium. Such extended one-half wavelengths are used because of their relatively high energy content which yields a relatively low susceptance to noise. As such extended one-half wavelengths increase in length, perturbations in signal readback may cause error conditions, and adjacent signals may be perturbed to a point for indicating a false mark. Accordingly, it is desired to provide a detection circuit which accommodates such signal perturbations and identifies error conditions in a reliable manner.