Error rate drift caused by rubbing noise in ferrite read heads

Some combinations of DDS-3 tape drive and cassette experience a rapid increase in error rate, followed by a gradual spontaneous recovery, when a section of tape is repeatedly used. This behaviour is caused by a change in the level of rubbing noise resulting from changes to the surface of the read head. This paper describes an investigation into the nature of this noise, and in particular the effect of head-tape speed on its frequency spectrum. In some cases, standing-wave vibrations in the head structure are excited by periodic ripple features that form on the surface of the ferrite read heads.