Gap effects in head field distributions and the replay process in longitudinal recording

Head field distributions have been predicted using the formulae originally derived by Fan (1961). These have been used in the prediction of output voltage waveforms in digital recording which may, in appropriate circumstances, exactly reflect head field distributions. In this work output voltage waveforms have been used to verify: (1) the validity of the `reciprocity¿ approach to predicting outputs, (2) the cal-culated field distributions, and (3) the state of current knowledge of the replay process. Particular attention has been focused on the role of the head gap length whose influence on various aspects of the replay process has not been fully investigated previously.