Gap-null free spectral response of asymmetric ring heads for longitudinal and perpendicular recording

The head field distribution and the signal reproducibility of asymmetric ring heads at several large inclination angles are examined. It is shown that the asymmetric ring heads with large inclination can generate sharp spike-like sensitivity functions and a good smooth spectral-response curve which has no gap-nulls up to very high k(=2π/λ) values for both perpendicular and longitudinal recording modes. Due to the sharpness in the sensitivity function distribution, the phase angles of the readout voltage vary linearly with k. The importance of symmetry and sharpness in the sensitivity distribution function is discussed in relation to the reading process. It is concluded that an asymmetric ring head with a 30° inclination angle from the horizontal is very appropriate for both high-density perpendicular and longitudinal recording