Development of MICROMV magnetic recording system

Summary form only given. We applied an MR head to the helical-scan consumer-use camcorder, and developed the new format named MICROMV. The head is an SAL biased AMR head and the medium is Co-CoO metal evaporated tape. Reproduced output level and impedance noise of the MR head were compared with those of the inductive head with a laminate structure. The result indicates that the carrier-to-noise ratio of MR head is +10 dB more than that of the inductive head at a wavelength of 0.29 /spl mu/m. The micro track profile of MR head was investigated and it became clear that not only reproducing sensitivity but also amplitude asymmetry varies as track position. In order to compensate amplitude asymmetry, we adopted a nonlinear circuit in which second harmonic distortion is fed back and its response converges within 50 /spl mu/s. We have successfully demonstrated a stable reproducing signal in the helical-scan tape drive. Thus the MICROMV format, which records one hour MPEG2 picture on a small cassette of 12 cc volume, is of practical use.