NONLINEAR DISTORTION IN HELICAL-SCAN TAPE-RECORDERS

Nonlinear distortion in high frequency high density tape recording is investigated. Experiments were conducted on a helical-scan tape transport at a single channel data rate of 150 Mbps using MIG heads and metal particle tape. Nonlinear distortion was characterized by extracting the echo from the dipulse response of a pseudo-random sequence recording. It is found that a transition is sharpened and shifted earlier by the immediately preceding transition. A precompensation scheme using the combination of record current overshoot and zero-crossing delay can eliminate almost all the nonlinear distortion. Bit error rate improvement was demonstrated in recordings employing this pre-compensation scheme.