Experimental study of amplitude asymmetry effects in perpendicular recording

In this paper, the amplitude asymmetry effects on playback waveforms in a perpendicular recording system are characterized in the time domain utilizing three different recording patterns. New recording patterns are developed to reduce the baseline shift induced by measurements through ac-coupled electronics. Advanced single-pole type heads with giant magnetoresistive playback sensors and double-layer perpendicular media are utilized. The experimental results indicate that the new recording patterns show advantages in better characterization of the playback amplitude asymmetry. The system performance of the bit-error rate (BER) is evaluated utilizing an advanced PRML channel for perpendicular recording. The experimental results indicate that BER correlates well with the playback signal asymmetry of the new recording pattern.