Experimental Study of Asymmetrical Waveform in Digital Recording

Waveform distortion reduces the phase detection margin in digital magnetic recording systems. Experimental and theoretical investigations into the relation between recording characteristics and waveform distortion of a thin-film head and a sputtered ¿-Fe2O3 disk were performed. Recording current and waveform distortion were measured after the DC-erase, in both directions. It was found that magnetic recording waveform distortion is related to the overwrite characteristics, such that the overwrite value must be maintained at a minimum of 30 dB to keep waveform distortion within 2 ns.