A modified cosine equalization effective for equalizing both amplitude and phase has been developed with a simple circuit. It slims asymmetrical read-back waveforms in digital magnetic recording devices more effectively than without phase equalization.

This letter describes a highly sensitive method for detecting contact between a head slider and disk medium. It is shown to provide 10 dB or greater improvement in the signal to noise ratio (SNR) from the small piezoelectric transducer attached to the head slider by using a new frequency mixer circuit.

A new write current equalization technique achieved by means of a simple write data operation is presented. This technique nearly doubles the write channel speed and makes it possible to realize a high data transfer rate read/write channel in digital magnetic recording.