A design method for optimum equalization in magnetic recording with partial response channel coding

Equalization is of such importance as to dominate linear density in magnetic recording when partial response channel coding is employed. This paper describes an advanced design method for optimum equalization in Interleaved NRZI recording by means of a transversal equalizer. Error rate analysis proceeds through a series expansion. This is done in order to consider the tradeoff between equalizing error and equalizer output noise, which has been neglected in conventional design. Key input data for the design are readback pulse shape, noise power spectrum, and linear density. The results of the design are given as optimum tap number and optimum tap gain. Analysis through application of this method makes it possible to clarify the following. The optimum tap number is 8 to 14. The optimum equalizer produces about a 1.4 times linear density improvement in comparison with a conventional 4-tap transversal equalizer. An about 1.5 times linear density improvement compared with the