Spectral contours for optimum signal detection

Data reliability for high-density recording is determined by both amplitude and phase margins at the signal detector after channel equalization. The spectral contour of the equalizer dictates the actual channel performance. Identified is a new group of transcendental functions, whose time and frequency responses are consistently superior to the established cosine-raised-power family. The method of formulating these functions is described. Their time- and frequency-domain properties are analyzed and compared. An optimum channel design example for a 3380E head/disk interface is demonstrated. This work broadens the basic understanding of channel equalization from which practical designs using discrete components or CCD SAW devices can be targeted objectively.