Equalizer design based on diffraction analysis

A design procedure is described that determines the optimum frequency chara cteristics of an equalizer, considering the intersymbol interference (ISI) and crosstalk, under the influence of the tilt of the disk substrate. A sca lar-wave diffraction model was employed to calculate the readout signals. A finite impulse response (FIR) filter was assumed for the equalizer. The ji tter was calculated as a function of the equalizer parameters, and the equa lizer parameters were determined so that the calculated jitter took its min imum value. The entire process of the equalizer design was performed on an computer, an d the resultant characteristics were similar to those determined through ex periments. Therefore, the method provides a useful tool for the basic desig n of optical disk systems.