Derivation of analytical solution for confocal push-pull signals and improved confocal push-pull detection method using signal processing

We clarified the inherent characteristics of the confocal push-pull (CPP) m ethod of detecting tracking-error signals for an optical disk player before . We reported that CPP signals strongly depend on the parameters of the opt ical disk systems such as the groove/land ratio (duty ratio) and focus cond itions, although CPP signals are very stable in the face of the lens displa cement. In order to obtain stable tracking-error signals, it is necessary t o improve CPP signals. In this paper, the analytical solution for CPP signa ls is reported and an improved CPP method using signal processing is propos ed.