Patent ID: 7460449

Claim:
A method for reading preinstalled information in a recordable optical recording medium for reading the preinstalled information from the recordable optical recording medium that contains preinstalled information, the recordable optical recording medium containing a substrate engraved with a spiral pregroove for providing a tracking servo signal, the track of the pregroove being a slightly wobbled spiral curve, the method comprising the steps of: extracting a wobble signal from the tracking servo signal, removing signals in non-wobble bands with the wobble containing a plurality of first waveforms, second waveforms, and third waveforms with same fundamental cycles, the duty cycles of the first waveform, the second waveform and the third waveform being all distinct, with that of the first waveform being 1; outputting a clock generating signal according to the wobble signal; making a 90-degree phase shift on the clock generating signal to produce a phase corrected signal; integrating the wobble signal and performing resets according to the rising and lowering edges of the phase corrected signal to output an integrated and reset wobble signal; and cutting the integrated and reset wobble signal into a preinstalled information signal.