Abstract: An inspection apparatus for inspecting a phase modulated wobble track of an optical disk is provided. A radial push-pull signal (a wobble signal) of an optical disk is supplied to a low pass filter where a phase boundary portion of the wobble signal is smoothed, and then binarized by a binarizer and supplied to a time interval analyzer. The time interval analyzer analyzes a period of the binary wobble signal to extract two peak values T1 and T2 thereof. An operation device computes a difference value of the two periods T1 and T2 and a standard deviation of each peak, and compares each computed value to a threshold value for simultaneously evaluating CNR and a phase shift. The low pass filter and the binarizer may be incorporated into an optical disk apparatus for smoothing the phase boundary portion of the reproduced wobble signal.

Abstract: A high-definition optical disk device for recording and reproducing data with respect to lands and grooves of an optical disk. The grooves and the lands of the optical disk are wobbled, and address information is embedded in gray code. In the grooves and the lands, both groove track address systems and land track address systems are embedded and form redundant systems. When detecting the address of a land, in addition to demodulation of the address data from the land track address system, the address data is also extracted from the groove track address system. The address data thus extracted is used for verification to detect an error in the demodulated address data.