Patent ID: 7046591

Claim:
An apparatus for detecting the number of the tracks traversed on an optical disk, comprising: a differentiation part for differentiating a data signal outputted from a bandpass filter, said differentiation part being provided on a stage next to the bandpass filter for eliminating a low DC component, a high frequency component and noise of an input data signal; a sample trigger generating circuit for generating top and bottom signals in response to a data signal outputted through the differentiation part and a signal outputted through first and second comparators; a top hold part and a bottom hold part for holding the data signal at top and bottom; a subtraction part for performing a subtraction to obtain a signal difference between the top hold signal and the bottom hold signal outputted from the top and bottom hold parts; and a third comparator for performing a binarization of the signal difference value of the top and bottom hold parts outputted from the subtraction part.