Patent ID: 8238208
Filing Date: 2012-08-07
Classification: G11B

Abstract:
1. A defect-detecting circuit for detecting a defect area on a disc track, the defect-detecting circuit comprising: a first bottom hold unit, for receiving a source signal and holding the bottom level of the source signal, thereby outputting a first signal at a first rise rate; a first adder, for adding a first threshold value and the first signal, thereby generating a first slice signal; a second bottom hold unit, for receiving the source signal and holding the bottom level of the source signal, thereby outputting a second signal at a second rise rate; a second adder, for adding a second threshold value and the second signal, thereby generating a second slice signal; a multiplexer, having a first input end to receive the first slice signal, a second input end to receive the second slice signal, an output end and a select end; and a comparator, having a first end receiving the source signal and a second end coupled to the output end of the multiplexer, for comparing the source signal with either the first slice signal or the second slice signal, thereby generating a defect signal, wherein the first slice signal and the second slice signal are selectively outputted from the multiplexer according to the defect signal inputted into the select end of the multiplexer.