Patent ID: 6101227
Filing Date: 2000-08-08
Classification: G11B,H04L

Abstract:
A detector for providing a transition signal to indicate a defect comprising:a metric circuit operable to receive a discrete, equalized signal and to generate the transition signal in response, the metric circuit operable to provide the transition signal to indicate the defect as an output of the detector;a trellis circuit operable to receive the transition signal to indicate the defect and to perform sequence decoding, the trellis circuit operable to provide a digital data output signal in response;wherein the metric circuit comprisesa first adder circuit operable to add a positive threshold value to the discrete, equalized signal and to generate a first sum in response;a second adder circuit operable to add a negative threshold value to the discrete, equalized signal and to generate a second sum in response;a first comparator operable to compare the first sum and a current metric value and to generate a positive transition signal in response;a second comparator operable to compare the second sum and the current metric value and to generate a negative transition signal in response; anda sample/hold circuit operable to receive the positive transition signal and the negative transition signal and to provide the current metric value, the sample/hold circuit operable to update the current metric value with the first sum if the positive transition signal indicates that the first sum is less than the current metric value and to update the current metric value with the second sum if the negative transition signal indicates that the second sum is greater than the current metric value.