Equalizer for optical recording/reproducing apparatus and equalizing method thereof

An equalizing method of an optical recording/reproducing apparatus comprising:

• a step of removing pre-cursor from inter-symbol interference of input signal by a feedforward (FF) filter and outputting a FF output signal;
• a step of predicting post-cursor of the inter-symbol interference and outputting a result of prediction by a feedback (FB) filter in a FB output signal;
• a step of first adding the FF output signal having the pre-cursor removed and the FB output signal having the predicted post-cursor, to remove the inter-symbol interference and outputting a first output signal;
• a step of second adding the FF output signal having the pre-cursor removed and the FB output signal having the predicted post-cursor, to remove the inter-symbol interference and outputting a second output signal;
• a step of deciding a level of the first output signal from the first adding step to be a predetermined level and feeding back a predetermined level signal to the feedback filter;
• and
• a step of detecting the second output signal outputted from the second adding step as a predetermined signal, using at least one of a trellis structure method and a tree structure method.

An equalizer of optical recording/reproducing apparatus comprising:

• a feedforward (FF) unit having a feedforward filter for removing pre-cursor from inter-symbol interference of input signal and outputting a FF output signal;
• a feedback (FB) unit having a feedback filter for predicting post-cursor of the inter-symbol interference and outputting a result of prediction in a FB output signal;
• a first adder and a second adder, each for adding the output signal from the FF unit and the output signal from the FB unit, to remove the inter-symbol interference;
• and respectively outputting a first output signal and a second output signal;
• and
• a signal detection unit for detecting the second output signal from the second adder as a predetermined signal using at least one of a trellis structure method and a tree structure method, and feeding back the predetermined signal to the FB unit,
• wherein the FB unit predicts the post-cursor based on the predetermined signal that is feedback from the signal detection unit after a certain period of time.

An equalizing method of optical recording/reproducing apparatus comprising:

• a step of removing pre-cursor from inter-symbol interference of input signal by a feedforward filter and outputting a FF output signal;
• a step of predicting post-cursor of the inter-symbol interference and outputting the result of prediction by a feedback filter in a FB output signal;
• a step of first adding the FF output signal having the pre-cursor removed and the FB output signal having the post-cursor predicted, to remove the inter-symbol interference, and outputting a first output signal;
• a step of second adding the FF output signal having the pre-cursor removed and the FB output signal having the post-cursor predicted, to remove the inter-symbol interference, and outputting a second output signal;
• and
• a step of detecting the second output signal outputted from the second adding step as a predetermined signal, using at least one of a trellis structure method and a tree structure method and feeding back the detected predetermined signal to the feedback filter,
• wherein the step of detecting the second output signal outputted from the second adding step further inputting the detected predetermined signal to the feedback filter after a certain period of time.