Method and device for protecting a preamplifier in reading signals on a defect disc

A method for protecting a preamplifier in reading signals on a defect optical disc, said method comprising:

• receiving a plurality of defect detection signals to set a plurality of defect flag signals, wherein said plurality of defect detection signals comprise at least an envelope of RF signal and bit modulation signals;
• performing logic operation on said defect flag signals in order to detect a specified defect;
• and
• using corresponding boost gain and cut-off frequency to equalize and recover an RF signal affected by said specified defect, while a specified defect is detected.

A device for protecting a preamplifier in reading signals on a defect optical disc, said device comprising:

• a defect detection unit, receiving a plurality of defect detection signals to set a plurality of defect flag signals, wherein said plurality of defect detection signals comprise at least an envelope of a RF signal and bit modulation signals;
• and
• a logic combination unit, performing logic operation on said defect flag signals in order to detect a specified defect;
• wherein said logic combination unit controls said preamplifier to use a fixed gain or a previously preserved gain by said specified defect raising, so as to avoid a RF signal, affected by said specified defect, being charging up.