TLN signal generating apparatus used in optical disc drive and optical disc drive equipped with the apparatus, and optical disc drive equipped with amplitude adjusting apparatus for tracking error signal

A TLN signal generating apparatus used in an optical disc drive, which comprises:

• TLN signal generating means for generating a TLN signal (track loss signal) based on signals obtained from an optical pick-up;
• offset component detecting means for detecting an offset component (direct current component) contained in the TLN signal generated by the TLN signal generating means;
• signal control means for controlling, responsive to a level of the offset component detected by the offset component detecting means, a level of the TLN signal generated by the TLN signal generating means so that the offset component in the TLN signal is reduced or eliminated therefrom;
• and
• a digitizing circuit for digitizing the TLN signal which has been corrected by the signal control means by comparing it with a reference level.

A TLN signal generating apparatus used in an optical disc drive, which comprises:

• TLN signal generating means for generating a TLN signal (track loss signal) based on signals obtained from an optical pick-up;
• a signal correcting circuit which amplifies an alternating current component contained in the TLN signal generated by the TLN signal generating means without eliminating a directed current component contained in the TLN signal;
• and
• a digitizing circuit for digitizing the TLN signal which has been corrected by the signal correcting circuit by comparing it with a reference level.

An optical disc drive having an amplitude adjusting apparatus for a tracking error signal, the amplitude adjusting apparatus comprising:

• amplifying means for amplifying a tracking error signal generated based on a signal obtained from an optical pick-up with a variable amplification factor;
• amplification value detecting means for detecting an amplification value of the tracking error signal from the amplifying means;
• and
• means for variably controlling the amplification factor of the amplifying means so that the amplification value detected by the amplification value detecting means becomes substantially coincide with a reference amplification value which is used as a reference level of the tracking error signal by comparing the amplification value detected by the amplification value detecting means with the reference level of the tracking error signal.