Patent ID: 7339867

Claim:
A defect-signal generating circuit comprising: a peak-hold signal generating circuit for generating a peak-hold signal by holding the peak of an RF signal read out from a recording medium; an intermediate-signal generating circuit, which is a peak-holding circuit having a longer time constant than said peak-hold signal generating circuit, for generating an intermediate signal by holding the peak of said RE signal; a signal-level adjusting circuit for generating a threshold signal by shifting the signal level of said intermediate signal; a threshold-signal adjusting circuit for adjusting the signal level of said threshold signal; and a comparator for generating a defect signal by comparing said peak-hold signal with said threshold signal; wherein said threshold-signal adjusting circuit includes at least one of a first adjusting circuit for adjusting the signal level of said threshold signal in the event that the signal level of said peak-hold signal falls below that of said threshold signal, due to the signal level of said peak-hold signal and that of said threshold signal being reversed, so as to raise the signal level of said threshold signal higher than that in the case of no adjustment being performed, and a second adjusting circuit for adjusting the signal level of said threshold signal in the event that the signal level of said peak-hold signal rises above that of said threshold signal, due to the signal level of said peak-hold signal and that of said threshold signal being reversed, so as to lower the signal level of said threshold signal lower than that in the case of no adjustment being performed.