Patent ID: 6982941

Claim:
A mirror detection signal generator, which generates a mirror detection signal from an RF signal corresponding the reflected light from a recording medium, comprises the following parts: a first peak-hold circuit that holds the bottom level of said RF signal and having a first droop rate and outputs a bottom-hold signal; a second peak-hold circuit that holds the top level of said RF signal and having a second droop rate and outputs a first envelope signal; a third peak-hold circuit that holds the bottom level of said RF signal and having a third droop rate and outputs a second envelope signal; a first reference signal generator that outputs the first reference signal generated on the basis of said bottom-hold signal and said first envelope signal; a first comparator that compares said first reference signal with said second envelope signal and generates said mirror detection signal; a fourth peak-hold circuit that holds the top level of said RF signal and having a fourth droop rate and outputs a top-hold signal; a second reference signal generator that outputs the second reference signal generated on the basis of said top-hold signal and said bottom-hold signal; and a second comparator that compares said second reference signal and said first envelope signal and generates a defect detection signal, said first droop rate being controlled by said defect detection signal.