US 6,982,941 B2
Mirror detection signal generator
Koyu Yamanoi, Funabashi (Japan); Hironobu Murata, Yokohama (Japan); and Toshio Yamauchi, Yokohama (Japan)
Assigned to Texas Instruments Incorporated, Dallas, Tex. (US)
Filed on Feb. 08, 2002, as Appl. No. 10/72,100.
Claims priority of application No. 2001-059294 (JP), filed on Mar. 02, 2001.
Prior Publication US 2003/0152000 A1, Aug. 14, 2003
Int. Cl. G11B 7/09 (2006.01)
U.S. Cl. 369—53.22 12 Claims
OG exemplary drawing
 
1. 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.