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 |
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.
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