| US 7,403,460 B2 | ||
| Information recording and reproducing apparatus, evaluation method, and information recording and reproducing medium | ||
| Yuji Nagai, Kawasaki (Japan); Yutaka Kashihara, Chigasaki (Japan); and Akihiro Ogawa, Yokohama (Japan) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan) | ||
| Filed on Aug. 10, 2006, as Appl. No. 11/501,705. | ||
| Application 11/501705 is a continuation of application No. 10/387134, filed on Mar. 13, 2003, granted, now 7,139,231. | ||
| Claims priority of application No. 2002-069138 (JP), filed on Mar. 13, 2002. | ||
| Prior Publication US 2006/0280093 A1, Dec. 14, 2006 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. G11B 20/10 (2006.01) | ||
| U.S. Cl. 369—59.22 [369/124.07] | 5 Claims |
| 1. An information reproducing apparatus for detecting data recorded in a medium by Partial Response and Maximum Likelihood
signal processing units and an equalizer, the apparatus comprising:
a table which stores plural pairs of a true pattern and a false pattern;
a pattern comparator which compares the detected data with the true patterns and the false patterns stored in the table to
find a pair of the true pattern and the false pattern one of which pattern coincides with the detected data; and
a calculating device which, when the pattern comparator finds the pair, calculates:
a first Euclidean distance E2F,S between an output signal of the equalizer and an ideal signal of the false pattern included in the detected pair,
a second Euclidean distance E2T,S between an output signal of the equalizer and an ideal signal of the true pattern included in the detected pair,
a difference between the first Euclidean distance and the second Euclidean distance, and
an average (μ) and a standard deviation (σ) of a distribution of the difference, wherein the detected data is evaluated based
on
 where F(0) denotes a probability of occurrence by mistaken identification from a true pattern to a false pattern.
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