The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 19, 2005
Filed:
Jun. 04, 2002
Chih-yuan Chen, Chang-Hua Hsien, TW;
Chih-Yuan Chen, Chang-Hua Hsien, TW;
Media Tek Inc., Hsin-Chu, TW;
Abstract
A defect detection method is used to generate a disc defect signal while recording or reproducing information recorded onto an optical disc. The method compares the difference between a reflected light intensity signal (SBAD) and a low-pass filtered SBAD with a predetermined level. A defect signal is generated during a period when the difference exceeds a predetermined value. The defect signal opens a switch to hold the low-passed signal of the SBAD and disconnects the low-pass filter from the SBAD at the moment a defect signal occurs. The held value of the low-passed signal effectively replaces the low-passed signal until the difference between the SBAD and held low-passed signal returns to within the predetermined limits, which re-closes the switch re-connecting the low-pass filter to the SBAD.