Method and apparatus for generating absolute time in pregroove data

Abstract

An apparatus and a method for generating an ATIP data are provided. The apparatus, based on a wobble signal generated by reading a re-writable compact disc, generates an ATIP data; the apparatus includes: a frequency demodulator for demodulating the wobble signal to generate an original ATIP data signal; an ATIP clock generating circuit for generating an ATIP clock signal based on the wobble signal; and a data generating circuit, coupled to the frequency demodulator and the ATIP clock generating circuit, for generating the ATIP data based on the number of the original ATIP data signal at a first logic level during one period of the ATIP clock signal. This apparatus uses the number of the original ATIP data signal at a first logic level during one period of the ATIP clock signal and the bi-phase rule to precisely generate the ATIP data.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the priority benefit of Taiwan application Ser. No. 93108817, filed on Mar. 31, 2005. All disclosure of the Taiwan application is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention generally relates to a method of generating absolute time in pregroove (ATIP) data, and more particularly to a method of generating ATIP data based on an original ATIP data signal generated by a wobble signal and an ATIP clock signal. [0004] 2. Description of Related Art [0005] During the manufacture of the re-writable compact disk (CD), a shallow groove will be made from the center of the CD toward the outer circumference in spiral way. This groove is so-called pregroove. This pregroove is not a perfect spiral but a little wobbling. Generally, in a CD made by die-casting, each sector includes the timing-related data to control the spin speed of the CD-ROM drive in order ...

AI Technical Summary

Benefits of technology

[0015] In an embodiment of the present invention, the step of generating the ATIP data signal by using one predetermined threshold further includes: comparing the number of the ATIPORG signal at the first logic level with a predetermined threshold; asserting the ATIP data to the first logic level when the number of the ATIPORG signal at the first logic level is larger than or equal to the predetermined threshold; and de-asserting the ATIP data to a second logic level when the number of the ATIPORG signal at the first logic level is smaller than the predetermined threshold.

[0016] In an embodiment of the present invention, the step of generating the ATIP data signal by using two predetermined threshold further includes: adding all PRDDIFF data within the period of the ATIPCLK signal to obtain the adding data; comparing the number

Problems solved by technology

Therefore, how to effectively read the wobble signal from the CD-RW and to effectively

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