Optical disc discriminating system
AssigneePioneer Electronic Corporation
InventorsKazuo Kuroda, Shoji Taniguchi
Life of this patent
Estimating the term…
Abstract
An optical disc discriminating system comprises: a tracking error signal generating means adapted to generate a tracking error signal whose amplitude level varies with a groove depth of information tracks on an optical disc; a tracking servo means for directing a laser beam along an information track on the optical disc in accordance with the tracking error signal; a comparator adapted to compare the amplitude level of the tracking error signal supplied from the tracking error signal generating means with a reference level, with a tracking servo loop of the tracking servo means in an opened condition; a discriminating means adapted to discriminate the first and second groups of optical discs in accordance with a result from the comparator.
Claims8
An optical disc discriminating system adapted to discriminate from other optical discs a specific optical disc which has information tracks wobbled with a wobble signal having a predetermined frequency and a head portion formed on a front portion of each recording sector, said discriminating system comprising:
- a tracking error signal generating means for generating a tracking error signal;
- a tracking servo means for directing a laser beam along an information track on the optical disc in accordance with the tracking error signal;
- an extractor for extracting the wobble signal;
- a comparator for comparing the wobble signal with a reference value;
- a first pulse generator for producing a first pulse signal which has a longer time period than that of the wobble signal period, in synchronism with a output of the comparator;
- a second pulse generator for producing a second pulse signal which has a longer time period than that of one recording sector period, in synchronism with the first pulse signal;
- and
- a discriminating means adapted to discriminate the specific optical disc from the other optical discs, in accordance with the first and second pulse signals when a tracking servo loop of the tracking servo means is in a closed condition.
An optical disc discriminating system adapted to discriminate from other optical discs a specific optical disc which has information tracks wobbled with a wobble signal having a predetermined frequency and prepits formed between adjacent tracks, said discriminating system comprising:
- a tracking error signal generating means for generating a tracking error signal;
- a tracking servo means for directing a laser beam along an information track on the optical disc in accordance with the tracking error signal;
- a prepit detector for detecting the prepits;
- a decoder for demodulating a prepit detection signal outputted from the prepit detector and for extracting pre-information from the prepit detection signal or an error;
- and
- a discriminating means adapted to discriminate the specific optical disc, in accordance with output signals fed from the prepit detector and the prepit decoder when a tracking servo loop of the tracking servo means is in a closed condition.
An optical disc discriminating method adapted to discriminate from other optical discs a specific optical disc which has information tracks wobbled with a wobble signal having a predetermined frequency and a head portion formed on a front portion of each recording sector, said discriminating method comprising the steps of:
- generating a tracking error signal;
- directing a laser beam along an information track on the optical disc in accordance with the tracking error signal;
- extracting the wobble signal;
- comparing the wobble signal with a reference value;
- producing a first pulse signal which has a longer time period than that of the wobble signal period, in accordance with a result of the comparing;
- producing a second pulse signal which has a longer time period than that of one recording sector period, in accordance with the first pulse signal;
- and
- discriminating the specific optical disc, in accordance with the first and second pulse signals.
An optical disc discriminating method adapted to discriminate from other optical discs a specific optical disc which has information tracks wobbled with a wobble signal having a predetermined frequency and prepits formed between adjacent tracks, said discriminating method comprising the steps of:
- generating a tracking error signal;
- directing a laser beam along an information track on the optical disc in accordance with the tracking error signal;
- detecting the prepits;
- demodulating a prepit detection signal outputted from the prepit detector and extracting pre-information or an error;
- and
- discriminating the specific optical disc, in accordance with a result of the detecting and demodulating.
Dependencies are inferred from the claim text.