摘要:
When data is reproduced by an apparatus which is different from an apparatus used for recording the data, the fluctuation of edge positions of the reproducing data increases, making reproduction incompatible, and the present invention solves this problem. The present invention comprises reproducing learning means 13 and 24 for switching a frequency characteristic of the reproducing system, which detects the changes of the local optical constant, to a predetermined frequency characteristic, and recording learning means 20 for correcting the start edge or end edge position of the recording pulse for each combination of length of a mark block and length of the preceding or subsequent space, so that the edge position of the binarized reproducing data comes to a desired position, and since the frequency characteristic of the reproducing system is unified before learning the edge shift amount caused by the thermal interference between marks, the length of the recorded marks and spaces can always be constant, which improves the reproducing compatibility among reproducing apparatuses.
摘要:
A method for controlling intensities of a plurality of laser beams respectively emitted on a track of an optical disk by a plurality of laser diodes according to the present invention includes a step of performing focusing servo control for focusing one of the plurality of laser beams emitted by one of the plurality of laser diodes onto the track, and concurrently controlling an intensity of the laser beam emitted by each of plurality of laser diodes to be within a predetermined range by comparing a signal which is in accordance with an intensity of the laser beam emitted by that laser beam with a reference signal. A period during which the one of the plurality of laser diodes used for the focusing does not emit the one laser beam is shorter than a response time of the focus servo control.
摘要:
According to the present invention, an optical disk recording method for recording data on an optical disk including a land and a groove by forming a mark representing the data on the optical disk by irradiating a light beam onto the optical disk is provided. In this method, conditions for irradiating the light beam are varied depending upon whether a position at which the mark representing the data is formed on the land or on the groove so that a size of the mark formed on the land is equal to a size of the mark formed on the groove.
摘要:
An analog-to-digital converter executes analog-to-digital conversion of a first analog video signal at a predetermined sampling frequency "fs". A time base converter converts a time base of an output signal from the analog-to-digital converter at a predetermined time base conversion frequency "ftci". A digital output signal from the time base converter is converted into a corresponding second analog video signal in response to a clock signal of a frequency corresponding to the frequency "ftci". The second analog video signal is converted into an FM video signal recorded on a video region of an optical disk. A binary audio digital signal is converted into a multi-level form digital audio signal. The binary audio digital signal has a data rate corresponding to the frequency "ftci". The multi-level form digital audio signal has a data rate "ftci/n" and 2.sup.n discrete amplitude levels where "n" denotes a predetermined integer. The multi-level form digital audio signal is converted into a corresponding analog audio signal in response to the clock signal of the frequency corresponding to the frequency "ftci". The analog audio signal is converted into an FM audio signal recorded on an audio region of the optical disk. A data signal generator generates a digital data signal at a data rate "ftci/m" where "m" denotes a predetermined integer. The digital data signal is converted into a corresponding analog data signal in response to the clock signal of the frequency corresponding to the frequency "ftci". The analog data signal is converted into an FM data signal recorded on a data region of the optical disk.
摘要:
An information recording apparatus for continuously recording information without losing any information even if the apparatus temporarily falls into a recording-disable state owing to the shock externally applied, etc. is provided. A disability detector for detecting the recording-disable state is provided in the information recording apparatus, thereby interrupting the recording operation and the reading operation from the buffer memory under the recording-disable state, and making a coding rate reduction controller instruct a coder to temporarily reduce the coding rate of the input information. A remaining capacity detector is provided for monitoring the remaining capacity in the buffer memory and instructing the coder to temporarily reduce the coding rate of the input information when the remaining capacity becomes a predetermined value or less. As a result, the reduction in the remaining capacity of the buffer memory under the recording-disable state is prevented. When the overflow of the buffer memory is detected, the information after the generation of the overflow is controlled to be overwritten on a part of the data already written into the buffer memory. The variation history of the case where the recording data amount is varied by the coder because of the variation in the coding rate of the input information or the overwriting operation in the buffer memory is controlled to be recorded on the disk as rate variation management information. By dividing the recording area on a disk-shaped information recording medium into an inner circumference and an outer circumference and recording on the outer circumference after the return from the recording-disable state, the recording transfer rate after the return becomes higher.
摘要:
A digital information playback apparatus comprises A/D converter that converts a playback signal into digital data, a maximum likelihood decoder that decodes the quantized data output from the A/D converter to obtain the original digital information, and a timing signal extractor that generates a sampling clock used in the A/D converter, and wherein the maximum likelihood decoder detects the response characteristic of the record/playback system and obtains level fluctuations contained in the playback signal, based on the survival path obtained as a maximum likelihood decoding result, to control the expected multilevel equalized values used in the maximum likelihood decoder, the timing signal extractor obtains level fluctuations, based on the survival path obtained as a maximum likelihood decoding result, and obtains the component of the level fluctuations due to phase shifts of the sampling clock of the VCO to control the phase of the sampling clock of the VCO.
摘要:
The optical data recording method comprising the steps of: modulating data to be recorded, to generate a plurality of recording modulation codes; and emitting a pulse-like light beam to an optical disc, so that a plurality of recording marks and spaces which have lengths corresponding to the plurality of recording modulation codes are formed on the optical disc. In the optical data recording method, at least two of the plurality of recording marks comprises: a first pulse which is disposed at a front and forms a leading edge of the recording mark, a last pulse which is disposed at a backend and forms a trailing edge of the recording mark, and a multi-pulse train which is disposed between the first pulse and the last pulse and forms a center of the recording mark. The multi-pulse train has a pulse period longer than T which represents a reference period of the recording modulation code.
摘要:
The optical data recording method comprising the steps of: modulating data to be recorded, to generate a plurality of recording modulation codes; and emitting a pulse-like light beam to an optical disc, so that a plurality of recording marks and spaces which have lengths corresponding to the plurality of recording modulation codes are formed on the optical disc. In the optical data recording method, at least two of the plurality of recording marks comprises: a first pulse which is disposed at a front and forms a leading edge of the recording mark, a last pulse which is disposed at a backend and forms a trailing edge of the recording mark, and a multi-pulse train which is disposed between the first pulse and the last pulse and forms a center of the recording mark. The multi-pulse train has a pulse period longer than T which represents a reference period of the recording modulation code.
摘要:
An optical disk is provided which includes a rewritable first recording area and a read-only second recording area. The first recording area includes groove tracks and land tracks divided into first sectors. Each first sector has a header region with identification data and a data region for recording user data. The second recording area includes tracks formed with physical bit rows, the tracks being divided into second sectors. Each second sector includes a header region and a data region having read-only data recorded as the bit rows. The header regions in the first sectors include pits the width of groove tracks and wobbled from a center line of the groove track. The header regions in the second sectors include pits having a width smaller than the groove tracks and formed along the center line of a track.
摘要:
The optical data recording method comprising the steps of: modulating data to be recorded, to generate a plurality of recording modulation codes; and emitting a pulse-like light beam to an optical disc, so that a plurality of recording marks and spaces which have lengths corresponding to the plurality of recording modulation codes are formed on the optical disc. In the optical data recording method, at least two of the plurality of recording marks comprises: a first pulse which is disposed at a front and forms a leading edge of the recording mark, a last pulse which is disposed at a backend and forms a trailing edge of the recording mark, and a multi-pulse train which is disposed between the first pulse and the last pulse and forms a center of the recording mark. The multi-pulse train has a pulse period longer than T which represents a reference period of the recording modulation code.