JP2006127698A - Optical disk recording/playing back device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To specify an absolute position in a medium by continuously generating prepit synchronous signals at constant intervals irrespective of the presence/absence of prepit detection when an optical disk recording/playing back device executes further recording from the recorded area of an optical disk. <P>SOLUTION: When recording is further started from a suspended position having data recorded in an optical disk, a prepit detection means synchronizes a data synchronous signal detected by a data synchronization detection means with the timing of generating a prepit synchronous signal to generate a sure prepit synchronous signal, and a recording control means counts writing clocks by a predetermined number of times based on the sure prepit synchronous signal to start recording. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical disk recording / reproducing apparatus for recording data on an optical disk and reproducing data from the optical disk.

  The optical disc recording / reproducing apparatus repeats the operations of writing and stopping data and further writing (adding) data to the optical disc. The optical disk here is a CD-R / RW, a DVD-R / RW, a DVD + R / RW, or the like.

  First, an outline of the start operation in the case where additional data is added after the data has been once written on the optical disk, particularly the DVD disk will be described. When new data is recorded on the DVD disk from the end of the recorded data, the sync code is first detected by the DVD decoder from the reproduction data read from the recorded part on the DVD disk. A data sync signal is generated at the timing when the sync code is detected. The recording control circuit generates new write data recording timing based on the data sync signal.

  The end point of the recorded data is the time when a predetermined number of write clocks has passed since the last data sync signal of the recorded data. The predetermined number of write clocks is set by the CPU. When the end position of the already recorded data is reached, additional recording is started.

  However, the above-described additional recording method only matches the end position of the recorded data, and may not be consistent with the media (optical disk) position. In addition, when the additional writing is repeated many times, the deviation from the media position is accumulated.

  Therefore, in the optical disc apparatus disclosed in Patent Document 1, when a deviation occurs between the data sync signal and the prepit on the medium (optical disc), the prepit sync signal generated by the LPP decoder, By controlling the frequency to increase / decrease, the deviation between the data to be added and the media position is corrected.

By the way, in order to generate the pre-pit sync signal, the pre-pits on the medium (optical disk) must be properly detected via the pickup and the signal detection amplifier. However, when trying to read a prepit in an already recorded area, position information may not be obtained accurately due to interference between a prepit signal and a recording mark. If the pre-pit signal and further the pre-pit sync signal are not detected, there will be no signal serving as a reference for correcting the deviation between the recording data and the medium. That is, when it is difficult to detect the prepits, it becomes impossible to match the position of the recording data with the position on the medium (optical disk).
Japanese Patent Laid-Open No. 2003-30841

  In the optical disc recording / reproducing apparatus, when data is written on an optical disc and further recorded, a probable pre-pit sync signal is generated on the basis of the data sync signal in the recorded portion, and whether or not the pre-pit is detected. The object is to specify the absolute position on the medium by continuously generating the pre-pit sync signal at regular intervals.

The present invention has been made to achieve the above object. An optical disc recording / reproducing apparatus according to claim 1 of the present invention provides:
Prepit detecting means for detecting a prepit of an optical disc and generating a prepit sync signal according to the detected prepit;
Reproduction clock generation means for reproducing data recorded on the optical disc and generating a reproduction clock from the reproduction signal;
Data sync detection means for detecting a predetermined sync signal included in the playback data in synchronization with the playback clock, and generating a data sync signal according to the detected sync signal;
Wobble information detecting means for detecting wobble information previously formed on the optical disc;
Write clock generation means for generating a write clock according to the write speed in synchronization with the wobble information;
Write data sync signal generation means for generating a write sync signal used for determining the timing of data writing in synchronization with the write clock;
An optical disc recording / reproducing apparatus comprising recording control means for recording data on an optical disc in synchronization with a write clock based on a write data sync signal. In the optical disc recording / reproducing apparatus,
The data sync signal detected by the data sync detection means when recording is further started from the interruption position where the data is recorded on the optical disc is synchronized with the timing at which the prepit detection means generates the prepit sync signal. Generate a pit sync signal,
The recording control means controls the write clock frequency so that the write data sync signal matches the probable pre-pit sync signal, and then starts recording by counting a predetermined number of write clocks based on the probable pre-pit sync signal. It is characterized by doing.

An optical disk recording / reproducing apparatus according to claim 2 of the present invention provides:
2. The optical disc according to claim 1, wherein the probable pre-pit sync signal is generated on the basis of a data sync signal of data at a predetermined address before an interruption position where data is recorded on the optical disc. A recording / reproducing apparatus.

An optical disk recording / reproducing apparatus according to claim 3 of the present invention is
A processor unit;
The processor unit delays the data sync signal detected by the data sync detection means by a predetermined time set in the processor unit,
2. The optical disc recording / reproducing apparatus according to claim 1, wherein the pre-pit detecting means uses the delayed data sync signal as a reference signal of a probable pre-pit sync signal.

An optical disk recording / reproducing apparatus according to claim 4 of the present invention provides:
2. The optical disc recording / reproducing apparatus according to claim 1, wherein the prepit detecting means continues generating the prepit sync signal at regular intervals based on the probable prepit sync signal after generating the probable prepit sync signal. It is.

  By using the present invention, when a discrepancy between a prepit sync signal and a write sync signal is generated, the increase / decrease in the frequency of the write clock is controlled with respect to the discrepancy. The deviation from the absolute position can be avoided.

  Hereinafter, preferred embodiments according to the present invention will be described with reference to the drawings.

First embodiment.
FIG. 1 is a block diagram of an optical disc recording / reproducing apparatus according to the first embodiment of the present invention. In the description of the embodiment, “DVD-R / RW” is assumed as the optical disk, but the present invention is applicable to a recording / reproducing apparatus for other optical disk media (for example, CD-R / RW and DVD + R / RW). Of course it is available.

  In FIG. 1, an optical disk recording / reproducing apparatus includes a spindle motor 4 that rotates and drives an optical disk (DVD-R / RW media) 2, a motor driver 6 and servo circuit 8 that perform rotation control, and an optical disk 2 that stores data. A pickup 14 for reading and writing, a read amplifier 16 for amplifying and binarizing a reproduction signal read by the pickup 14, a read clock generating circuit 12 for generating a read clock from the amplified reproduction signal, and synchronizing with the read clock A DVD decoder 18 that detects a sync signal from the input data and generates a data sync detection signal, an LPP (land pre-pit) decoder 28 that decodes a physical address and a sync signal on the disc from prepits on the optical disc 2, Control absolute position of physical address A recording control circuit 32 and a laser drive control circuit 24 that generate write start / stop timing from information obtained from the VD encoder 34 and the LPP decoder 28, and a write clock generation circuit 26 that generates a write clock from wobble on the medium. I have.

  Further, the optical disk recording / reproducing apparatus includes a buffer RAM 22 for temporarily storing data for processing recording / reproducing data, a circuit for processing data for recording / reproducing, a buffer manager 20 for arbitrating the buffer RAM 22, and a host. A host interface 10 that performs interface processing with a computer and a CPU (not shown) for controlling operations and making various settings for each circuit are provided.

  An operation of reading data from the optical disc 2 in the optical disc recording / reproducing apparatus will be described.

  First, the reproduction signal obtained by the pickup 14 is amplified and binarized by the signal detection amplifier 16 and then input to the read clock generation circuit 12 and the DVD decoder 18.

  The read clock generation circuit 12 generates a read clock based on the input reproduction signal and outputs it to the DVD decoder 18. The DVD decoder 18 detects a sync signal from the input data in synchronization with the read clock and generates a data sync detection signal. In addition, the DVD decoder 18 performs 8-16 demodulation on the input data, stores the data in the buffer RAM 22 as needed via the buffer manager 20, and stores the stored data in order to increase the reliability of the data. Error correction processing is performed on Data for which the error correction processing has been completed by the DVD decoder 18 is read via the buffer manager 20 by the host interface and transferred to the host computer 40.

  Next, the operation when data is written on the optical disc in the optical disc recording / reproducing apparatus will be described.

  First, the pickup 14 reads a pre-pit on the optical disc 2. Based on the reading of the prepit, the LPP decoder 28 generates a prepit sync signal and demodulates the address of the optical disc. Here, the pre-pits on the optical disc are called land pre-pits (LPP: Land Pre-Pit), which are formed in advance when the medium is manufactured. In the prepit, a pit pattern is formed according to a predetermined standard by a convex region called a land between concave grooves along the rotation direction of the optical disc.

  FIG. 2 is a waveform diagram showing the regularity of LPP based on the relationship between wobble and LPP. One sync frame is composed of eight wobble cycles, but the LPP is located in the first three wobbles every two sync frames. If the LPP pattern of the first 3 wobbles in the sync frame is “1-1-1”, it indicates an even position sector sync, and if “1-1-0”, it is an odd position sector sync. "1-0-1" indicates that the prepit data is "1", and "1-0-0" indicates that the prepit data is "0". . In short, this pre-pit data indicates an address on the disc.

  Then, the write clock generation circuit 26 generates a write clock corresponding to the write speed from the wobble on the optical disc. The recording control circuit 32 generates a write start / stop timing from information obtained from the LPP decoder 28, and enables writing at an accurate position.

  The outline of the flow of recording data is as follows. In response to a write command (write command) from the host computer 40, the host computer 40 first transfers data to the buffer RAM 22 via the buffer manager 20. The DVD encoder 34 reads the data in the buffer RAM 22 via the buffer manager 20, adds an error correction code, EDC code, SYNC code, header information, ID information, etc., and writes it back to the buffer RAM 22. Further, the DVD encoder 34 reads out the prepared data from the buffer RAM 22 via the buffer manager 20, modulates it by 8-16, and outputs it. Data output from the DVD encoder 34 is recorded on the DVD (optical disk) 2 via the laser drive circuit 24 and the pickup 14.

  FIG. 3 is a waveform diagram showing the timing of each signal when data is written to the optical disc and interrupted and added later. Here, it is assumed that the pre-pit signal cannot be obtained through the pickup and the signal detection amplifier in the recorded area.

  Assume that the recorded data is recorded on the optical disc 2 and the recording is interrupted at that time, as shown in the top “recorded data of the optical disc” in FIG. Recorded data on the optical disk is read through the pickup 14 and the signal detection amplifier 16, and the reproduced data is input to the read clock generation circuit 12 and the DVD decoder 18. The read clock generation circuit 12 generates a read clock based on the input reproduction data and outputs it to the DVD decoder 18. The DVD decoder 18 detects a sync code included in the reproduction data input from the signal detection amplifier 16 in synchronization with the input read clock, and generates a data sync signal for each sector at the detected timing.

  On the other hand, the LPP decoder 28 has a function of reading the wobble and LPP on the optical disc via the pickup 14 and the signal detection amplifier 16 and generating a prepit sync signal at the timing when the LPP is detected. In the example of the signal 3, the prepit signal in the recorded part is not detected, and as a result, the prepit sync signal in the recorded area cannot be generated.

  Therefore, the LPP decoder 28 included in the optical disc recording / reproducing apparatus according to the first embodiment generates a probable pre-pit sync signal with reference to the data sync signal in the recorded part. Here, the “probable pre-pit sync signal” is a pseudo signal used in place of the pre-pit sync signal detected and generated from the LPP. In the optical disc recording / reproducing apparatus according to the first embodiment, the LPP This is a signal generated by the decoder 28.

  Specifically, when writing is interrupted first, the demodulation address “N” at the time of the interruption in the optical disc recording / reproducing apparatus is known. Therefore, an additional recording procedure (sequence) with this demodulation address N as the target position Will be started. Here, when the pre-pit sync signal cannot be detected, the demodulation address can be calculated from the ID information extracted from the recorded data. If the pre-pit sync signal can be detected, the demodulation address can be calculated from the detection result.

  When the target position N is determined, the operation proceeds to the seek operation. The seek operation is a process in which the position on the optical disc is specified by reproducing recorded data on the optical disc or detecting wobble / LPP formed on the optical disc.

  A seek operation specifies a sector (N-3) three sectors before the target position N, and here, a timing reference signal serving as a reference for generating a probable pre-pit sync signal is generated. At the timing when this timing reference signal is generated, the DVD decoder 18 detects the data sync signal Y, and the LPP decoder 28 generates a probable pre-pit sync signal based on the data sync signal Y.

  Next, the process from the detection of the data sync signal Y to the generation of a probable pre-pit sync signal will be described below.

  As will be described later, the “probable pre-pit sync signal” is generated by the LPP decoder 28, but the LPP decoder 28 operates based on the wobble detected by the signal detection amplifier 16 in the first place. Since each wobble has inherent jitter, in order for the LPP decoder 28 to reliably generate a probable pre-pit sync signal from the data sync signal generated by the DVD decoder 18, the data sync signal and the wobble jitter are It is preferable that they do not overlap. Therefore, in order to avoid overlapping with wobble jitter, it may be preferable to shift the data sync signal Y by a slight time to obtain the signal Y ′. This shift amount can be set in advance by the CPU. In FIG. 3, the signal Y is shifted to a signal Y ′. The shift amount from the signal Y to the signal Y ′ may be determined as an optimum value by evaluation at the time of system construction.

  Next, the shifted data sync signal Y ′ is synchronized with the wobble operating the LPP decoder 28, and at this time, a bit counter and a word counter are preset to generate a “probable pre-pit sync signal”. . The bit counter counts from 0h to Fh every wobble within 2 sync frames, and the word counter counts from 0h to Ch every 2 sync frames within 1 sector. When the bit counter is “Fh” and the word counter is “Ch”, it is possible to generate a “probable pre-pit sync signal” (A) for each sector, which is the generation interval of the pre-pit sync signal. The preset values of these counters can be set in advance by the CPU.

  In the above-described process of generating a “predetermined prepit sync signal”, (1) the relationship between the wobble pre-engraved on the optical disc 2 and the prepit signal is constant, and (2) the wobble signal has a certain range of jitter. (3) Further, since the write clock is generated by the write clock generator 26 in synchronization with the wobble, the disc is reproduced from the recorded data by the write clock. It can be said that the data sync signal has a fixed phase relationship with the original prepit sync signal generated from the prepits on the disc. Therefore, even if the pre-pit sync signal on the disc cannot be accurately reproduced, it can be said that the “probable pre-pit sync signal” can be estimated and reproduced from the data sync signal.

  Next, an operation for generating a “probable pre-pit sync signal” at intervals of one sector will be described.

  First, when a pre-pit can be detected via the pickup 14 and the signal detection amplifier 16, the state of the LPP decoder 28 changes as shown in FIG.

  First, a pattern (“1-1-1” or “1-1-0”) which is a pre-pit sector sync is searched in the search mode 50, and if detected, the process proceeds to the next check mode 52 and is not detected. In the case of, the search is continued in the search mode 50 until the sector sync pattern can be detected.

  In the check mode 52, after the sector sync detected in the search mode 50 is detected, the pre-pit data pattern (“1-0-1” or “1-0-0”) corresponds to the predicted position (for example, every two sync frames). When the degree is detected, the process proceeds to the next protect mode 54, and if the detection at the predicted position is insufficient, the sector sync 52 is detected again from the search mode 50.

  In the protect mode 54, the state (mode) is maintained if the sector sync pattern or the prepit data pattern of the prepit can be continuously detected at the predicted position, and the sector sync pattern or the prepit data pattern can be continuously detected at the predicted position. When no more, the search mode 50 is restored. Since the pre-pits are detected at regular intervals during the protect mode 54, a pre-pit sync signal is generated in this mode. In the protect mode 54, prepit sync signals are generated at regular intervals. At this time, the bit counter and the word counter described above are incremented with reference to the sector.

  Here, when the LPP decoder 28 generates the “probable pre-pit sync signal” shown in FIG. 3 on the basis of the data sync signal Y, the bit mode and the word counter are preset and the check mode 52 is forcibly set. To the protect mode 54. Further, the path is blocked so as not to return to the search mode after forcibly changing to the protect mode 54.

  As described above, a data sync signal is generated from the reproduction data signal in the recorded area, and the prepit generation timing reference is determined as (N-3), thereby generating a “probable prepit sync signal A”. Then, a pre-pit sync signal can be generated at equal intervals of B, C, D,.

  Next, the process from the generation of the pre-pit sync signal to the additional recording from the end of the recorded area will be described.

  After the generation of the pre-pit sync signal A, the pre-pit sync signal B confirms that it is two sectors before the target position (N-2). Further, based on the generation of the pre-pit sync signal C in the write-once preparation sector (N-1), after the recording control circuit 32 counts the number of write clocks set in advance by the CPU, the write start signal is written. The recording control circuit 32 outputs the gate signal. Here, the additional writing is started. The number of write clocks set by the CPU varies depending on the write speed and the like, and an appropriate value can be set. Here, the recording control circuit 32 controls the frequency of the write clock so that the write data sync signal matches the likely pre-pit sync signal.

  With the above operation, even if it is difficult to detect a prepit in an already recorded area on the optical disc, a probable prepit sync signal can be generated, so that the absolute position on the medium can be specified. As a result, even if a deviation between the pre-pit sync signal and the data sync signal occurs, the deviation between the recording data and the media position can be corrected by controlling the frequency of the write clock with respect to the deviation.

1 is a block diagram of a disc recording / reproducing apparatus according to a first embodiment of the present invention. It is a wave form diagram which shows the relationship between wobble and LPP. It is a wave form diagram which shows the relationship of the various signals relevant to the production | generation of a reliable prepit sync signal. It is a figure which shows the transition of the state of a LPP decoder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Optical disk, 12 ... Read clock generation circuit, 14 ... Pickup, 18 ... DVD decoder, 26 ... Write clock generation circuit, 28 ... LPP decoder, 30 ... Position shift Detection circuit, 32 ... recording control circuit, 34 ... DVD encoder.

Claims (4)

Prepit detecting means for detecting a prepit of an optical disc and generating a prepit sync signal according to the detected prepit;
Reproduction clock generation means for reproducing data recorded on the optical disc and generating a reproduction clock from the reproduction signal;
Data sync detection means for detecting a predetermined sync signal included in the playback data in synchronization with the playback clock, and generating a data sync signal according to the detected sync signal;
Wobble information detecting means for detecting wobble information previously formed on the optical disc;
Write clock generation means for generating a write clock according to the write speed in synchronization with the wobble information;
Write data sync signal generation means for generating a write sync signal used for determining the timing of data writing in synchronization with the write clock;
In an optical disc recording / reproducing apparatus comprising recording control means for recording data on an optical disc in synchronization with a write clock with reference to a write data sync signal,
The data sync signal detected by the data sync detection means when recording is further started from the interruption position where the data is recorded on the optical disc is synchronized with the timing at which the prepit detection means generates the prepit sync signal. Generate a pit sync signal,
The recording control means controls the write clock frequency so that the write data sync signal matches the probable pre-pit sync signal, and then starts recording by counting a predetermined number of write clocks based on the probable pre-pit sync signal. An optical disc recording / reproducing apparatus.   2. The optical disc according to claim 1, wherein the probable pre-pit sync signal is generated on the basis of a data sync signal of data at a predetermined address before an interruption position where data is recorded on the optical disc. Recording / playback device. A processor unit;
The processor unit delays the data sync signal detected by the data sync detection means by a predetermined time set in the processor unit,
2. The optical disc recording / reproducing apparatus according to claim 1, wherein the pre-pit detecting means uses the delayed data sync signal as a reference signal of a probable pre-pit sync signal. 2. The optical disc recording / reproducing apparatus according to claim 1, wherein the prepit detecting means continues generating the prepit sync signal at regular intervals based on the probable prepit sync signal after generating the probable prepit sync signal. .

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