JP2008010069A - Optical disk drive and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk drive which can detect a sink pattern of a wobble signal with high reliability. <P>SOLUTION: The optical disk drive is characterized by comprising a phase detection section which carries out phase detection of the wobble signal and generates wobble data; a sync detection section which detects a sink signal using the sink pattern as a standard; a first protection window generation section which generates a first protection window from a position of the detected sink signal and a first cycle specified as a cycle of the sink signal; a second protection window generation section which generates a second protection window which repeats at a position where the sink signal should appear with a second cycle from the wobble data; a sink signal decision section which decides the sink signal when the sink signal is in the first and second protection windows; and an address extraction section which extracts physical address information included in the wobble data by synchronizing it with the decided sink signal. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus and a control method thereof, and more particularly to a recording / reproducing optical disc apparatus and a control method thereof.

  In the recording / reproducing optical disc apparatus, a “wobble address recording method” is used. The “wobble address recording method” is a method of reading out physical address information embedded in a track of a recording / reproducing optical disc and determining a recording / reproducing position.

  In this method, a “wavy groove”, that is, “wobble” is provided in a track of an optical disc, and a wobble synchronization signal (hereinafter referred to as a sync) and a physical address (hereinafter referred to as an address modulation code) are modulated by modulating the wavy waveform. In some cases).

  A physical address can be obtained by reading and demodulating these patterns embedded in a specific position of a recording / reproducing optical disc.

  Specifically, for example, as described in Patent Document 1, a laser beam is irradiated onto an optical disc, and a wobble signal is generated from a reflected wave whose amplitude varies according to the wobble waveform. The wobble waveform is normally phase-modulated, and the phase of “0 degree” or “180 degree” is associated with “1” or “0” data of the sync or address modulation code. . Therefore, the wobble signal generated from the reflected wave of the optical disc is also a signal that is phase-modulated by the sync or the address modulation code.

The wobble signal is phase-detected by, for example, a PLL circuit, and a sync and an address modulation code are demodulated. In this PLL circuit, a wobble clock with one wobble wave (a waveform of one cycle of a sine wave) as one clock is also extracted.
JP 2004-355757 A

  In order to extract an address modulation code (physical address) from the demodulated wobble signal, a sync in the wobble signal is detected, and for example, a wobble clock is counted with a counter on the basis of the sync position. A method (synchronization process) of extracting the physical address in Therefore, in order to correctly extract the physical address, it is important to detect the sync at the correct sync position without erroneously detecting the sync.

  However, if the waveform of the wobble signal is distorted due to the influence of noise, transfer characteristics, etc., and sync is not detected at the correct position, synchronization processing may occur at the incorrect position. For example, there is a possibility of erroneous sync detection in which a signal that is not a sync is detected as a sync due to distortion of the wobble waveform. Conventionally, in order to prevent sync error detection, a method of providing a detection window at the expected sync position has been taken, but when a pattern that causes sync error detection (such as a pattern similar to a sync) appears at the same period as the sync In this case, since the detection window is not canceled, a true sync cannot be detected.

  On the other hand, the true sync pattern may collapse and sync detection may not be possible. In order to avoid this, the sync pattern is determined to be a soft decision rather than a strict match determination so that even a slightly distorted sync can be detected (for example, a single mismatch in the sync pattern determination interval is allowed). However, depending on how the sync pattern breaks down, it may be detected that the position is shifted back and forth from the true sync position.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical disc apparatus capable of detecting a sync pattern of a wobble signal with high reliability, and a control method therefor.

  In order to solve the above-described problem, an optical disc apparatus according to the present invention, in an optical disc apparatus that extracts a binary phase modulated wobble signal from a wobble formed on a recording surface of the optical disc, phase-detects the wobble signal to obtain wobble data. A phase detection unit that generates a sync signal, a sync detection unit that detects a sync signal from the wobble data using a reference sync pattern, a position of the detected sync signal, and a cycle of the sync signal A first protection window generation unit that generates a first protection window from one period, and a second protection window that repeats at a second period from the wobble data at a position where the sync signal should appear. 2 when the sync signal detected by the protection window generation unit and the sync detection unit is within the first protection window and the second protection window. A sync signal determination unit for determining a sync signal, in synchronization to the determined said sync signal, characterized in that and an address extraction unit which extracts the physical address information contained in the wobble data.

  In order to solve the above-mentioned problem, an optical disk device control method according to the present invention is an optical disk device control method for extracting a binary phase modulated wobble signal from a wobble formed on a recording surface of an optical disk. Phase detection of the signal, generation of wobble data, detection of a sync signal from the wobble data using a reference sync pattern, and detection of a position of the sync signal and a cycle of the sync signal A first protection window is generated from one cycle, a second protection window that repeats in a second cycle is generated from the wobble data at a position where the sync signal should appear, and the detected sync signal is Determining the sync signal when in the first protection window and the second protection window, synchronizing the sync signal with the determined sync signal, It extracts the physical address information contained in the wobble data, characterized by comprising a Suttepu.

  According to the optical disc device and the control method thereof according to the present invention, the sync pattern of the wobble signal can be detected with high reliability.

  An optical disc device 1 according to an embodiment of the present invention and a control method thereof will be described with reference to the accompanying drawings.

(1) Configuration FIG. 1 is a diagram illustrating a configuration example of an optical disc apparatus 1 according to the present embodiment. The optical disc apparatus 1 records and reproduces data with respect to an optical disc 100 that can record and reproduce. Examples of the optical disc 100 that can be recorded and reproduced include DVD + R and DVD + RW.

  The optical disc apparatus 1 is connected to a host computer 101 such as a personal computer.

  When recording data on the optical disc 100, the recording data is input from the host computer 101 to the recording unit 4 via the interface 3. The recording unit 4 performs processing such as code modulation on the recording data, and then outputs it to the pickup 5. The pickup 5 outputs laser light with a recording laser power from a built-in laser oscillator, and pits are formed on the recording surface of the optical disc 100.

  When data recorded on the optical disc 100 is reproduced, the recording surface of the optical disc 100 is irradiated with a reproduction laser power. Reflected light from the optical disk 100 is output as an RF signal from the pickup 5, and after being subjected to level adjustment or the like by an RF amplifier, is input to the reproducing unit 7. The reproduction unit 7 demodulates the RF signal, further performs code demodulation, error correction, and the like, and then outputs reproduction data to the host computer 101 via the interface 3.

  In the recording / reproducing optical disc 100, a groove having a sine wave-like wave called wobble is formed. In this wobble, physical address information on the optical disk 100 is binary-phase modulated and embedded.

  The wobble waveform is extracted by the RF amplifier 6 and input to the physical address detector 10 as a wobble signal. The physical address detected by the physical address detection unit 10 is output to the control unit 8 and used at the time of recording or reproduction.

  The control unit 8 controls the entire optical disc apparatus 1.

  FIG. 2 is a diagram illustrating a detailed configuration example of the physical address detection unit 10 according to the present embodiment.

  The physical address detection unit 10 includes a phase detection unit 20, a wobble PLL unit 21, a sync detection unit 22, a first protection window generation unit 23, a sync signal determination unit 24, a second protection window generation unit 30, a flywheel counter (4836 waves). Period) 27, an address extraction unit 28, and the like.

  The sync signal determination unit 24 includes a first AND circuit 25 and a second AND circuit 26 therein.

  The second protection window generator 30 includes a rising edge detector 31, a rising edge integrator 32, a two-period flag generator 33, a two-phase phase inverter 34, and the like.

  The operation of each component of the physical address detector 10 is closely related to the nature of the input wobble signal. Before describing the operation of each component, the wobble signal will be described.

  FIG. 3 explains wobble modulation rules in DVD + R and DVD + RW. FIG. 3 (a) shows the unmodulated wobble as PW (Positive Wobble), and FIG. 3 (b) shows the modulated wobble as NW (Negative Wobble: negative phase, unmodulated wobble). The phase difference is 180 °. The wobble signal represents a sync or an address modulation code by combining PW and NW.

  FIG. 4 shows the configuration of an ADIP word (ADress In Pre-groove word), which is a unit to which a physical address is allocated. The ADIP word is composed of 52 sets of units. As a breakdown, the “sync unit” located at the head of the ADIP word has synchronization information, and the subsequent 51 units “data unit” have address modulation code information. One unit is composed of 93 wobbles, the first 8 waves are ADIP, and the remaining 85 waves are unmodulated waves. Therefore, the ADIP word is composed of wobble 93 waves × 52 units = 4836 waves. Further, one ECC block, which is a recording unit, is composed of four ADIP words.

  Since “sync unit” and “data unit” are embedded at fixed relative positions on the optical disc 100, by specifying the head of the ADIP word, that is, the head position of “sync unit”, the following 51 sets The reading timing of the address modulation code on the “data unit” can be taken for each ADIP word. Therefore, it is very important to detect an accurate sync from the optical disc 100 using the “sync unit”.

  One ADIP word has one physical address and disk auxiliary information by combining 51 sets of “data unit” address modulation codes. One set of “data unit” represents one bit of data, and one ADIP word can represent 51 bits of data.

  The breakdown of physical address information represented by ADIP word in DVD + R and DVD + RW is “reserved” 1 bit, “physical address: 22 bits”, “disk auxiliary information: auxiliary information about the disc” 8 bits, And “error correction parities” are 20 bits, for a total of 51 bits.

  The disk auxiliary information represents a set of 32 ADIP words, that is, 32 × 8 bits = 256 bits. The disc auxiliary information is auxiliary information of the optical disc 100, for example, information such as the size of the disc.

  FIG. 5 is a diagram for explaining an ADIP pattern common to the sync unit and the data unit.

  Both the sync unit and the data unit are composed of 93 wobble waves, and each head wobble 8 wave portion is called “ADIP”. A part of this part is modulated (NW) to represent a sync pattern and an address modulation code. The wobble 85 waves following “ADIP” 8 waves are all composed of PW as a non-modulation region.

  FIG. 6 is a diagram illustrating “ADIP” of sync unit and data unit (eight wobble waves at the head of each unit).

  Among these, FIG. 6A shows a sync pattern, in which the first four wobble waves of “ADIP” of the sync unit are modulated to NW, and the subsequent four waves are unmodulated PW.

  FIG. 6B shows the ADIP of the data unit when the data is “0”, and FIG. 6C shows the ADIP of the data unit when the data is “1”.

  The first four waves are common to both “0” and “1” data, and the first one wave is NW and the following three waves are PW to identify the ADIP head in the data unit. , So that they can be identified.

  The latter four waves differ depending on whether the data is “0” or “1”. Of the 4 waves in the latter half, when the front 2 waves are PW and the back 2 waves are NW, the data represents “0”. Conversely, when the front 2 waves are NW and the back 2 waves are PW, the data “1” is displayed. Represents.

  These sync unit and data unit waveforms are phase-detected by the phase detector 20.

  FIG. 7 is a diagram illustrating an internal configuration example of the phase detection unit 20 and an internal configuration example of the wobble PLL unit 21 related thereto.

  A phase error between the wobble signal and the COS reference 212 is generated by the phase detector 211 of the wobble PLL unit, and the phase error becomes a control signal for the VCO 215 via the loop filter 214. The frequency and phase of the VCO 215 are controlled so that the phase error approaches zero.

  When the phase is locked, the PW of the wobble signal and the COS reference 212 are orthogonal (90 degrees out of phase). The wobble clock generated from the VCO 215 also has a frequency that matches the frequency of the wobble signal.

  On the other hand, the wobble PLL unit 21 also generates a SIN standard 213 orthogonal to the COS standard 212. The SIN reference 213 is input to the phase detector 20 and is phase-detected with the wobble signal by the phase detector 201.

  When the wobble PLL unit 21 is locked, the PW of the wobble signal and the SIN standard 213 are in phase.

  FIG. 8 is a diagram illustrating the concept of phase detection of the wobble signal and the SIN reference 213. When the wobble signal is PW, it is in phase with the SIN reference 213, and the sum of the sampling data (the A / D circuit is omitted in FIG. 7) by the product-sum circuit 202 is a positive value. On the other hand, when the wobble signal is NW, the relationship is opposite to that of the SIN standard 213, and the result of multiplying and summing the sampling data is a negative value.

  The output of the product-sum circuit 202 is multi-valued data. By binarizing this multi-valued data by the binarizing circuit 203, it can be assigned to “0” or “1” for each wobble wave. Here, PW = “0” and NW = “1” are assigned. This binarized data is wobble data.

  In order to extract the address modulation code (physical address) from the wobble data, the sync in the wobble data is detected, and for example, the wobble clock is counted with a counter on the basis of the sync position, and the physical at a predetermined position from the sync position. A method of extracting addresses (synchronization processing) is used.

  However, as described above, when the waveform of the wobble signal is distorted due to the influence of noise, transfer characteristics, or the like, and the sync is not detected at the correct position, the synchronization process may be performed at the incorrect position. For example, there is a possibility of erroneous sync detection in which a signal that is not a sync is detected as a sync due to distortion of the wobble waveform. Conventionally, in order to prevent erroneous sync detection, a method of providing a protection window (first protection window) at the expected sync position has been used. However, a pattern that causes sync error detection (such as a pattern similar to a sync) is a sync. , The detection window is not released, and a true sync cannot be detected. On the other hand, the true sync pattern may collapse and sync detection may not be possible.

  As described above, sufficiently reliable sync detection cannot always be realized only by the first protection window.

  The point of the present invention lies in that a second protection window is generated in addition to the conventional first protection window, and that two sink windows enable reliable sink detection. Furthermore, the first protection window is generated with reference to the position of the detected sync signal, whereas the second protection window is synchronized only from the input wobble data string without using the sync signal. It is characterized in that a protective window is generated at a position that is synchronized with the position. That is, the second protection window provides a protection window that is not affected by the case where the sync signal itself fluctuates due to noise or the like.

(2) Operation Hereinafter, a method for controlling the optical disc apparatus 1, particularly, a sync detection and physical address detection method including the first and second protection window generation methods will be described.

  FIG. 9 is a flowchart illustrating a processing example of the physical address detection method according to the present embodiment. Step ST1 is a process of detecting the phase of the wobble signal and binarizing it.

(3) Sync detection Step ST2 is a process for detecting a sync from binarized wobble data.

  FIGS. 10 and 11 are diagrams for explaining the processing contents of sync detection. FIG. 10 shows an example when no sync is detected, and FIG. 11 shows an example when a sync signal is detected. .

  FIG. 10A shows the phase detection waveform of the wobble signal, and FIG. 10B shows the waveform after binarization (wobble data). FIG. 10C shows a reference sync pattern, which is a pattern for the first eight waves of the sync unit. As shown in FIG. 6A, this is a pattern in which NW has four consecutive waves and then PW has four consecutive waves.

  The range of the reference sync pattern spread (the range of 8 wobble waves) is the sync pattern comparison range. A pattern match flag is set on the assumption that a sync has been detected when the reference sync pattern matches the wobble data in all the ranges. In the example of FIG. 10, since there is a mismatch in only one wobble, no sync is detected, and no pattern match flag is set.

  On the other hand, in FIG. 11, since the reference sync pattern and the wobble data match in the entire sync pattern comparison range, a pattern match flag is set on the assumption that a sync has been detected.

(4) First Protection Window Generation In step ST3, a first protection window is generated.

  Once a sync is detected, the sync protection window (first protection window) can be set after 4836 wobble periods (first period) defined as the period of the sync signal from the sync detection position.

  FIG. 12 is a diagram illustrating a situation in which a protective window is provided in the range of one wobble before and after the position after 4836 wobbles from the sync detection position.

  A sync detection signal is input as a reset signal of the flywheel counter 27 (see FIG. 2), and is counted up using a wobble clock. Based on this count value, the first protection window generator 23 generates a first protection window. The generated first protection window is input to the sync signal determination unit 24.

(5) Second Protection Window Generation On the other hand, a two-cycle flag (second protection window) is generated in a system different from the first protection window generation (step ST4 in FIG. 9).

  The two-cycle flag (second protection window) is a protection window that is directly generated from wobble data regardless of the sync signal. The basic idea of the second protection window generation is to generate a protection window having this periodicity by paying attention to the periodicity of the phase change point in the wobble signal.

  A specific method will be described below.

  First, pay attention to where the phase change points of sync unit and data unit exist in ADIP. As shown in FIG. 6, when the first wobble of ADIP is set to 0 and the positions of 8 wobble waves are assigned as “ADIP positions 0 to 8”, the appearance locations of the sync unit and data unit phase edges are summarized below.

Sync unit rising edge: “ADIP position 0th wave”
data unit Data 0 rising edge: “ADIP position 0th wave and 6th wave”
data unit Data 1 rising edge: “ADIP position 0th wave and 4th wave”

Sync unit falling edge: “ADIP position 4th wave”
Data unit Data 0 falling edge: “ADIP position 1st wave and 8th wave”
Data unit Data 1 falling edge: “ADIP position 1st wave and 6th wave”
Here, the rising edge refers to the changing point from PW to NW, and the falling edge refers to the changing point from NW to PW.

  The appearance position of the phase edge that combines the rise and fall does not have the periodicity common to all units. However, if it is limited to the rising edge, it can be seen that it appears in the even wave in all units. In other words, if considered only within the unit, the rising edge is always on the 2 wobble cycle (2T cycle if 1 wobble cycle is T).

  Now consider the period of rising edges throughout the ADIP word. Since 1 unit is composed of 93 wobbles, the head of ADIP is 93 wobble cycles (odd cycles). Therefore, when considering the 2-wobble period phase, the 2-wobble period phase of the rising edge is alternately switched for each unit. That is, in the even-numbered unit and the odd-numbered unit, the head of ADIP becomes another two-wobble period phase, so that all the rising edges through the ADIP word do not ride on the same two-wobble period phase.

  Therefore, if the phase of the 2 wobble period is switched every time the unit changes, the rising edge always rides the phase of the same 2 wobble period.

  As mentioned above, the unit is composed of 8 wobble ADIP and 85 wobble unmodulated area (monotone wobble), so this unmodulated area is detected once for each ADIP unit. If replacement is performed, two wobble cycles of rising edges have the same phase between consecutive units.

  However, in order to realize this, if the unmodulated area cannot be detected, the 2-wobble period phase cannot be switched for each unit, and if two 2-wobble period phases are mistakenly replaced by one ADIP unit, the original Therefore, it is necessary to make sure that the ADIP unit can perform two wobble cycle phases once.

  Hereinafter, a specific method will be described with reference to the second protection window generation unit 30 in FIG. 2 and the timing chart in FIG.

  First, the rising edge detection unit 31 in FIG. 2 divides the phase detection signal read from the optical disc into one phase in two cycles in order to sum up where the rising edges appear in the two wobble period phases. That is, as shown in FIG. 13C, each wobble wave is sequentially divided into A, B, A, B, A, B. The two periods are sorted in order from the start of circuit operation.

  The rising edge detection unit 31 detects a rising edge. At this time, the rising edge of the sync unit or the rising edge of the data unit is not distinguished, and all the rising edges are detected in the same manner. The judgment of the rising edge is made at the phase change point from the positive phase to the negative phase, that is, the position changed from PW to NW.

  In the two-cycle phase inverting unit 34 in FIG. 2, a process of replacing the two-wobble cycle phase with a non-modulation region for each unit is performed.

  Specifically, when the wobble continuous for a predetermined threshold or more is PW, the two wobble cycle phases are switched. As shown in FIG. 13C, the phase that repeats in two wobble periods such as “A”, “B”, “A”, “B”, “A”, “B”. It is inverted at any one of them to be “A”, “B”, “B”, “A”, “B”, “A”. In that case, in order not to mistakenly replace the PW included in the ADIP of data “0” (PW is continuous for 5 waves; see FIG. 6B), at least 5 consecutive PWs should not be determined as the non-modulation region. Be careful. For example, it is a method of “if the PW continues 30 waves for the first time in the unit, it is determined as an unmodulated region and the two wobble period phases are switched”. In addition, a counter that counts the timing at which the two wobble period phases are switched may be separately provided.

  Next, processing of the rising edge integration unit 32 will be described.

  It is counted whether the rising edge appears in the two wobble period phases “A” and “B”, and the two wobble period phase where many rising edges appear is defined as an “edge concentration point”. As a method for counting up the rising edges, for example, a counter is prepared for each of “A” and “B”, and a method of counting up the numerical values where the rising edges are detected can be considered. FIG. 13D shows the integration of the number of rising edges that appear when “A”, and FIG. 13E shows the integration of the number of rising edges that occur when “B”. .

  The rising edge in the continuous phase detection signal is concentrated on one of the two wobble period phases A and B if the two wobble period phases can be correctly switched for each unit.

  An example of the integration result is shown in FIG. In the example shown in FIG. 14, rising edges of 2 wobble period phase “A” are concentrated.

  In the rising edge integration unit 32, a two-wobble period phase where rising edges are concentrated is determined. In the example of FIG. 14, the wobble period phase is “A”.

  The two-cycle flag generator 33 sets a two-cycle flag at the position of the two-wobble cycle phase “A” based on the determination result of the rising edge integrator 32. This two-cycle flag is the second protection window.

  However, as illustrated in FIG. 14, there is a possibility that part of the rising edge appears in the 2-wobble period phase “B” due to the influence of noise or the like. If the number of rising edges is the same, whether the phase of “A” or “B” is used as the “edge concentration point” is newly aligned with the method of continuing the conventional 2-wobble period phase. Any method of changing to the two-wobble period phase may be used. Moreover, you may comprise either so that selection is possible. Furthermore, it is conceivable to set a two-cycle flag for both “A” and “B” only when the number is the same.

  In addition, the rising edge counting range that determines the new edge concentration point counts all rising edges from the circuit operation start point to the present time, but every time a new result is obtained using an IIR filter, etc. A method of discarding little by little from the result or a method of preparing a flag for limiting the totaling range and totaling only rising edges that appear when this flag is valid may be used. Alternatively, a flag for resetting the counting result may be prepared.

  In addition to the edge concentration point, a “rising edge dispersion degree” signal indicating how much the difference between the edge concentration point and the other two-wobble period phase may be provided. For example, comparing the counter difference between A and B that counts rising edges, “there is a big difference in the edge concentration point count results of 2 wobble cycle phases A and B” or “2 wobble cycle phases“ A ”and“ B ” The edge concentration point aggregation result of “is balanced”. Using this “rising edge dispersion degree”, for example, only when there is a large difference in the result of counting the edge concentration points of the periodic phases “A” and “B”, the edge concentration point is set to one of “A” or “B”. Limitation may be applied, such as limiting to two (in case of equilibrium, a two-cycle flag is set for both).

  The two-cycle flag (second protection window) is set every two wobble cycles (2T: second cycle) unless the edge concentration point changes to the other two-wobble cycle phase due to bit slip or the like.

  However, immediately after startup, when the number of rising edges is small, a highly accurate edge concentration point cannot be obtained, so a threshold value (hereinafter referred to as “two-cycle flag threshold”) is provided for determining the number of rising edges. Limit is set so that the two-cycle flag is disabled until the number of rising edges exceeds the two-cycle flag threshold. The two-cycle flag threshold value may be set externally. In the example of FIG. 13, since the two-cycle flag threshold is “3” (see FIG. 13F), the counter of the two-wobble cycle phase A (see FIG. 13D) becomes “3” to 2 The cycle flag is output.

  Note that the timing at which the two-period flag generation unit 33 takes in the edge concentration point (“A” or “B”) that is the output of the rising edge integration unit 32 is always set to the edge concentration point as a result of counting the rising edges in real time. They may be taken in one by one or at specific time intervals.

  In the above description, the phase change point from the positive phase to the negative phase is set to the position changed from PW to NW, and the number of phase change points is divided into “A” and “B” and counted.

  As an alternative method, the phase change point from the positive phase to the negative phase is determined using the differential value of the phase detection value (multivalue), and the differential value at the phase change point is divided into “A” and “B”. It is also possible to use the method of integrating. As shown in FIG. 10A, the phase detection value (multivalue) changes greatly from a positive value to a negative value when it changes from PW to NW (for example, at the head of the sync pattern), and a differential value. (Difference value) is a large positive value. It is possible to determine the phase change point from the positive phase to the negative phase by determining this differential value with a predetermined threshold.

  The two-cycle flag (second protection window) generated in this way is input to the sync signal determination unit 24 (see FIG. 2).

  FIG. 15 is a flowchart summarizing the method for generating the second protection window described above. First, in step ST11, a rising edge that is a change point from PW to NW is detected.

  On the other hand, in step ST12, it is determined whether or not it is the timing for switching the two-period phases “A” and “B” for each unit. This timing determination is, for example, determined as a timing to replace the time point when 30 PWs continue.

  If it is determined that it is the replacement timing, the two-period phases “A” and “B” are switched (step ST13). By this replacement, even when the units are continuous, the rising edge is concentrated on either of the two period phases “A” and “B”, that is, the periodicity of the rising edge is ensured.

  Step ST14 is a process of adding up the number of appearances of rising edges in each of the two period phases “A” and “B”. If the two-period phases “A” and “B” are exchanged normally, the appearance position of the rising edge should be concentrated on one of the two-period phases “A” and “B”.

  Finally, one of the two period phases (“A” or “B”) in which the appearance of rising edges is concentrated is selected and used as the second protection window (two period flag).

(6) Confirmation of Sync Signal The sync signal detected by the sync detection unit 22 is input to the sync signal detection unit 24, ANDed with the first protection window by the first AND circuit 25, and further the second AND circuit 26 is ANDed with the second protection window. That is, when a sync signal is detected in the first protection window and the second protection window, it is determined as a true sync signal.

  FIG. 16 is a diagram schematically illustrating a sync signal determination state. For example, when a sync signal is detected at a position shifted by 1 wobble back and forth from the true sync position due to noise or the like, it is detected only by the first protection window, but detection is eliminated by the second protection window. FIG. 5 shows that the sync signal is determined only when the sync signal is detected at the true position (the center of the first protection window).

  Returning to FIG. 9, the determination of the sync signal is performed in step ST5. When the sync signal is determined, the flywheel counter (4836 wave period) 27 is reset at the determined sync signal timing (Yes in step ST5).

  On the other hand, during the period when the sync signal is not determined (No in step ST5), the flywheel counter (4836 wave period) 27 continues to count up in units of wobble clocks.

  Since the output of the flywheel counter (4836 wave period) 27 is repeatedly counted up for each ADIP word, the address modulation code (physical address) included in the ADIP word can be extracted.

  According to the present embodiment, focusing on the characteristic that the phase change point of the wobble signal has periodicity, the position where the sync signal should appear is narrowed down to one half of the entire range by using the periodicity. A window (second protective window) is generated. In addition to the protection window (first protection window) generated from the conventional sync signal, the masking effect by the second protection window further prevents synchronization at an incorrect position different from the true sync position, and ensures reliability. Highly wobble address coding can be realized.

  The description so far relates to the detection of sync patterns provided in ADIP word units composed of 4836 wobbles. On the other hand, even in a unit unit composed of 93 wobbles, as shown in FIGS. 6B and 6C, there is a common “unit head pattern” at the head. It is also possible to detect this “unit head pattern” and synchronize each unit using a flywheel counter having a 93 wave period.

  Also in this case, the second protection window can be generated based on the same concept, and the reliability of detection of the “unit head pattern” can be improved. FIG. 17 is a diagram illustrating a configuration example in that case.

  As described above, according to the optical disc apparatus and the control method thereof according to the present embodiment, the sync pattern of the wobble signal can be detected with high reliability.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements over different embodiments may be appropriately combined.

1 is a diagram illustrating a configuration example of an optical disc device according to an embodiment of the present invention. The figure which shows the detailed structural example of a physical address detection part. The figure explaining the wobble modulation rule in DVD + R and DVD + RW. The figure which shows the structure of ADIP word (ADress In Pre-groove word) which is a unit by which the physical address is allocated. The figure explaining the pattern of ADIP common to a sync unit and a data unit. The figure which shows "ADIP" (for the wobble 8 waves of the head of each unit) of sync unit and data unit. The figure which shows the internal structural example of a phase detection part, and the internal structural example of the wobble PLL part relevant to this. The figure which shows the concept of a wobble signal and the phase detection of a SIN reference | standard. 6 is a flowchart illustrating a processing example of a physical address detection method according to the embodiment. It is a figure explaining the processing content of a sync detection, and is a figure which shows the example in case a sync is not detected. It is a figure explaining the processing content of a sync detection, and is a figure which shows the example when a sync signal is detected. The figure which shows the condition which provides a protection window in the range of 1 wobble before and after centering on the position after 4836 wobble from a sync detection position. The timing chart explaining the 2nd protection window production | generation method. The figure which shows an example of the rising edge appearance number integration result with respect to 2 wobble period phases A and B. The flowchart which shows an example of the production | generation method of a 2nd protection window. The figure which shows typically the condition of the confirmation of a sync signal. The figure which shows the structural example at the time of applying this embodiment to the method of detecting "unit head pattern" and synchronizing for every unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk apparatus 4 Recording part 7 Playback | regeneration part 8 Control part 10 Physical address detection part 20 Phase detection part 21 Wobble PLL part 22 Sink detection part 23 1st protection window production | generation part 24 Sink signal determination part 28 Address extraction part 30 2nd protection window Generator

Claims (18)

In an optical disc apparatus for extracting a binary phase modulated wobble signal from a wobble formed on a recording surface of an optical disc,
A phase detector for detecting the phase of the wobble signal and generating wobble data;
A sync detector that detects a sync signal from the wobble data using a reference sync pattern;
A first protection window generator that generates a first protection window from the detected position of the sync signal and a first period defined as the period of the sync signal;
A second protection window generation unit that generates a second protection window that repeats in a second cycle from the wobble data at a position where the sync signal should appear;
A sync signal determination unit that determines the sync signal when the sync signal detected by the sync detection unit is within the first protection window and the second protection window;
An address extraction unit for extracting physical address information included in the wobble data in synchronization with the determined sync signal;
An optical disc apparatus comprising: The wobble signal is a signal having a periodicity at least one of a phase change point from a positive phase to a negative phase and a phase change point from a negative phase to a positive phase,
The second protective window generator is
Generating a second protective window having a period of the phase change point as a second period;
The optical disc apparatus according to claim 1, wherein: The wobble signal has a periodicity at the phase change point from the positive phase to the negative phase, or has a non-modulation region of a predetermined length, and the phase is inverted in the non-modulation region to change from the positive phase to the negative phase. It is a signal that can give periodicity to the phase change point of
The second protective window generator is
Generating a second protective window having a period of the phase change point as a second period;
The optical disc apparatus according to claim 1, wherein: The period of the phase change point is 2T, where T is the period of the wobble 1 wave.
The optical disc apparatus according to claim 3, wherein The second protective window generator is
The wobble data is alternately divided into a first period and a second period for each period T of the wobble wave,
Integrating the number of phase change points in the first period and the second period,
Generating the second protection window based on a period with a larger number of accumulated phase change points;
5. The optical disc apparatus according to claim 4, wherein Generating the second protection window when the accumulated number of phase change points exceeds a predetermined threshold;
6. The optical disk apparatus according to claim 5, wherein The second protective window generator is
The wobble data is alternately divided into a first period and a second period for each period T of the wobble wave,
The differential value of the phase detection signal at the phase change point is integrated in the first period and the second period,
Generating the second protection window based on a period with a larger accumulated differential value;
5. The optical disc apparatus according to claim 4, wherein The wobble signal is a signal having a non-modulation region of a predetermined length and having a periodicity at the phase change point from the positive phase to the negative phase by inverting the phase in the non-modulation region,
The second protective window generator is
When the non-modulation period continues for a predetermined threshold or more, the phase of the wobble data is inverted, thereby giving periodicity to the phase change point from the positive phase to the negative phase.
5. The optical disc apparatus according to claim 4, wherein The optical disc is DVD + R or DVD + RW.
5. The optical disc apparatus according to claim 4, wherein In a control method of an optical disc apparatus for extracting a binary phase modulated wobble signal from a wobble formed on a recording surface of an optical disc,
Phase detection of the wobble signal to generate wobble data;
Detect a sync signal from the wobble data using a reference sync pattern,
Generating a first protection window from the detected position of the sync signal and a first period defined as the period of the sync signal;
A second protection window that repeats in a second cycle is generated from the wobble data at a position where the sync signal should appear,
Determining the sync signal when the detected sync signal is within the first protection window and the second protection window;
Synchronizing with the determined sync signal to extract physical address information included in the wobble data,
An optical disk apparatus control method comprising a step. The wobble signal is a signal having a periodicity at least one of a phase change point from a positive phase to a negative phase and a phase change point from a negative phase to a positive phase,
In the step of generating the second protection window,
Generating a second protective window having a period of the phase change point as a second period;
11. The method of controlling an optical disk device according to claim 10, wherein The wobble signal has a periodicity at the phase change point from the positive phase to the negative phase, or has a non-modulation region of a predetermined length, and the phase is inverted in the non-modulation region to change from the positive phase to the negative phase. It is a signal that can give periodicity to the phase change point of
In the step of generating the second protection window,
Generating a second protective window having a period of the phase change point as a second period;
11. The method of controlling an optical disk device according to claim 10, wherein The period of the phase change point is 2T, where T is the period of the wobble 1 wave.
The method of controlling an optical disc apparatus according to claim 12, wherein: In the step of generating the second protection window,
The wobble data is alternately divided into a first period and a second period for each period T of the wobble wave,
Integrating the number of phase change points in the first period and the second period,
Generating the second protection window based on a period with a larger number of accumulated phase change points;
14. The method of controlling an optical disk device according to claim 13, Generating the second protection window when the accumulated number of phase change points exceeds a predetermined threshold;
15. The method of controlling an optical disk device according to claim 14, wherein In the step of generating the second protection window,
The wobble data is alternately divided into a first period and a second period for each period T of the wobble wave,
The differential value of the phase detection signal at the phase change point is integrated in the first period and the second period,
Generating the second protection window based on a period with a larger accumulated differential value;
14. The method of controlling an optical disk device according to claim 13, The wobble signal is a signal having a non-modulation region of a predetermined length and having a periodicity at the phase change point from the positive phase to the negative phase by inverting the phase in the non-modulation region,
In the step of generating the second protection window,
When the non-modulation period continues for a predetermined threshold or more, the phase of the wobble data is inverted, thereby giving periodicity to the phase change point from the positive phase to the negative phase.
14. The method of controlling an optical disk device according to claim 13, The optical disc is DVD + R or DVD + RW.
14. The method of controlling an optical disk device according to claim 13,

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