JP4001944B2 - Disk unit - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a disk device, for example, in a magneto-optical disk device, by supplying a prescribed drive signal to a PLL (Phase Locked Loop) circuit that generates the reproduction clock during a period in which the reproduction clock cannot be generated correctly. Stabilizes circuit operation and shortens pull-in time.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an optical disc apparatus, desired data is recorded and reproduced in a prescribed sector unit with reference to position information recorded on a magneto-optical disc.
[0003]
For this reason, in this type of magneto-optical disk, a marker indicating the start position of the sector, a reference signal serving as an operation reference for the PLL circuit, and address data indicating the position information of each sector are recorded in advance by precoding. To be formed. On the other hand, the optical disk apparatus locks the PLL circuit with the reference signal, reproduces the subsequent address data with reference to the reproduction clock obtained from the PLL circuit, and thereby confirms the recording / reproducing position. .
[0004]
[Problems to be solved by the invention]
However, in the conventional optical disc apparatus, the operation of the PLL circuit becomes unstable during a period in which the laser beam scans an unrecorded area or the like, and when the reference signal is input at the head of each sector, There is a problem that the pull-in time until the phase synchronization becomes long.
[0005]
In other words, this type of optical disk apparatus records desired data in the subsequent data recording area after confirming the recording / reproducing position in the corresponding sector at the time of recording. Therefore, when recording this data, the PLL circuit is held in a state in which no reference reproduction signal is input in the data recording area. Further, when the data recording area is not recorded, even in the reproduction mode, the PLL circuit is held in a state where no reference reproduction signal is inputted.
[0006]
On the other hand, this type of PLL circuit compares the phase of the reproduced signal with the clock, and feeds back the phase comparison result to the voltage-controlled oscillation circuit for generating a clock as an error voltage, so that the reproduced signal as a reference can be obtained. Is no longer input, the voltage controlled oscillation circuit is held in a so-called free-run state. That is, during these periods, the PLL circuit shifts the frequency of the clock output from the voltage-controlled oscillation circuit to the free-running frequency, and returns to the correct frequency when the reproduction signal is input again. .
[0007]
In an optical disk apparatus, this PLL circuit has a large pull-in range and holding range so that it can sufficiently compensate for eccentricity of the magneto-optical disk, jitter of the spindle motor, and the like. The frequency variable range of the oscillation circuit is also set to a relatively large range. Therefore, when noise or the like is mixed in such a state that the voltage controlled oscillation circuit is held in a so-called free run, the clock frequency greatly fluctuates due to this noise.
[0008]
In practice, noise is randomly generated in an unrecorded area or the like, and the PLL circuit becomes unstable in response to the random noise during a period in which it is held in a free-run state, and oscillates. The frequency will fluctuate greatly. Accordingly, the time required for the reproduction signal to be input again to return to the correct frequency is increased accordingly. In particular, in this type of magneto-optical disk, the precoded area of the reference signal or the like is as small as about 1% of the whole, and therefore, in the optical disk apparatus, there is a period during which a reproduction signal serving as an operation reference is not input to the PLL circuit. There is a drawback that this period is long and random. Accordingly, there is a drawback that the frequency fluctuation of the PLL circuit due to the influence of noise or the like is large.
[0009]
If the pull-in time becomes longer in this way, the magneto-optical disk needs to increase the recording area of the reference signal accordingly, and the recording density will decrease.
[0010]
The present invention has been made in consideration of the above points, and an object of the present invention is to propose a disk device capable of stably maintaining the operation of this type of PLL circuit and reducing the pull-in time.
[0011]
[Means for Solving the Problems]
  To solve this problem,The present inventionA reproduction signal obtained from a disk-shaped recording medium is supplied to a PLL circuit, a clock is generated by the PLL circuit based on a precode signal recorded intermittently on the disk-shaped recording medium, and the clock is used as a reference. Detects position information of the disc-shaped recording medium, and records desired data based on the detection resultIn the disk device, the signal level of the reproduction signal obtained from the disk-shaped recording medium is monitored, and the period during which the signal level of the reproduction signal falls is detected,During a no-signal period during which the reproduction signal of the pre-coded signal cannot be obtained.A no-signal detection circuit that outputs a detection signal whose signal level rises, and detects the pre-coded signal, generates and outputs a prescribed drive signal based on the detection timing, and outputs the disc-shaped recording medium Controlled by a timing generator that outputs a timing signal whose signal level rises during a period during which the user area is recorded and erased, an OR circuit to which the detection signal and the timing signal are supplied, and an output signal of the OR circuit The playback signal obtained from the disc-shaped recording medium and the specified drive signal generated by the timing generator are selected, and the specified signal is replaced with the playback signal during the period when the signal level of the output signal of the OR circuit rises. And a selection circuit for supplying the drive signal to the PLL circuit.
[0014]
[Action]
  In the present invention,During a no-signal period in which a pre-coded signal reproduction signal cannot be obtained from the disk-shaped recording medium,A selection circuit is controlled by an output signal of an OR circuit to which a detection signal in which the signal level rises and a timing signal in which the signal level rises is supplied during a period of recording and erasing the user area of the disc-shaped recording medium, The playback signal obtained from the disc-shaped recording medium and a predetermined drive signal generated based on the detection timing of the precode signal by the timing generator are selected, and the signal level of the output signal of the OR circuit rises During the period,Instead of playback signalSaidSupply the specified drive signal to the PLL circuitSoThe operation of the PLL circuit can be stably maintained, and clock fluctuation can be effectively avoided. Therefore, when a subsequent precode signal is input, it can be locked in a short time.Further, regarding the gap formed between the recording area of the precode signal recorded by this kind of precoding and the recording area of the subsequent data, and at the time of data writing, during the period of writing this data, The operation of the PLL circuit can be stably maintained, and clock fluctuation can be effectively avoided.
[0016]
  further,The signal level of the reproduction signal is monitored, and the previous drive signal is supplied to the PLL circuit instead of the reproduction signal during the previous no-signal period based on the monitoring result.ByWith respect to an unrecorded area where no data is recorded, the operation of the PLL circuit can be stably maintained, and clock fluctuation can be effectively avoided.
[0017]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
[0018]
(1) Configuration of the embodiment
FIG. 2 is a block diagram showing an optical disc apparatus according to an embodiment of the present invention. The optical disk apparatus 1 records image data on a multi-zone magneto-optical disk 2 and reproduces and outputs the image data recorded on the magneto-optical disk 2. In this embodiment, the optical disc apparatus 1 has four optical blocks 3 to 6 and four processing systems corresponding to the four optical blocks. However, only one system will be described for simplification of description. .
[0019]
That is, the optical disk apparatus 1 is connected to an external device via a SCSI controller 7 via a SCSI (Small Computer System Interface), and switches its operation in response to a control command input from the external device. The SCSI controller 7 outputs a control command input from the external device to the internal bus BUS, and outputs a response command input from the internal bus BUS to the external device. The SCSI controller 7 outputs image data input from the external device to the error correction circuit 8 during recording, and outputs image data input from the error correction circuit 8 to the external device during reproduction.
[0020]
The error correction circuit 8 adds an error correction code or the like to the image data input from the SCSI controller 7 at the time of recording, converts it to a specified data structure, and generates 1-7 encoded data to generate encoded data The encoded data is output to the RF circuit 9. On the other hand, at the time of reproduction, the error correction circuit 8 converts the encoded data input from the RF circuit 9 into the original data structure contrary to the recording time, and then performs prescribed data processing such as error correction processing. As a result, the image data recorded on the magneto-optical disk 2 is reproduced and output to the SCSI controller 7.
[0021]
The RF circuit 9 outputs the light reception result of the return light obtained from the corresponding optical blocks 3 to 6 to the laser power control circuit 10, and the sector mark recorded on the magneto-optical disk 2 in advance by this return light. Etc., and the timing of recording and reproduction is detected. Furthermore, the RF circuit 9 generates a modulated signal by performing NRZI (Non Return to Zero Inverted) modulation on the encoded data input from the error correction circuit 8 at the time of recording, with reference to the timing detected by the sector mark or the like. This modulated signal is output to the laser power control circuit 10.
[0022]
At the time of reproduction, the RF circuit 9 receives the reproduction signal RF obtained from the corresponding optical blocks 3 to 6, NRZI-demodulates this reproduction signal RF to generate reproduction data, and this reproduction data is sent to the error correction circuit 8. Output.
[0023]
The laser power control circuit 10 holds the light amount of the laser beam L irradiated to the magneto-optical disk 2 from the optical block 3 based on the reception result of the return light input from the RF circuit 9 at a prescribed light amount. Further, the laser power control circuit 10 intermittently changes the light amount of the laser beam L from the light amount at the time of reproduction to the light amount at the time of writing in accordance with the modulation signal input from the RF circuit 9 via the HF superimposing circuit 13 at the time of writing. Launch.
[0024]
The optical block 3 (4 to 6) is formed of a fixed portion 3A fixed to the chassis and a movable portion 3B movable in the radial direction of the magneto-optical disk 2. Among these, the fixed portion 3A has a laser diode 12 that emits a laser beam. During recording, the HF superimposing circuit 13 superimposes a high-frequency signal on the drive signal of the laser diode 12 to reproduce the light quantity of the laser beam L. Start up intermittently from the amount of light to the amount of light at the time of writing.
[0025]
Further, the fixed portion 3A is arranged on the optical axis of the emitted light by emitting the laser beam L emitted from the laser diode 12 through the prism 14 toward the rotation center axis of the magneto-optical disk 2. The laser beam L is supplied to the movable part 3B. Further, after the reflected light of the laser beam L obtained from the movable part 3B is reflected by the prism 14, the fixed part 3A bends the optical path by the prism 15 and receives the light by the prescribed light receiving element 16.
[0026]
The light receiving element 16 is formed with a light receiving surface so that a tracking error signal, a reproduction signal and the like can be formed from the return light, and outputs the light reception result of each light receiving surface to the preamplifier 17. In the preamplifier 17, the fixing unit 3 </ b> A performs current-voltage conversion processing on each output signal of the light receiving element 16, then performs addition / subtraction processing, amplifies it with a specified amplification factor, and outputs it. As a result, the fixed portion 3A supplies the laser beam L to the movable portion 3B and receives the return light obtained from the movable portion 3B to generate a reproduction signal RF, a tracking error signal, a focus error signal, and the like. Has been made.
[0027]
On the other hand, the movable portion 3B is driven by the radial servo circuit 19 so as to be movable in the radial direction of the magneto-optical disk 2 from the specified retraction position, and the optical path of the laser beam L supplied from the fixed portion 3A. After being bent by the prism 20, the light is condensed on the information recording surface of the magneto-optical disk 2 by the objective lens 21. In addition, the movable portion 3B condenses the return light of the laser beam L obtained from the information recording surface by the objective lens 21, and then bends it by the prism 20 and emits it to the fixed portion 3A.
[0028]
Thus, in the optical disc apparatus 1, the amount of the laser beam L is intermittently raised during recording, and a prescribed magnetic field is applied to the irradiation position of the laser beam, thereby applying a thermomagnetic recording technique. In this way, desired data can be recorded. Further, the optical disc apparatus 1 is formed so that a reproduction signal RF whose signal level changes in accordance with the change of the polarization plane of the return light can be obtained from the fixed portion 3A at the time of reproduction, thereby recording using the Kerr effect. Can be played back. Thus, the movable portion 3B, together with the fixed portion 3A, forms a pickup that accesses the magneto-optical disk 2 and outputs a reproduction signal RF.
[0029]
In this movable part 3B, the objective lens 21 is formed so as to be movable up and down and left and right by a drive signal. The tracking servo circuit 24 is controlled by the system control circuit 25 to start operation, and moves the objective lens 21 to the left and right based on the tracking error signal, thereby tracking-controlling the optical block 3.
[0030]
Similarly, the focus servo circuit 26 is controlled by the system control circuit 25 to start up the operation and moves the objective lens 21 up and down based on the focus error signal, thereby controlling the focus of the optical block 3.
[0031]
Thus, in this embodiment, the tracking servo circuit 24 and the focus servo circuit 26 are provided in four systems corresponding to the four optical blocks 3 to 6, and the error correction circuit 8 and the laser power control circuit 10 also have four systems. Four systems are provided corresponding to the optical blocks 3 to 6.
[0032]
The disk servo circuit 27 rotationally drives the spindle motor 28, and thereby rotationally drives the magneto-optical disk 2 chucked on the rotating shaft of the spindle motor 28 under a constant angular velocity.
[0033]
(1-1) Configuration of magneto-optical disk
Here, as shown in FIG. 3, the information recording surface of the magneto-optical disk 2 is concentrically divided by precoding, and the radial direction of the magneto-optical disk 2 is divided into an inner area AR1 and an outer area AR2. The length is set to be approximately equal. Further, in the magneto-optical disk 2, each of the areas AR1 and AR2 is equally divided radially to form 42 sectors, and each sector has a prescribed angle α between the inner area AR1 and the outer area AR2. They are formed so as to be shifted in the circumferential direction only.
[0034]
In the magneto-optical disk 2, the sectors of the inner peripheral area AR1 and the outer peripheral area AR2 are defined as shown in FIG. As a result, when the magneto-optical disk 2 is driven to rotate at a constant angular velocity, the data transfer rate used for recording is increased on the outer peripheral side by the linear velocity that increases in the outer peripheral area AR2, and the inner peripheral side and the outer peripheral side are increased. The linear recording densities are set to substantially equal values in the side areas AR1 and AR2. As a result, the magneto-optical disk 2 is designed to improve the recording density.
[0035]
Here, each sector is formed so that a 55-byte address part formed in advance by precoding is formed at the head, the remaining area is allocated to the user area, and data in a prescribed format is recorded in this user area. Yes.
[0036]
In this address part, a sector mark (SM) and a postamble (PA) are recorded at the head part and the end part, respectively, and the sector mark (SM) represents the start position of the address part which is the start position of the sector. (PA) represents the end of the address part.
[0037]
Further, in this address portion, the reference signal (VFO1, VFO2, VFO3), AND mark (AM1, AM2, AM3), and ID signal (ID1, ID2, ID3) are sequentially and repeatedly recorded three times in the remaining area. Thus, reliability is ensured. Here, the AND mark represents the recording start position of the ID signal, and a burst signal having a specified frequency is assigned to the reference signal, and a reproduction clock can be generated from the reference signal by the PLL circuit.
[0038]
On the other hand, the ID signal is recorded by adding the error correction code (CRC) and 00h data to the track number and sector number data, then performing 1-7 modulation, and further performing NRZI modulation. In the magnetic disk 2, an address indicating a recording / reproducing position can be detected by the ID signal.
[0039]
Thus, the optical disc apparatus 1 detects the start position of the sector based on the sector mark SM, confirms the recording / reproduction position from the ID signal with reference to the reproduction clock CK1 generated from the reference signals VFO1, VFO2, and VFO3, and the subsequent user The desired data is recorded and reproduced in the area.
[0040]
In the user area, a reference signal recording area (VFO4), a data recording area (DATA-AREA), and a buffer area (BUFFER) are formed after the trial writing area (ALPC), and writing is performed using the trial writing area. It is formed so that the amount of light at the time can be adjusted, and is formed so as to record a data clock in the recording area of the reference signal, and the buffer area is held as a blank area.
[0041]
In the data recording area, a recording area (DATA) for recording data of a specified byte together with an error correction code and a resynchronizing area (RESYNC) are alternately arranged after a synchronization pattern area (SYNC) for recording a specified synchronization pattern. Finally, a recording area for dummy bytes 00h is formed.
[0042]
As a result, the linear recording density is set to be substantially equal between the recording area AR1 on the inner circumference side and the recording area AR2 on the outer circumference side. Thus, in the magneto-optical disk 2, the recording area AR1 on the inner circumference side and the outer recording area AR1 The recording area AR2 is formed so that data of 2026 bytes and 2978 bytes can be recorded in this data recording area, respectively.
[0043]
(1-2) Details of signal processing system
FIG. 1 is a block diagram showing the RF circuit 9 and its peripheral circuits. In the optical disc apparatus 1, the PLL circuit 30 inputs the reproduction signal RF output from the preamplifier 17 via the selection circuit 31 built in the RF circuit 9, and inputs the reproduction signal RF to the phase comparison circuit 32. The phase comparison circuit 32 compares the phase of the recovered clock CK1 output from the voltage controlled oscillation circuit (VCO) 33 and the input signal input via the selection circuit 31, and outputs the phase comparison result.
[0044]
The voltage control type oscillation circuit 33 inputs this phase comparison result as an error voltage via a prescribed low-pass filter, and varies the frequency of the reproduction clock CK1 so that this error voltage becomes 0 level. As a result, the PLL circuit 30 is phase-synchronized with the reference signals (VFO1 to VFO3) in the address part, and is further phase-synchronized with the clock component included in the ID signal (hereinafter precoded in this address part). The image is recorded in the data recording area (DATA-AREA) so as to generate a reproduction clock CK1 and to synchronize the phase with the reference signal (VFO4) in the subsequent user area. The recovered clock CK1 is generated so as to be phase-synchronized with the clock component of the data.
[0045]
On the other hand, the oscillation circuit 34 is formed of a crystal oscillation circuit. By dividing the output signal of the crystal oscillation circuit, a data clock CK2 having the same frequency as the reproduction clock CK1 is generated and output. In this case, the reproducing system is driven based on the reproducing clock CK1, whereas the recording system is driven based on the data clock CK2.
[0046]
That is, in the RF circuit 9, the reproduction signal processing circuit 35 binarizes the reproduction signal RF, and then sequentially latches the reproduction signal RF with reference to the reproduction clock CK1, thereby converting the reproduction signal RF into serial data. Further, the RF circuit 9 NRZI-demodulates this serial data with reference to the reproduction clock CK 1, and outputs the reproduction data obtained as a result to the error correction circuit 8. At this time, the reproduction signal processing circuit 35 detects the sector mark SM from the reproduction signal RF, thereby detecting the timing at which the laser beam starts scanning each sector, and outputs this timing detection result.
[0047]
The address detection circuit 36 detects the address data AD1 of each sector by processing the reproduction data output from the RF circuit 9 on the basis of the timing detection result, and this address data AD1 is detected by the system control circuit 25, It outputs to the timing generator (TG) 37.
[0048]
On the other hand, in the RF circuit 9, the recording data processing circuit 39 performs NRZI modulation on the encoded data output from the error correction circuit 8 on the basis of the clock CK2 output from the oscillation circuit 34, and is obtained as a result. The modulation signal is output to the laser power control circuit 10 with the timing signal output from the timing generator 37 as a reference.
[0049]
As a result, in the optical disc apparatus 1, in the reproduction mode, the reproduction clock synchronized with the precode signal and the clock component such as image data, respectively, during the period during which the laser beam scans the address portion of each sector and the recorded user area. Reproduction data is generated by CK1, and image data is reproduced from a desired sector with reference to address data AD1 detected from the reproduction data. On the other hand, in the recording mode, the reproduction data is processed by the reproduction clock CK1 to detect the address data AD1, thereby detecting the recording target sector and using the data clock CK2 output from the oscillation circuit 34 as a reference. The desired image data is recorded in the user area of the sector.
[0050]
As shown in FIG. 5, the no-signal detection circuit 40 monitors the signal level of the reproduction signal RF (FIG. 5A) processed by the reproduction signal processing circuit 35, and the signal level of the reproduction signal RF rises. During the falling period, the signal level detection result S1 (FIG. 5B) in which the signal level rises is output. Thereby, the no-signal detection circuit 40 is configured to detect a no-signal period in which the reproduction signal RF does not include the operation reference signal of the PLL circuit 30.
[0051]
The selection circuit 31 receives the signal level detection result S1 via the OR circuit 42, and outputs the data clock CK2 to the PLL circuit 30 instead of the reproduction signal RF during the period when the signal level of the signal level detection result S1 rises. To do. Accordingly, the selection circuit 31 supplies the data clock CK2 to the PLL circuit 30 instead of the reproduction signal RF during a non-signal period in which the reproduction signal RF does not include the operation reference signal of the PLL circuit 30 (FIG. 3 (C)).
[0052]
As a result, the PLL circuit 30 operates by forming a feedback loop so as to be phase-synchronized with the data clock CK2, and the stability can be improved by the amount of the loop gain. Therefore, the operation can be stabilized, and the fluctuation of the oscillation frequency can be effectively avoided by the noise component of the reproduction signal RF. Further, frequency fluctuation due to temperature noise can be effectively avoided. Therefore, the PLL circuit 30 can promptly synchronize the phase with the reference signal VFO1 of the sector that continues and the reference signal VFO4 of the user area, and the magneto-optical disk 2 can record this type of reference signal accordingly. The recording density can be improved by reducing the area.
[0053]
Incidentally, even when image data is recorded in the user area and the recorded image data is erased, the reproduction signal RF does not include an operation reference signal of the PLL circuit 30. However, in these cases, in the reproduction signal RF, recording signals for writing and erasing are mixed through the optical system, so that it may be difficult for the no-signal detection circuit 40 to detect this period.
[0054]
For this reason, in this embodiment, the data clock CK2 is supplied instead of the reproduction signal RF during these periods by switching the contact of the selection circuit 31 based on the timing signal output from the timing generator 37.
[0055]
That is, the timing generator 37 switches to the recording mode in response to the mode setting signal R / W output from the system control circuit 25. In this recording mode, the address data AD1 output from the address detection circuit 36 and the system control circuit 25, a sector to be recorded and erased is detected.
[0056]
Further, the timing generator 37 counts the clock CK2 output from the oscillation circuit 34 on the basis of the timing detection result of the sector mark SM output from the reproduction signal processing circuit 35. As a result, as shown in FIG. A timing signal S2 (FIG. 6B) at which the signal level rises is output to the recording data processing circuit 39 during the period in which the laser beam scans the user area of the sector to be erased. As a result, the recording data processing circuit 39 outputs a recording signal in the user area for recording with reference to the timing signal S2.
[0057]
Further, the timing generator 37 outputs the timing signal S2 to the OR circuit 42, thereby supplying the data clock CK2 to the PLL circuit 30 in place of the reproduction signal RF during the period during which the user area is recorded and erased (FIG. 6 (A) and (C)).
[0058]
As a result, the PLL circuit 30 can stabilize the operation and effectively avoid fluctuations in the oscillation frequency even during these recording and erasing operations, and can promptly synchronize the phase with the reference signal VFO1 of the subsequent sector.
[0059]
The system control circuit 25 is formed by a microcomputer that controls the overall operation of the optical disc apparatus 1 by executing a prescribed processing procedure, and controls the overall operation in response to a control command or the like input from an external device. To do. That is, the system control circuit 25 drives the radial servo circuit 19 and the like with reference to the address data AD1 output from the address detection circuit 36, and seeks the optical blocks 3 to 6 to a desired sector. The sequentially input image data is recorded, and the image data is reproduced and output from these sectors.
[0060]
In these processes, the system control circuit 25 outputs the above-described mode setting signal R / W to the timing generator 37 and also outputs the same mode setting signal to the error correction circuit 8, the RF circuit 9 and the like. Control the behavior. Further, when the adjustment mode is set from the external device, the system control circuit 25 outputs a switching signal S3 to the OR circuit 42, thereby forcibly switching the input signal of the PLL circuit 30 to the data clock CK2.
[0061]
As a result, the optical disk apparatus 1 is formed so that the oscillation frequency of the oscillation circuit 34 can be adjusted and confirmed as necessary, and the operation of the PLL circuit 9 and the like can be confirmed.
[0062]
(2) Operation of the embodiment
In the above configuration, the laser beams L (FIG. 2) emitted from the optical blocks 3 to 6 are collected on the information recording surface of the magneto-optical disk 2 and the return light is received by the light receiving systems of the optical blocks 3 to 6, respectively. A reproduction signal RF that is received and whose signal level changes according to the change in the polarization plane of the return light is generated.
[0063]
The reproduction signal RF is amplified by a preamplifier 17 with a specified gain, and then input to the RF circuit 9. In the reproduction signal processing circuit 35 (FIG. 1) of the RF circuit 9, the reproduction signal RF is precoded at the head of each sector. The recorded sector mark SM is detected, whereby the timing at which the laser beam starts scanning each sector is detected.
[0064]
Further, the reproduction signal RF is subsequently binarized and then latched with reference to the reproduction clock CK1 output from the PLL circuit 30, converted into serial data, and this serial data is NRZI demodulated into reproduction data. Converted. As for this reproduction data, an ID signal is detected in the subsequent address detection circuit 36 with reference to the timing of the sector mark SM detected in the reproduction signal processing circuit 35 (FIG. 2), and each laser beam irradiation position is determined from this ID signal. Sector address data AD1 is detected.
[0065]
As a result, the reproduced data is decoded by the subsequent error correction circuit 8, subjected to error correction processing, converted into image data, and an image designated by the external device from among these image data with reference to the address data AD 1. Data is sent to the external device.
[0066]
In this process, the signal level of the reproduction signal RF is detected by the no-signal detection circuit 40, and thereby a no-signal period in which the reproduction signal RF does not include the operation reference signal of the PLL circuit 30 is detected.
[0067]
This detection result S1 is supplied to the selection circuit 31 via the OR circuit 42, whereby the input signal of the PLL circuit 30 is changed between the reproduction signal RF and the data clock CK2 in accordance with the detection result of the no-signal detection circuit 40. Switch with. That is, the reproduction signal RF is in a period in which the reproduction signal RF includes an operation reference signal of the PLL circuit 30 in the reproduction mode, that is, a period in which the laser beam L scans the address portion to obtain a precode signal. During this period and during a period during which the laser beam L scans the recorded user area, the laser beam L is input to the PLL circuit 30 via the selection circuit 31.
[0068]
Thus, during these periods, the reproduction signal RF is phase-compared with the reproduction clock CK1 output from the voltage-controlled oscillation circuit 33, and the phase comparison result is supplied to the voltage-controlled oscillation circuit 33 as an error voltage. A reproduction clock that is phase-synchronized with the precode signal is generated.
[0069]
As a result, the reproduction clock CK1 is used as the operation reference clock in the reproduction signal processing circuit 35 and the error correction circuit 8, and the image data recorded on the magneto-optical disk 2 can be reproduced.
[0070]
On the other hand, during the period in which the reproduction signal RF does not include the operation reference signal of the PLL circuit 30, the data clock CK2 is supplied to the PLL circuit 30, so that the data clock CK2 is used as the operation reference. It operates stably and frequency fluctuations due to noise are effectively avoided.
[0071]
On the other hand, at the time of recording and erasing, the timing generator 37 compares the address data AD1 detected by the address detection circuit 36 with the address data AD2 output from the system control circuit 25. A sector for recording and erasing purposes is detected. Further, based on the timing of the sector mark SM detected by the reproduction signal processing circuit 35, the timing generator 37 generates a timing signal S2 whose signal level rises in the user area of the sector for recording and erasing.
[0072]
Among these, during recording, image data input from an external device is encoded after an error correction code is added by an error correction circuit 8 operated by a clock CK2, and the resulting encoded data is recorded data. The signal is converted into a recording signal by the processing circuit 39 and output to the laser power control circuit 10 with reference to the timing signal S2. As a result, in the unrecorded user area, the light quantity of the laser beam L rises intermittently according to the image data, and the image data is recorded in these areas.
[0073]
At the time of erasure, the laser beam L is irradiated with a prescribed write light amount in the recorded user area with reference to the timing signal S2, and the image data recorded in the user area is erased.
[0074]
At the time of recording / erasing, the timing signal S2 is supplied to the selection circuit 31 together with the signal level detection result S1 via the OR circuit 42, whereby the input signal of the PLL circuit 30 is switched between the reproduction signal RF and the data clock CK2. Even when the signal level of the reproduction signal RF rises, the reproduction signal RF is detected by the recording signal mixed during the period when the laser beam scans the user area to be erased and recorded, that is, through the optical system. Even during the period in which the signal level rises, the data clock CK2 is supplied to the PLL circuit 30 instead of the reproduction signal RF.
[0075]
As a result, in addition to the gap between sectors and the gap between the address portion and the user area, the data clock CK2 is supplied to the PLL circuit 30 while the laser beam is scanning the user area to be erased and recorded. The PLL circuit 30 operates stably during these periods, and frequency fluctuations due to noise are effectively avoided.
[0076]
On the other hand, when the adjustment mode is set, the switching signal S3 output from the system control circuit 25 is supplied to the selection circuit 31 via the OR circuit 42, and the data clock CK2 is forcibly supplied to the PLL circuit 30. Thus, various operations are checked and adjusted.
[0077]
(3) Effects of the embodiment
According to the above configuration, during the period in which the reproduction signal RF does not include the operation reference signal of the PLL circuit 30, and at the time of recording / erasing, in addition to this, the user area to be written and the erase target user area are set to the laser beam. By supplying the data clock CK2 which is the operation reference of the recording system instead of the reproduction signal RF during the scanning period, the operation of the PLL circuit 30 can be stabilized during these periods, and the frequency fluctuation Can be reduced. Accordingly, it is possible to shorten the lead-in time by the subsequent pre-code signal, and accordingly, the recording area of the reference signal can be set small to improve the recording density of the magneto-optical disk 2.
[0078]
(4) Other embodiments
In the above-described embodiment, the case where the period during which the laser beam scans the user area to be erased and recorded on the basis of the sector mark detection timing has been described. However, the present invention is not limited to this. The period during which the laser beam scans the user area to be erased and recorded on the basis of the preamble or the like may be detected.
[0079]
Further, in the above-described embodiment, the case where the information recording surface is divided into the two areas of the inner peripheral side and the outer peripheral side has been described. Furthermore, the present invention can be widely applied when the information recording surface is not divided as described above.
[0080]
Further, in the above-described embodiments, the case where the magneto-optical disk is rotationally driven under the condition of constant angular velocity has been described. However, the present invention is not limited to this, and the magneto-optical disk is also rotationally driven under the condition of constant linear velocity. Can be widely applied.
[0081]
Further, in the above-described embodiments, the case where image data is recorded / reproduced has been described. However, the present invention is not limited to this, and the present invention is widely applied to an optical disk apparatus for recording / reproducing various data, and further to an optical disk apparatus dedicated to recording. Can do.
[0082]
Further, in the above-described embodiment, the case where the data clock CK2 serving as the recording operation reference is supplied instead of the reproduction signal RF has been described. However, the present invention is not limited to this, and a case where a dedicated reference signal is supplied, etc. Can be widely applied.
[0083]
In the above-described embodiment, the case where the present invention is applied to an optical disk apparatus that records and reproduces image data on a magneto-optical disk has been described. However, the present invention is not limited to this, and the write-once optical disk apparatus and further the optical disk The present invention is not limited to the apparatus, and can be widely applied to disk apparatuses that record desired data on various disk-shaped recording media such as magnetic recording / reproducing apparatuses.
[0084]
【The invention's effect】
As described above, according to the present invention, during the period in which the recovered clock cannot be generated correctly, the specified drive signal is supplied to the PLL circuit that generates the recovered clock, thereby stabilizing the operation of the PLL circuit and reducing the pull-in time. It can be shortened.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a signal processing system of an optical disc apparatus according to an embodiment of the present invention.
2 is a block diagram showing the overall configuration of the optical disc apparatus of FIG. 1. FIG.
3 is a front view showing a magneto-optical disk applied to the optical disk apparatus of FIG. 2. FIG.
4 is a chart showing a sector format of a magneto-optical disk applied to the optical disk apparatus of FIG. 2;
FIG. 5 is a signal waveform diagram for explaining the operation of the PLL circuit during reproduction;
FIG. 6 is a signal waveform diagram for explaining the operation of the PLL circuit during recording / erasing.
[Explanation of symbols]
1 Optical disk device
2 Magneto-optical disk
3-6 optical block
9 RF circuit
25 System control circuit
30 PLL circuit
31 Selection circuit
33 Address detection circuit
37 Timing Generator
42 OR circuit

Claims (1)

A reproduction signal obtained from a disk-shaped recording medium is supplied to a PLL circuit, a clock is generated by the PLL circuit based on a precode signal recorded intermittently on the disk-shaped recording medium, and the clock is used as a reference. In a disk device that detects position information of the disk-shaped recording medium and records desired data based on the detection result,
Monitoring the signal level of the reproduced signal obtained from said disc-shaped recording medium, it detects the signal level falls period of the reproduced signal, during the period of the no-signal can not be obtained reproduced signal of the pre-code signal, the signal A no-signal detection circuit that outputs a detection signal whose level rises;
Detects the precode signal, generates and outputs a specified drive signal based on the detection timing, and outputs a signal level during a period of recording and erasing the user area of the disc-shaped recording medium A timing generator that outputs a timing signal
An OR circuit to which the detection signal and the timing signal are supplied;
A period of time during which the signal level of the output signal of the OR circuit rises by selecting a reproduction signal that is controlled by the output signal of the OR circuit and that is obtained from the disc-shaped recording medium and a specified drive signal generated by the timing generator . A disk device comprising a selection circuit for supplying the prescribed drive signal to the PLL circuit instead of the reproduction signal.

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