JP2000067434A - Phase comparison device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase comparison device capable of accurately detecting a variation amount with respect to the original phase of an extracted wobble signal caused by influence of cross-talk from adjoining groove tracks. SOLUTION: The phase comparison device PD comparing prepits with a wobbling signal of an information recording device S with respect to an optical disk which has grove tracks wobbled by a wobble signal and land tracks as guide tracks to guide a recording beam, and has prepits formed on the land tracks with a specified phase relation to the wobbling signal but not formed on the land tracks adjacent to a same straight line in the direction of the radius, is provided with a wobble signal extracting means 15 for extracting the wobble signal, a prepit detecting means 13, a periodic signal generating means for generating a periodic signal synchronizing with the extracted wobble signal and monotonously increasing for a periodic period corresponding to a specified frequency, and a holding means for latching the amplitude level of the periodic signal at the timing of detecting the prepits.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording apparatus for recording information on a recordable optical disk based on a recording clock signal synchronized with the rotation of the optical disk. The present invention relates to a phase comparison device used in a clock signal generator.

[0002]

2. Description of the Related Art A CD-R (Compact Disc-Recordable) is known as a write-once optical disc which can be recorded only once.

A CD-R has a predetermined frequency (22.05 KH) based on pre-information such as track position information on a disk.
There is a groove track (information recording track) slightly wobbled (wobbled) in the radial direction of the disc in accordance with the wobble signal obtained by FM-modulating the carrier having z).

In order to extract a wobble signal from such a groove track, the reflected light of the irradiated light beam from the groove track is received by a photodetector divided into two by a division line optically parallel to the tangential direction of the groove track. The difference between the outputs from the detectors is calculated, and the difference signal is converted to a BPF (Ba
nd Pass Filter).

[0005] The rotation of the CD-R is controlled so that the average frequency of the wobble signal extracted via the BPF becomes the above-mentioned predetermined frequency. At this time, the extracted wobble signal (hereinafter, referred to as an extracted wobble signal) is also used as a reference signal for generating a recording clock signal. That is, the extracted wobble signal is a continuous signal having a frequency component synchronized with the rotation of the disk, and by generating a clock signal that is phase-synchronized with the continuous signal, a recording clock signal accurately synchronized with the rotation of the disk Is generated.

[0006]

Recently, a so-called DVD-R (Digital Versatil) has been used as an information recording medium whose recording capacity has been improved about seven times as much as that of a conventional CD-R.
e Disc-Recordable) has been actively researched and developed.

In a DVD-R, the pitch between adjacent tracks is set to be approximately half that of a CD-R in order to perform high-density recording. Therefore, leakage from a groove track adjacent to the groove track irradiated with the light beam, that is, crosstalk cannot be ignored. If there is crosstalk from adjacent left and right groove tracks, the extracted wobble signal will be interfered by the wobble signal component of the adjacent groove track, and its amplitude and phase will fluctuate. In particular, there is a problem that a clock signal accurately synchronized with the rotation of the disk cannot be generated from the extracted wobble signal affected by the crosstalk due to phase fluctuation, that is, accompanying jitter.

That is, when a rotation control signal (a phase difference between the reference signal and the extracted wobble signal) fluctuates due to crosstalk or the like, the time required for the rotation control to be established in response to the rotation control signal is reduced. Is different from the time required until the PLL circuit for generating the clock signal is established (usually, the response of the rotation control is PL due to the inertia of the disk.
(The response is much slower than the response of the L circuit.) Therefore, the phase of the clock signal and the rotation phase of the disk are shifted between them. When such a shift occurs, it becomes impossible to record and form a data pattern to be recorded at a position where recording is to be performed.

Therefore, the clock signal generator detects the amount of change between the phase of the extracted wobble signal and the phase inherent in the wobble signal, and cancels the amount of change with respect to the generated recording clock signal. It is desired to configure, but for that, a phase comparison device capable of accurately detecting the above-mentioned fluctuation amount is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to accurately detect a fluctuation amount of an extracted wobble signal from an inherent phase due to the influence of crosstalk from an adjacent groove track. It is an object of the present invention to provide a phase comparison device capable of performing the following.

[0011]

According to a first aspect of the present invention, there is provided a phase comparison apparatus comprising: an information recording track wobbled by a wobble signal having a predetermined frequency; And a guide track for guiding a recording beam to the wobble signal. The guide track is formed on the guide track with a predetermined phase relationship with respect to the wobble signal, and on a guide track adjacent on the same straight line in the radial direction. Is a phase comparison device that compares the phase of the wobble signal and the prepit in an information recording device that records information on an optical disk having prepits that are not formed, and a wobble signal extraction unit that extracts the wobble signal; Pre-pit detecting means for detecting the pre-pit, and in synchronization with the extracted wobble signal, A periodic signal generating unit that generates a periodic signal that monotonically increases during a period corresponding to the predetermined frequency; and a holding unit that latches the amplitude level of the periodic signal at the pre-pit detection timing. You.

According to a second aspect of the present invention, in the phase comparison device according to the first aspect, the holding means further includes an averaging means for averaging the latched amplitude level,
The output of the averaging means is held.

According to the phase comparison device of the present invention,
An information recording track wobbled with a wobble signal having a predetermined frequency, and a guide track for guiding a recording beam to the information recording track; and a predetermined phase on the guide track with respect to the wobble signal. The wobble signal extracted from the wobble signal and the pre-pits are detected when detecting the rotation phase of the disc when information is recorded on the optical disc having pre-pits that are formed on the same straight line in the disc radial direction and are not formed on adjacent guide tracks. Are compared with each other.

Here, the pre-pit signal is recorded with a predetermined phase relationship with the wobble signal. Further, since the pre-pit signal does not exist at adjacent land track positions on the same straight line in the disk radial direction, such a pre-pit signal is detected without being affected by crosstalk.

Therefore, even when the time axis of the extracted wobble signal in a desired groove track fluctuates due to the crosstalk caused by the wobble signal of the adjacent groove track, the phase of the extracted wobble signal is compared with the phase of the prepit detection signal. Thus, the amount of fluctuation of the extracted wobble signal with respect to the inherent phase can be accurately detected, and a recording clock signal accurately synchronized with the rotation of the disk can be generated.

Even if the detection of the pre-pit signal is erroneous due to the influence of noise or the like, the phase of the extracted wobble signal extracted from the groove track is compared with the phase of the pre-pit detection signal to generate a phase adjustment signal. So do
The effect of erroneous detection of the pre-pit signal is reduced, and accurate phase comparison can be performed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described with reference to the drawings. First, a DVD-R as an optical disk in which prepits corresponding to preinformation are formed and groove tracks to be described later are wobbled at a predetermined frequency will be described with reference to FIGS.

First, the structure of a DVD-R will be described with reference to FIG. In FIG. 1, a DVD-R 31 is a dye-type DVD-R having a dye film 35 as a data recording layer and capable of writing information data only once, and includes a groove track 32 as an information recording track and the groove track 32. A land track 33 is formed as a guide track for guiding a light beam B such as a laser beam as a reproduction light or a recording light. Further, a protective film 37 for protecting them and a gold vapor-deposited film 36 for reflecting the light beam B when reproducing recorded data are provided. The land track 33 has pre-pits 34 corresponding to the pre-information. The pre-pits 34 are formed before shipping the DVD-R 31.

Further, in the DVD-R 31, the groove track 32 is wobbled at a frequency corresponding to the rotation speed of the disk. The wobbled groove track 32 is formed in advance before the DVD-R 31 is shipped, like the pre-pit 34.

When recording information data (information information other than the pre-information, such as image information to be originally recorded, the same applies hereinafter) is recorded on the DVD-R 31, this groove track is recorded in an information recording apparatus described later. The DVD-R 31 is controlled to rotate at a predetermined rotation speed by extracting a wobbling frequency of 32, and pre-information is obtained in advance by detecting a pre-pit 34, and based on the pre-information, an optimal output of a light beam B as a recording light is obtained. Are set, and the recording information data is recorded on the DVD-R 31.
Address information or the like indicating the upper position is obtained, and recording information data is recorded at the corresponding recording position based on the address information.

At the time of recording the recording information data, the light beam B is irradiated so that the center thereof coincides with the center of the groove track 32 to form recording information pits corresponding to the recording information data on the groove track 32. Thereby, the record information data is recorded. At this time, the light spot S
The size of P is set so that a part thereof is irradiated not only on the groove track 32 but also on the land track 33 as shown in FIG.

The push-pull method (the tangential direction of the groove track 32, ie, D
A push-pull method (hereinafter, referred to as a radial push-pull method) using a photodetector divided by a dividing line parallel to the rotation direction of the VD-R 31 detects pre-information from the pre-pits 34 and stores the pre-information. At the same time, a wobble signal is extracted from the groove track 32, and a recording clock signal to be described later, which is synchronized with the rotation of the disk, is obtained.

Next, the recording format of the pre-information pre-recorded on the DVD-R 31 will be described with reference to FIG. In FIG. 2, the upper row shows the recording format of the recording information data, and the lower waveform shows the wobbling state of the groove track 32 (the plan view of the groove track 32) for recording the recording information data. The upward arrow during the wobbling state of the track 32 schematically indicates the position where the prepit 34 is formed. Here, in FIG. 2, the wobbling state of the groove track 32 is as follows.
For the sake of easy understanding, an amplitude larger than the actual amplitude is used. The recording information data is recorded on the center line of the groove track 32.

As shown in FIG. 2, the record information data recorded on the DVD-R 31 is divided in advance into sync frames as information units. One recording sector is formed by 26 sync frames, and one EC is formed by 16 recording sectors.
An error correcting code (C) block is formed.
One sync frame has a unit length (hereinafter, referred to as T) 1488 corresponding to a pit interval defined by a recording format when recording the recording information data.
It has a length of double (1488T), and the part of the length of 32T at the beginning of one sync frame is used as synchronization information SY for synchronizing each sync frame.

On the other hand, the pre-information recorded on the DVD-R 31 is recorded for each sync frame. Here, when the pre-information is recorded on the DVD-R 31 by the pre-pits 34, the synchronization signal in the pre-information is placed on the land track 33 adjacent to the area where the synchronization information SY in each sync frame in the recording information is recorded. As shown, one pre-pit 34 is always formed,
On the land track 33 adjacent to the first half of the sync frame other than the synchronization information SY, two or one pre-pits 34 are used to indicate the contents of the pre-information to be recorded.
(Note that the pre-pit 34 may not be formed in the first half of the sync frame other than the synchronization information SY depending on the content of the pre-information to be recorded.)

At this time, in one recording sector, pre-pits 34 are formed only in even-numbered sync frames (hereinafter referred to as EVEN frames), and pre-information is recorded. That is, in FIG.
When the pre-pits 34 are formed in the frame (FIG. 2
Is indicated by a solid line upward arrow. ), O next to it
The pre-pit 34 is not formed in the DD frame. The relationship between the presence or absence of each of the pre-pits 34 (pre-pits B2, B1, and B0 from the beginning of the sync frame, respectively) in one EVEN frame and the subsequent ODD frame is determined by whether the one EVEN frame is the beginning of a recording sector. No, and it is set in accordance with the content of information to be recorded in the one EVEN frame and the subsequent ODD frame.

More specifically, when pre-pits are formed in the EVEN frame, all pre-pits 34 are formed in the first sync frame of the recording sector.
(Pre-pits B2, B1 and B0) are formed,
In the sync frame other than the head of the recording sector, the pre-pits B2 and B0 are formed when the pre-information to be recorded in the sync frame is "1", and when the pre-information to be recorded is "0", only the pre-pit B2 is formed. It is formed. When a pre-pit is formed in the ODD frame, the pre-pits B2 and B2
1 is formed, and the sync frames other than the head of the recording sector are the same as in the case of the EVEN frame.

The pre-pit 34 to be formed in the sync frame of the EVEN frame or the ODD frame is determined depending on the position of the pre-pit 34 previously formed on the adjacent land track. That is, the pre-pits 34 are usually formed in the EVEN frame. However, when the pre-pits 34 are formed in the EVEN frame, the pre-pits 34 on the adjacent land tracks formed in advance and the radial direction of the DVD-R31 disk are formed. When approaching, the pre-pit 34 is formed in the ODD frame. By forming in this manner, the pre-pit 3 is located at the adjacent land track position.
4 is no longer present, so that the influence of crosstalk can be reduced when detecting the pre-pits 34.

On the other hand, the groove track 32 is wobbled at a constant wobbling frequency f0 of 140 KHz (frequency at which eight wobble signals are included in one sync frame) over all sync frames. Then, in the information recording apparatus described later, by extracting the constant wobbling frequency f0, a signal for controlling the rotation of the spindle motor is detected and a recording clock signal is generated.

In order to keep the phase relationship between the pre-pit 34 and the wobble signal constant, the pre-pit B2 is formed at a predetermined position (for example, a position separated by 7T) from the start position of the sync frame, and 186T (from the pre-pit B2). 1
488T / 8), and the pre-pits B1 and B0 are formed at intervals of about 488 T / 8.
No. 3,109,941. ).

[0031]First embodiment of phase comparison device  Next, the phase comparison according to the present invention included in the information recording device
A first embodiment of the device will be described with reference to FIGS.
Will be described. In the following description, the host computer
The recording information data transmitted from the
Information recording device for recording on R31
An embodiment to which the invention is applied will be described.

First, the overall configuration and operation of the information recording apparatus including the phase comparison apparatus according to this embodiment will be described with reference to FIG. In the following embodiment, a DVD
In the R-R31, the pre-pits 34 including the address information and the like on the DVD-R 31 and the groove track 32 to be wobbled are formed in advance, and when the recording information data is recorded, the pre-pits 34 are detected in advance so that the DVD-R 31 is detected. The above address information is obtained, and the recording position on the DVD-R 31 where the recording information data is to be recorded is detected and recorded.

As shown in FIG. 3, the information recording apparatus S includes a pickup 1, a spindle motor 2, a spindle driver 3, a laser drive circuit 4, and a power control circuit 5.
, An encoder 6, a reproduction amplifier 8, a decoder 9,
A processor (CPU) 10, a reference clock generator 11 for generating a reference clock signal for rotation control,
F (Band Pass Filter) 12, a pre-pit signal detector 13 as pre-pit detection means, a pre-pit signal decoder 14, a wobble signal extractor 15 and a phase comparator 16 as wobble signal extraction means, and a rotation control signal are generated. Phase comparator 17, phase comparator 181, LPF
(Low Pass Filter) 182, VCO (Voltage Controll)
ed Oscillator) 183 PLL (Phase Locked)
(Loop) circuit 18 and a phase shifter 19.

Of these, the BPF 12, the pre-pit signal detector 13, the wobble signal extractor 15, the phase comparator 1
6 constitutes the phase comparison device PD in the present invention. Further, a PLL circuit 18 and a phase shifter 19 are added to constitute a recording clock signal generator G. In addition, the information recording device can receive data from an external host computer (not shown).
Information data to be recorded is input via the interface 7.

Next, the overall operation will be described. The pickup 1 includes a laser diode (not shown), a polarizing beam splitter, an objective lens, a photodetector, and the like. In a recording operation, the pickup 1 responds to a laser drive signal based on recording information data supplied from a laser drive circuit 4. The recording beam data is recorded by irradiating the information recording surface of the DVD-R 31 with the light beam B at the changing output power, and the light beam B is applied at a constant output power (read power) during the reading operation.
It operates so as to irradiate the VD-R31 and receive the reflected light with the photodetector.

The pickup 1 receives the reflected light of the light beam irradiated on the information recording surface from the information recording surface by a photodetector, converts the light into an electric signal, and performs an operation based on, for example, a radial push-pull method. By performing the processing, a wobble signal of the pre-pits 34 and the groove track 32 and a detection signal SDT carrying recording information data and the like are generated, and output to the reproduction amplifier 8.

The reproduction amplifier 8 amplifies the pre-pit signal of the pre-pit 34 and the detection signal SDT carrying the wobble signal of the groove track 32 output from the pickup 1, and the pre-amplifier includes the pre-pit signal of the pre-pit 34 and the wobble signal of the groove track 32. The information signal Spp is output to the BPF 12 of the recording clock signal generator G, and at the time of a reading operation, the amplified signal Sp corresponding to the recorded information data already recorded is output to the decoder 9.

The decoder 9 performs 8/16 demodulation and deinterleaving on the input amplified signal Sp to decode the amplified signal Sp to generate a demodulated signal SDM, and outputs the demodulated signal SDM to the CPU 10. I do.

On the other hand, the BPF 12 removes a noise component included in the pre-information signal Spp supplied from the reproduction amplifier 8, and superimposes the pre-pit signal at a predetermined position (for example, a maximum amplitude position) of the wobble signal, and the composite signal Spc ( FIG.
(A)) is output to the pre-pit signal detector 13 and the wobble signal extractor 15.

A pre-pit signal detector 13 serving as pre-pit signal detection means compares a composite signal Spc with a predetermined reference value, for example, a level Vrp which is larger than the maximum amplitude value of the wobble signal in FIG. During the period when the amplitude level of the composite signal Spc is larger than the reference value Vrp, that is, during the period when the pre-pit exists, the pre-pit detection signal SPD which is a pulse signal is output to the pre-pit signal decoder 14 and the phase comparator 16. .

The pre-pit signal decoder 14 decodes pre-information including address information on the DVD-R 31 from the supplied pre-pit detection signal SPD and outputs it to the CPU 10.

On the other hand, the wobble signal extractor 15 as the wobble signal extraction means converts the composite signal Spc to a predetermined reference value, for example, the PP (Peak to Pe) of the wobble signal in FIG.
ak) A comparator (not shown) for comparing the value with the intermediate level Vr0 of the value is provided.
The pulse signal (FIG. 5 (b)) which is at the H (High) level during a period longer than r0 is used as the extracted wobble signal SWB for the phase comparators 16 and 17 and the PLL circuit 18 which is the recording clock signal generating means. Output.

The PLL circuit 18 includes a phase comparator 181, L
The phase shifter 19 includes a PF 182, a VCO 183, and a frequency divider 184, and outputs a clock signal SCK synchronized with the phase of the input extracted wobble signal SWB to the phase shifter 19.

On the other hand, the phase comparator 16 generates the pre-pit detection signal SPD and the extracted wobble signal SWB by the operation described later.
And a phase adjustment signal SCNT indicating a deviation from a predetermined phase relationship between the pre-pit detection signal SPD and the extracted wobble signal SWB, that is, a variation amount of the extracted wobble signal SWB with respect to a phase which should be originally possessed. Table 19
Output to

The phase shifter 19 adjusts the phase of the clock signal SCK supplied from the PLL circuit 18 based on the phase adjustment signal SCNT by a method described later, and the encoder 6 and the power control circuit as the recording clock signal SCR. 5 is output.

On the other hand, the phase comparator 17 compares the phase of the input extracted wobble signal SWB with the reference clock signal SREF supplied from the reference clock generator 11 and carrying the reference frequency component of the rotation speed of the DVD-R 31. The difference signal is supplied to the spindle motor 2 via the spindle driver 3 as a rotation control signal. Thus, a spindle servo is configured, and the DVD-R 31 is rotated at a predetermined rotation speed.

On the other hand, under the control of the CPU 10, the interface 7 performs an interface operation on the recording information data SRR transmitted from a host computer (not shown) so as to capture the recording information data SRR into the information recording apparatus. To the encoder 6.

The encoder 6 uses the recording clock signal SCR supplied from the phase shifter 19 as a timing signal,
It performs CC processing, 8/16 modulation processing, and scramble processing, generates a modulation signal SRE, and outputs it to the power control circuit 5.

The power control circuit 5 converts the waveform of the modulation signal SRE based on the recording clock signal SCR output from the clock signal generator G in order to improve the shape of the recording pits formed on the disk. A so-called write strategy process) is performed, and is output to the laser drive circuit 4 as a recording signal SD.

The laser drive circuit 4 actually drives a laser diode (not shown) in the pickup 1 and emits a light beam B with an output power corresponding to the supplied recording signal SD.
And outputs a laser drive signal for emitting the laser beam.

At the time of the recording operation, the CPU 10 obtains address information from the pre-information supplied from the pre-pit signal decoder 14, and obtains a DVD-ROM corresponding to the address information.
The entire information recording apparatus is controlled so that the recording information data is recorded at a position on R31. In the case of the reproducing operation, the CPU 1
Numeral 0 controls the entire information recording apparatus so as to acquire the recording information data recorded on the disk 31 from the demodulated signal SDM and output the recording information data to an external host computer.

Next, more specific configurations of the phase comparator 16 and the phase shifter 19 according to the present invention will be described with reference to FIGS.

The phase comparator 16 outputs the extracted wobble signal SWB
Triangular wave generating circuit 163 as a periodic signal generating means for generating a triangular wave signal having a predetermined inclination angle during the H level of
And a sample and hold circuit 164 as holding means for holding the amplitude level of the generated triangular wave signal at the detection timing of the pre-pit detection signal SPD.

The triangular wave generating circuit 163 includes a capacitor 45 having one end grounded, a constant current source 46 connected to the other end of the capacitor 45 to supply a constant current to the capacitor 45, and a grounded one end and the other end. Comprises a switch 47 connected to a connection point a between the capacitor 45 and the constant current source 46. The switch 47 is
Extracted wobble signal S supplied via buffer 161
In response to the WB, the extracted wobble signal SWB is kept open while the extracted wobble signal SWB is at the H level, and
The period of the (Low) level is closed.

With the above configuration, a triangular wave signal is generated. That is, when the extracted wobble signal SWB becomes H level and the switch 47 is opened, the constant current source 46
, The terminal voltage at the connection point a, that is, the charging voltage of the capacitor 45 increases at an inclination angle corresponding to the capacitance of the capacitor 45 (T1 in FIG. 5D). ).

On the other hand, when the extracted wobble signal SWB becomes L level and the switch 47 is closed, the capacitor 4
The charging voltage of 5 is discharged at a stretch via the switch 47,
The connection point a becomes the ground voltage (T2 in FIG. 5D). During this time, the charging current supplied from the constant current source 46 is also switched
7, the capacitor 45 is bypassed. And
When the switch 47 is opened again, the capacitor 45
The supply of the charging current to the capacitor 45 is restarted, and the terminal voltage of the capacitor 45 rises with a constant slope from the ground voltage with time (T3 in FIG. 5D). Thus, the triangular wave generation circuit 1
63 generates a triangular wave signal whose amplitude level changes at a constant rate during the H level of the extracted wobble signal SWB, and outputs the triangular wave signal to the sample and hold circuit 164 via the buffer 162.

The sample-and-hold circuit 164 switches the triangular wave signal supplied via the buffer 162 to the capacitor 49 in accordance with the pre-pit detection signal SPD.
8 and a capacitor 49 for holding the voltage level of the relayed triangular wave signal.

The switch 48 receives the pre-pit detection signal SPD
Is closed during the H level, and supplies the triangular wave signal to the capacitor 49, while the prepit detection signal SPD is at the L level, and the supply of the triangular wave signal to the capacitor 49 is cut off.

Therefore, the capacitor 49 holds the charging voltage corresponding to the amplitude level of the triangular wave signal supplied during the high level period of the prepit detection signal SPD until the next high level period of the prepit detection signal SPD arrives. Will do. The charging voltage held by the capacitor 49 is supplied to the phase shifter 19 via the buffer 165 as the phase adjustment signal SCNT.

As described above, the phase comparator 16 generates a triangular wave signal having a predetermined inclination angle by charging and discharging the capacitor 45 according to the transition state between the H level / L level of the extracted wobble signal SWB. Then, the amplitude level of the triangular wave signal is sampled / held at the detection timing of the pre-pit detection signal SPD.

In the DVD-R31, the groove that carries the wobble signal and the prepit that carries the prepit signal are recorded with a predetermined phase relationship as shown in FIG.
Therefore, if the phase of the extracted wobble signal SWB output from the wobble signal extractor 15 and the phase of the prepit detection signal SPD output from the prepit signal detector 13 have the predetermined phase relationship, the signal level sampled / held is Are always at a predetermined voltage level (for example, FIG.
(It becomes the intermediate amplitude level VM of the triangular wave signal in (d)).

However, if a wobble signal component leaks from an adjacent groove track due to the influence of crosstalk, interference with the wobble signal component causes the extracted wobble signal SWB from the groove track to appear on the time axis. Will occur. on the other hand,
As described above, since the pre-pit signal is not formed close to the radial direction of the DVD-R 31, it is not affected by the crosstalk from the adjacent land track.
The pre-pit detection signal SPD detected from the composite signal SPC can be regarded as an accurate timing signal without fluctuation on the time axis based on crosstalk.

Therefore, the pre-pit detection signal S
By sampling / holding the triangular wave signal generated from the extracted wobble signal SWB by the PD, it is possible to know the amount of deviation from the above-described predetermined phase relationship, that is, the amount of change from the original phase of the wobble signal. In other words, the phase comparator 16 outputs a voltage signal (in this example, centered on the intermediate amplitude level VM) corresponding to the phase difference between the extracted wobble signal SWB and the pre-pit detection signal SPD (the time axis error of the extracted wobble signal caused by crosstalk). ). The phase difference signal is supplied to the phase shifter 19 as the phase adjustment signal SCNT.

On the other hand, the phase shifter 19 has a transistor 191 in which the clock signal SCK output from the PLL circuit 18 is supplied to the base terminal B via the capacitor 195, and an anode connected to the collector terminal C of the transistor 191. A variable capacitance diode 192 having a cathode connected to a resistor 193 at a connection point b via a capacitor 196, and one end connected to the emitter terminal E of the transistor 191 and the other end connected to a connection point b. And a resistor 193.

The phase adjustment signal SCNT supplied from the phase comparator 16 is connected to the cathode of the variable capacitance diode 192 via the resistor 194. Then, the recording clock signal SCR is output from the connection point b via the buffer 198. Note that a plurality of resistors 1
97 is a bias resistor of the transistor 191.

With the above configuration, the clock signal SCK supplied from the PLL circuit 18 is input to the phase shifter 19,
The phase of the clock signal SCK is shifted according to the phase adjustment signal SCNT supplied from the sample hold circuit 164. That is, the base terminal B of the transistor 191
Is output from the collector terminal C as an inverted signal whose phase is inverted by 180 degrees with respect to the input clock signal SCK, and is output from the emitter terminal E as an in-phase signal with the input clock signal. You. At this time, the variable capacitance diode 192 and the capacitor 19
6, the reactance value based on the capacitance is sufficiently smaller than the resistance value of the resistor 193, the output signal from the connection point b,
That is, the recording clock signal SCR output from the phase shifter 19 is shifted by approximately 180 degrees with respect to the input clock signal SCK.

On the other hand, if the reactance value is sufficiently larger than the resistance value, the input clock signal SCK and the recording clock signal SCR remain in phase. As described above, the amount of phase shift changes according to the impedance of the variable capacitance diode 192, the capacitor 196, and the resistor 193. In addition,
When a phase shift amount of 180 degrees or more is required, the phase shifter 1
9 may be connected in cascade to form a multistage configuration.

In this embodiment, the phase difference signal output from the phase comparator 16 is supplied to the variable capacitance diode 192 as the phase adjustment signal SCNT.
By changing the terminal voltage of the variable capacitance diode 192 by T, the reactance value of the variable capacitance diode is changed, and the phase shift amount of the clock signal SCK is changed to obtain the recording clock signal SCR. That is, the amount of the deviation is offset in accordance with how much the signal level of the phase adjustment signal SCNT deviates from the VM indicating that the phase relationship between the extracted wobble signal and the pre-pit detection signal is a predetermined phase relationship. Clock signal SCK
And outputs the adjusted clock signal to the encoder 6 and the power control circuit 5 as a recording clock signal.

As described above, the fluctuation on the time axis of the clock signal generated based on the wobble signal in which the influence of the crosstalk cannot be ignored is corrected by using the prepits which are not affected by the crosstalk. It is possible to generate a recording clock signal synchronized with high accuracy.

[0070]Second embodiment of phase comparison device  Next, another embodiment of the phase comparison device will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 6 shows the second phase comparison device.
It is a block diagram showing an embodiment. In the second embodiment
Describes the operation of the phase comparator 16 in the first embodiment.
The phase comparator 26 realized by digital signal processing is adopted.
To use. As shown in FIG. 6, the phase comparator 26 has a triangular wave
Generating circuit 261, holding circuit 262, and arithmetic circuit 263
, A D / A circuit 264, a timing generation circuit 265,
It is composed of

As shown in FIG. 7, the triangular wave generating circuit 261 is supplied with the extracted wobble signal SWB as a LOAD signal, and outputs the clock signal S generated by the PLL circuit 18 only during the period when the extracted wobble signal SWB is at the high level, for example.
A counting circuit for counting CK, and counts the number of counted clock signals SCK by n bits (n is an integer of 2 or more)
, Qn. The digital values Q1,..., Qn correspond to the amplitude level of the triangular wave output of the triangular wave generation circuit 163 in the first embodiment.

As shown in FIG. 7, the holding circuit 262 comprises three D-type flip-flops to which the outputs Q1,..., Qn of the triangular wave generating circuit 261 are inputted. In accordance with H.265, the timing signal is latched (held) at the timing designated by timing 1, timing 2, and timing 3, which are timing signals generated based on the pre-pit detection signal SPD.

That is, the holding circuit 262 latches the outputs Q1,..., Qn of the triangular wave generation circuit 261 with the signals of timing 1, timing 2, and timing 3 generated from the pre-pit detection signal SPD, and Output the measured value 1, the measured value 2, and the measured value 3, respectively.

Next, the arithmetic circuit 263, as shown in FIG.
It consists of an addition circuit and a division circuit for dividing by three. That is, the arithmetic circuit 263 converts the measured value 1, the measured value 2, and the measured value 3 output from the holding circuit 262 into the timing generation circuit 265.
Is added by the signal of the operation timing 1 supplied from the CPU, the addition result is output as the operation value 1, and the signal is divided by 3 by the signal of the operation timing 2 also supplied from the timing generation circuit 265 to perform the measurement. The calculated value DSCNT, which is the average of the value 1, the measured value 2, and the measured value 3, is output as a digital value.

The D / A circuit 264 converts the digitized arithmetic value DSCNT, which is the average of the measured value 1, the measured value 2, and the measured value 3, output from the arithmetic circuit 263, into a phase adjustment signal SCNT as an analog value. It is for converting to.

Next, the timing generation circuit 265 will be described with reference to FIG. The timing generation circuit 265 is composed of a logic circuit that receives the pre-pit detection signal SPD and the clock signal SCK as input signals. Based on the pre-pit detection signal SPD, the input signal from the triangular wave generation circuit 261 in the holding circuit 262, that is, A timing signal 1, a timing signal 2, and a timing signal 3 indicating a timing at which the signal is held, and an operation timing signal 1 and an operation timing signal 2 indicating a timing at which an operation is performed in the operation circuit 263 are output. Also, the D / A circuit 26
4, a conversion timing signal is output.

As shown in FIG. 2, the timing signals 1, 2, and 3 include pre-pits B2, B1, and B0 during one sync frame.
, A gate signal 1, a gate signal 2, a gate signal 3, and a pre-pit detection that open (become HI level) in a predetermined range including the timing at which each should exist (eg, the timing of 7T, 193T, 379T from the start position of the sync frame) It is generated by performing a logical operation (logical product) with the signal SPD.

More specifically, as shown in FIG. 9, the timing signal 1 is obtained by calculating the logical product of the gate signal 1 which opens in a predetermined range including the timing at which the pre-pit B2 should exist and the pre-pit detection signal SPD. 9 (time t1 in FIG. 9), and the timing signal 2
1 is generated by calculating the logical product of the gate signal 2 that opens in a predetermined range including the timing at which the 1 should exist and the pre-pit detection signal SPD (time t2 in FIG. 9), and the timing signal 3 should have the pre-pit B0. It is generated by calculating the logical product of the gate signal 3 that opens in a predetermined range including the timing and the pre-pit detection signal SPD (time t3 in FIG. 9). Therefore, for example, at time t4 in FIG.
As shown at t5, t6, and time t8, the pre-pit B2,
Even if it is the timing at which B1, B0 and prepit B1 should exist, if the prepit detection signal SPD is not generated (either the prepit is not actually recorded, or even if it is recorded, the prepit detector 13 detects it). Otherwise, the timing signals 1, 2, 3, and 2 are not generated.

The operation timing signal 1 indicates the timing at which the measured values latched in accordance with the timing signal 1, the timing signal 2, and the timing signal 3 are added and calculated. As shown in FIG. It occurs at the timing when the gate signal 3 closes (becomes L level). The operation timing signal 2 indicates the timing at which the result of the addition operation by the operation timing signal 1 is divided, and is used for performing the addition operation from the generation timing of the operation timing signal 1 in the operation circuit 263 (FIG. 8). Generated after a lapse of time equal to or longer than the required time. Then, the operation value DSCNT obtained by the division operation by the operation timing signal 2 becomes the operation value signal 2
Is held until a new division operation is performed. The operation timing signal 1 and the operation timing signal 2 also occur when the pre-pit detection signal SPD does not exist at the above-mentioned times t4, t5, and t6. In this case, the measurement value 1, the measurement value 2, and the measurement value Since the previous value 3 is held in the holding circuit 262, the operation value DSCNT is eventually held.

Therefore, for example, at time t12 shown in FIG. 9, even if a prepit that is not originally recorded is erroneously detected due to noise or the like, averaging with the measured values based on the prepits detected at times t10 and t11 is performed. Since the phase adjustment signal SCNT is generated, the effect of the erroneous detection at the time t12 does not remain until the next prepit detection, and the influence of the erroneous detection of the prepit due to noise or the like on the phase adjustment signal SCNT is reduced. It becomes possible to reduce.

As shown in FIGS. 3 to 9 described above, a configuration for adjusting the phase of the recording clock signal based on the phase adjustment signal obtained by comparing the phase of the signal carrying the phase information of the extracted wobble signal and the prepit detection signal. Then, the effect of generating a recording clock that follows the rotation of the disk with high accuracy can be expected.

In the embodiment shown in FIGS. 3 to 9, the recording medium has a pre-pit formed between wobbled groove tracks (land tracks).
Although the example in which the VD-R is adopted has been described, the present invention can also be applied to a recording medium in which prepits are formed on a groove track which is an information recording track. In the above description, the triangular wave generation circuit 16
3 and 261 both describe an example in which a triangular wave is generated during the period when the extracted wobble signal is at the H level, that is, half the period of one period of the extracted wobble signal. It may be configured to occur.

[0083]

As described above, in the phase comparator according to the present invention, a groove track as an information recording track wobbled by a wobble signal having a predetermined frequency, and a guide for guiding a recording beam to the information recording track. And a land track as a track, and is formed on the land track with a predetermined phase relationship with respect to the wobble signal, and is formed on an adjacent land track on the same straight line in the disk radial direction. In detecting the rotation phase of the disc when recording information on an optical disc having pre-pits that are not
Since the phase of the extracted wobble signal is compared with the phase of the pre-pit detection signal that has detected the pre-pit, even if the time axis of the extracted wobble signal in the desired groove track fluctuates due to crosstalk by the wobble signal of the adjacent groove track, It is possible to accurately detect the amount of fluctuation of the extracted wobble signal with respect to the inherent phase, and it is possible to generate a recording clock signal that is accurately synchronized with the rotation of the disk.

Even when the detection of the pre-pit signal is erroneous due to the influence of noise or the like, the phase of the extracted wobble signal extracted from the groove track and the phase of the pre-pit detection signal are compared to generate the phase adjustment signal. So do
The effect of erroneous detection of the pre-pit signal is reduced, and an accurate phase comparison device can be provided.

[Brief description of the drawings]

FIG. 1 is a relationship diagram showing an example of a configuration of a wobbling groove and a prepit.

FIG. 2 is a diagram illustrating an example of a recording format in a DVD-R31 of the embodiment.

FIG. 3 is a block diagram illustrating an overall configuration of an information recording device including a phase comparison device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a specific configuration example of a phase comparator 16 and a phase shifter 19 that generates a recording clock signal SCR in the phase comparison device according to the first embodiment of the present invention.

FIG. 5 is a schematic diagram of waveforms for explaining the operation of the circuit of FIG. 4;

FIG. 6 is a block diagram of a phase comparator in a phase comparison device according to a second embodiment of the present invention.

FIG. 7 is a diagram illustrating a triangular wave generation circuit 26 constituting the phase comparator 26;
FIG. 3 is a diagram illustrating a specific configuration example of a holding circuit 1 and a holding circuit 262.

FIG. 8 is a diagram showing a specific configuration example of an arithmetic circuit 263 constituting the phase comparator 26.

FIG. 9 is a timing chart for explaining the operation of the block diagram of FIG. 6;

[Explanation of symbols]

1 ··· Pickup 2 ··· Spindle motor 3 ··· Spindle driver 4 ··· Laser drive circuit 5 ··· Power control circuit 6 ··· Encoder 7 ··· Interface 8 · ... Reproduction amplifier 9 ... Decoder 10 ... Processor 11 ... Reference clock generator 12 BPF 13 Prepit signal detector 14 as prepit detection means · Pre-pit signal decoder 15 · · · · Wobble signal extractor 16 and 26 · · · · Phase comparator 17 · · · Phase comparator 18 · · · PLL circuit 19 · · · · as wobble signal extraction means Phaser 163, 261 ···· Triangular wave generation circuit as periodic signal generating means 164 ··· Sample hold circuit as holding means 31 ... DVD-R 262 operation circuit as a holding circuit 263 ... averaging means as ... holding means 264 ... D / A circuit 265 ... timing generator

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D044 AB01 AB05 AB07 BC02 CC04 GM02 GM15 5D090 AA01 BB04 CC01 CC04 CC16 DD03 DD05 EE02 EE12 EE15 FF07 FF15 GG03 GG10 GG28 HH01 5J106 CC21 DD35 DD42 EE15 JJ02 KK05

Claims (2)

[Claims] 1. An information recording track wobbled with a wobble signal having a predetermined frequency, and a guide track for guiding a recording beam to the information recording track, and further, the wobble signal is provided on the guide track. While being formed with a predetermined topological relationship,
A phase comparison device for comparing the phase of the wobble signal and the phase of the prepit in an information recording device that records information on an optical disc having prepits that are not formed on adjacent guide tracks on the same straight line in a radial direction. A wobble signal extraction unit for extracting the wobble signal; a prepit detection unit for detecting the prepit; a periodic signal synchronized with the extracted wobble signal and monotonically increasing for a period corresponding to the predetermined frequency. A phase comparison device comprising: a periodic signal generating unit that generates the signal; and a holding unit that latches an amplitude level of the periodic signal at a timing of detecting the pre-pit. 2. The phase comparison device according to claim 1, wherein the holding unit further includes an averaging unit that averages the latched amplitude level, and holds an output of the averaging unit.