JP2827238B2 - Optical disk recording and playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A Industrial Field of the Invention The present invention relates to an annular recording surface portion extending around a central hole, wherein clock information pits are radially disposed around the central hole, and between the clock information pits. The present invention relates to an optical disk recording / reproducing apparatus for recording / reproducing information on / from the recording track while rotating an optical disk having a large number of circling patterns surrounding the central hole with a recording track having a data recording area at a constant angular velocity. .

B. Summary of the Invention The present invention is directed to a recording track having a circular recording surface extending around a central hole, wherein clock concession pits are radially arranged around the central hole, and a recording track having a data recording area between the clock information pits is provided. In an optical disc recording / reproducing apparatus for recording / reproducing information on / from the recording tracks while rotating and driving a plurality of optical discs formed in a circular pattern surrounding the center hole at a constant angular velocity, the clock information pits of each recording track are provided. the basic clock of a predetermined frequency f ₁ generated from the reproduced output corresponding to the recording track
By recording or reproducing operation by performing frequency conversion on the channel clock of the M / N times the frequency f _2, is obtained by allowing high-quality recording and reproducing operation of high efficiency.

C. Prior Art In recent years, disk-shaped recording media such as optical disks and magneto-optical disks utilizing an optical or magneto-optical signal recording / reproducing method have been developed and are being supplied to the market. On these disc-shaped recording media, a read-only memory (ROM) type recording medium such as a so-called compact disc (CD: compact disc) or a user can write data once. Possible recording media of a so-called write-once type (write-once type) and recording media capable of rewriting (so-called overwriting) data such as a magneto-optical disk are known.

In an optical disk recording / reproducing apparatus using an optical disk using an optical or magneto-optical signal recording / reproducing method as a recording medium, the recording / reproducing length of information is controlled while rotating the optical disk at a constant angular velocity or a constant linear velocity by a spindle servo. Focus servo or tracking servo is applied to an optical head incorporating a laser diode that outputs laser light or a photodiode that detects reflected light of the laser light from the optical disk, and scans a recording track of the optical disk with the laser light. Information is recorded and reproduced.

Further, as one of the technologies for realizing a unified recording format for the above-mentioned various optical disks, a so-called sector disk in a hard disk in the magnetic disk field is used.
Similarly to the servo, servo signals by clock information pits or tracking information pits are recorded (so-called preformat) at predetermined intervals or at predetermined angles on concentric or spiral tracks on the disk, and the disk is rotated. A so-called sampled servo technique has been proposed in which, during driving, continuous servo control is performed by sampling and holding these discrete servo signals. As this type of optical disk, for example, an optical disk (10) having a recording format as shown in FIG. 10 has been conventionally known.

In the optical disk (10) shown in FIG. 10, an annular label portion (12) around the central hole (11) is provided, and further, an annular recording surface portion (13) extending around the label portion (12). ) Is provided. Then, the recording surface portion (1
3) is provided with concentric recording tracks (TK) for forming a large number of circling patterns surrounding the central hole (11), and each lap, that is, one lap track has a predetermined number m (for example, m). = 32) sectors (SC ₁ ), (SC ₂ ) to (SC
_m ), and a plurality of sectors having a corresponding relationship between the orbital tracks, such as a sector (SC ₁ ) in each orbital track, are arranged in the radial direction of the optical disc (10). It has become something. The optical disk (10) provided with such a recording track (TK) is mounted on an optical disk recording / reproducing apparatus and rotated in the direction of an arrow (R) to record or record information using a light beam. Provided for regeneration.

Each sector (SC ₁ ), (S
Each of C ₂ ) to (SC _m ) is provided with an address information section (AD) at the start end thereof, and is arranged along the recording track (TK) following this address information section (AD). A predetermined number n (for example, n = 43) blocks (B
L ₁ ) and (BL ₂ ) to (BL _n ). The blocks (BL ₁ ) and (BL ₂ ) to (BL _n ) are also inter-sector, for example, like the block (BL ₁ ) in each sector (SC ₁ ) and (SC ₂ ) to (SC _m ). A plurality of blocks having a corresponding relationship in the optical disk (10)
Are arranged in the radial direction. The block (B) in each such sector (SC ₁ ), (SC ₂ ) to (SC _m )
Each of L ₁ ) and (BL ₂ ) to (BL _n ) is provided with a servo information area (AR _S ) at the start end side and an information writing area (AR _D ) following the servo information area (AR _D ), so that unit recording is performed. It constitutes a division. Then, the servo information area (A) of each of the blocks (BL ₁ ), (BL ₂ ) to (BL _n )
The R _S), track centerline (K _C) interposed therebetween outer and tracking information pits staggered is located inside (Q _A) and the (Q _B), located on the track centerline (K _C) The formed clock information pits (Q _C ) are formed at predetermined intervals along the track center line (K _C ). The clock information pits (Q _C ) respectively correspond to the track center lines as shown in FIG. 11 in which the recording tracks (TK _n−1 ), (TK _n ), and (TK _{n + 1} ) are enlarged. They are linearly arranged in a direction orthogonal to (K _C ), that is, in a radial direction of the optical disc (10).

In an optical disk recording / reproducing apparatus using the optical disk (10) as a recording medium, a clock information pit (Q _C ) formed at predetermined rotation angles on the recording track (TK) as shown in FIG. of on the basis of the reproduction output phi _C to form a channel clock phi _CH performing clock recovery operation by a so-called PLL, the channel clock phi _CH
Using thereby recording and reproducing the information with respect to the information writing region (AR _D).

D Problems to be Solved by the Invention By the way, in the conventional optical disk recording / reproducing apparatus for recording / reproducing information while rotating and driving the optical disk (10) employing the sampling format as described above at a constant angular velocity, the optical disk (10 ) Recording track (TK)
Each of the recording tracks (TK) is formed by using a channel clock φ _CH formed by a so-called PLL clock reproduction operation based on a reproduction output φ _C obtained at every predetermined rotation angle by the above clock information pit (Q _C ). information the write area (recording and reproducing information with respect to AR _D)) of the recording density of more information becomes the recording track on the outer circumferential side and becomes lower, the utilization efficiency of the recording medium is disadvantageously poor.

Therefore, the present invention has been made in view of the above-described conventional problems,
Clock information pits are radially arranged around the center hole on an annular recording surface portion extending around the center hole, and a plurality of recording tracks surrounding the center hole are formed by recording tracks having a data recording area between the clock information pits. The object of the present invention is to improve the use efficiency of a recording medium in an optical disk recording / reproducing apparatus for recording / reproducing information on / from the recording track while rotating an optical disk formed in a pattern at a constant angular velocity. The present invention provides an optical disc recording / reproducing apparatus having a novel configuration that enables high-quality, high-efficiency recording / reproducing operation by making the recording density of information the same between the recording track of the recording track and the recording track on the outer peripheral side.

E. Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has a structure in which clock information pits are arranged radially around the central hole on an annular recording surface portion extending around the central hole. Recording and reproduction of information with respect to the recording tracks is performed while rotating an optical disk in which recording tracks having data recording areas between the clock information pits are formed in a number of circling patterns surrounding the central hole at a constant angular velocity. in the optical disk recording and reproducing apparatus for performing clock recovery means and, in the basic clock a clock frequency f ₁ for generating a reference clock of a predetermined frequency f ₁ from the reproduction output of the clock information pits
And a frequency converting means for forming a channel clock of a frequency f ₂ which is converted to M / N times, and a control means for varying the frequency conversion ratio M / N of the frequency converting means according to the recording track number of the optical disc The recording / reproducing of information on the recording track is performed using the channel clock frequency-converted by the frequency converting means. Further, the present invention provides the optical disk recording / reproducing apparatus, wherein a phase control unit of the channel clock is provided in a reproduction processing system to which a frequency-converted channel clock obtained by the frequency converting unit is supplied, and The phase of the channel clock is controlled so that the level difference between the leading edge portion and the trailing edge portion of the reproduced signal to be reproduced becomes zero. Further, the present invention provides the optical disc recording and reproducing apparatus,
A digital equalizer for a reproduction signal reproduced from a recording track of the optical disk is provided in a reproduction processing system, and the digital equalizer is operated by a frequency-converted channel clock obtained by the frequency conversion means.

In the optical disc recording / reproducing apparatus according to the present invention, the clock reproducing means controls the optical disc based on the reproduction output of the clock information pits obtained at every predetermined rotation angle from the recording track of the optical disc rotated at a constant angular velocity. to generate a synchronized with the basic clock of a constant frequency f _1. Also,
The frequency conversion means is a clock frequency of the basic clock.
The f ₁ is converted to M / N times to form a channel clock of f ₂ = f ₁ · M / N becomes frequency f _2. Then, the control means changes the frequency conversion ratio M / N of the frequency conversion means according to the recording track number of the optical disc. Channel clock frequency converted by the frequency converting means is synchronized with the optical disc, moreover, it becomes the frequency f ₂ is changed depending on the recording track number of the optical disc.
By using the channel clock frequency-converted by the frequency conversion means, information can be recorded and reproduced with substantially uniform recording density on each recording track on the optical disk.

Further, in the optical disk recording / reproducing apparatus according to the present invention, the channel clock phase control means provided in the reproduction processing system to which the frequency-converted channel clock obtained by the frequency conversion means is supplied, The phase of the channel clock is controlled so that the level difference between the leading edge portion and the trailing edge portion of the reproduced signal to be reproduced becomes zero. The reproduction processing system can reliably perform the reproduction operation with the bit clock in the optimal phase state by providing the phase control means.

Further, in the optical disk recording / reproducing apparatus according to the present invention, the digital equalizer provided in the reproduction processing system operates from the frequency-converted channel clock obtained by the frequency converting means, thereby reproducing from the recording track of the optical disk. The equalizer characteristic given to the reproduced signal is automatically changed, and the optimum equalizer processing operation is always performed on the reproduced signal.

G Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

In the embodiment shown in the block diagram of FIG. 1, the present invention is applied to an optical disk recording / reproducing apparatus using a write-once optical disk (10) adopting the sampling format shown in FIG. 10 as a recording medium. In this optical disk recording / reproducing apparatus, the optical disk (10) is driven to rotate at a constant angular velocity by a spindle motor (20), and an optical head (21) scans a recording track of the optical disk (10) with a laser beam. And optically records and reproduces digital data in a data format conforming to the CD standard.

In this optical disk recording and reproducing apparatus, the optical head (21) is driven by a laser driving circuit (22) to output a laser beam for recording and reproducing information,
A photodetector or the like for detecting the reflected light of the laser light emitted by the laser diode by the optical disk (10) is built in, and the recording track of the optical disk (10) is scanned by the laser light output by the laser diode. , Recording track (TK) of the above optical disc (10)
Is recorded and reproduced.

The detection output obtained by the photodetector obtained by scanning the recording track (TK) of the optical disk (10) with the reproduction RF signal from the optical head (21), that is, the laser beam output from the laser diode, A reproduction RF signal for an information recording area (AR _D ) of a track (TK) is converted from a first preamplifier (23) to a digital equalizer via a reproduction processing analog-to-digital (A / D) converter (24). is supplied to the (25), and is decoded to reproduce the digital data D _OUT by the decoder from the equalizer process is performed at the digital equalizer (25) (26). In addition, the recording track (T
The RF signal reproduced by the optical head (21) for the servo area (AR _S ) of K) is supplied from the second preamplifier (27) to the head servo circuit (28) and the spindle servo circuit (29). It is supplied to a clock recovery circuit (30).

The head servo circuit (28) includes the optical head (21)
Of controlling the biaxial actuator (not shown) for driving the objective lens tracking servo and focus servo performs based on the reproduction RF signal supplied from the optical head (21), the aforementioned tracking information pits (Q _A) ,
A tracking error is detected based on the reproduction output of (Q _B ) to perform tracking servo control, and reproduction of a non-pit area between the tracking information pit (Q _B ) and the clock information pit (Q _C ). The focus servo control is performed by detecting a focus error based on the output.

The spindle servo circuit (29) detects a rotational angular velocity error of the spindle motor (20) based on a reproduction output of the clock information pit (Q _C ) and drives the spindle motor (20). By performing feedback control of (40), spindle servo control is performed by the spindle motor (20) so as to keep the rotation angular velocity of the optical disc (10) constant.

Further, the clock reproduction circuit (30) performs clock reproduction by a so-called PLL based on a reproduction output of the clock information pit (Q _C ) in the reproduction RF signal supplied from the optical head (10). to form a basic clock phi ₁ of predetermined frequency f ₁ in synchronism with the rotation of the optical disk (10).

Here, the clock recovery circuit (30) is, for example, a second
As shown in the block diagram of the figure, the servo area (A) of the recording track (TK) supplied from the optical head (10)
R _S ), a differentiation circuit (31) for differentiating the reproduced RF signal, a zero-cross detection circuit (32) for performing zero-cross detection on a differentiated output waveform by the differentiation circuit (31), and a detection output from the zero-cross detection circuit (32) are ANDed. A phase comparator (34) supplied through a gate (33), and a voltage-controlled oscillator (3) in which the phase comparison by the phase comparator (34) is supplied as a control voltage through a low-pass filter (35).
6) Oscillation output f ₁ by the voltage-controlled oscillation circuit (36)
And a frequency divider (37) for dividing the frequency by 1/270.
In the clock recovery circuit (30), the AND gate (33) outputs only the zero-cross detection output of the clock information pit (Q _C ) by the gate control signal supplied from the frequency divider (37). The extracted signal is supplied to the phase comparator (34). In addition, the phase comparator (3
4) Compare the phase of the zero-cross detection output for the reproduction output of the clock information pit (Q _C ) with the phase of the 1/270 frequency division output by the frequency divider (37) to detect the phase error. I do. Then, the voltage-controlled oscillation circuit (36)
Is controlled by a control voltage corresponding to the phase error detected by the phase comparator (34),
Clock reproduction is performed by a so-called PLL in which the oscillation phase is fixed to the phase of the zero-cross detection output for the reproduction output of the clock information pit (Q _C ), and the recording track ( A predetermined frequency f _{1 that} divides the clock information pit (Q _C ) on TK) by 270.
To form the basic clock φ ₁ of.

Predetermined frequency obtained by the clock recovery circuit (30)
The basic clock φ ₁ of f ₁ is obtained by the above head servo circuit (28)
And an operation clock to the spindle servo circuit (29) and to the frequency conversion circuit (50).

Said frequency converting circuit (50), the basic clock phi ₁ obtained in the above clock recovery circuit (30), a frequency converter for converting the clock frequency f ₁ to M / N times the frequency f ₁ · M / N The frequency conversion ratio M / N is controlled by the system controller (41) so that the frequency conversion ratio M / N changes according to the track number of the recording track (TK) scanned by the optical head (21). .

It said frequency converting circuit (50), for example as shown in FIG. 4, the first minute of the clock frequency f ₁ of the fundamental clock phi ₁ 1 / N frequency division obtained by the clock recovery circuit (30) Frequency divider (51), frequency-divided output f ₁ by the first frequency divider (51)
/ N is supplied to the phase comparator (52) and the phase comparator (5
A voltage-controlled oscillation circuit (54) in which the phase comparison by 2) is supplied as a control voltage via a low-pass filter (53),
The oscillation output f ₂ of the voltage controlled oscillator (54) is 1 / M
It is composed of a second frequency divider (37) for frequency division. The phase comparator (52) is configured to determine the phase of the divided output f1 / N from the _first divider (51) and the phase of the divided output f2 / M from the _second divider (55). And the phase error is detected. The voltage-controlled oscillation circuit (54) controls the oscillation phase with a control voltage corresponding to the phase error detected by the phase comparator (34), so that f ₂ = f ₁ · M in / N becomes frequency f _2, the oscillation in the first frequency divider (51) by dividing the output f ₁ / N of the phase i.e. basic clock phi ₁ of the phase obtained in the above clock recovery circuit (30) The phase is fixed.

Here, in the frequency conversion circuit (50), the first and second frequency dividers (51) and (55) are constituted by so-called programmable dividers, and the control data D is transmitted from the system controller (41). _N, the first and second frequency divider by D _M (51), by the division value of (55) 1 / N, 1 / M is variably controlled, its frequency conversion ratio M / N The frequency f is changed according to the track number of the recording track (TK) scanned by the optical head (21), and becomes higher as the recording track (TK) scanned by the optical head (21) is closer to the outer circumference. performs frequency conversion processing for converting to _2, the information substantially constant recording density to form a channel clock phi ₂ for recording and reproducing for each recording track (TK).

The channel clock phi ₂ obtained by said frequency converting circuit (50), the recording processing system of the encoder (42)
As well as to the A / D converter (24) and the digital equalizer (25) of the reproduction processing system via the phase control circuit (60).

The encoder (42) is fed during the recording mode, the recording data D _IN is converted to a recording timing pulse synchronized with the channel clock phi ₂ obtained by said frequency converting circuit (50) the laser drive circuit (22) and performs laser by pulsing the diodes, additional recording on the recording track of the optical disk as shown in FIG. 5 (10) (TK) of the optical head (10) in accordance with the recording data D _iN.

By thus performing the recording operation by the recording processing system using a channel clock phi ₂ of the frequency conversion processed obtained by said frequency converting circuit (50), the optical disc which is rotated at a constant angular velocity (10) Information can be additionally recorded at a substantially constant recording density on the inner peripheral side and the outer peripheral side with respect to the information writing area (AR _D ) of each recording track (TK).

The information writing area (AR) of the optical disc (10)
In additional recording information to _D) is above the data block _{(BL 1), (BL 2} ) ~ (BL n) each servo area for each (A
The recording of the phase pit (Q _P ) is performed immediately after R _S ).

In the reproduction processing system for reproducing the information additionally recorded on each recording track (TK) on the optical disk (10), the channel clock φ ₂ obtained by the frequency conversion circuit (50) is used. Is supplied with a channel clock φ ₂ ′ for reproduction processing via a phase control circuit (60), and the A / D converter (24) and the digital equalizer (25) operate on the channel clock φ ₂ ′. It has become.

The phase control circuit (60), for example, as to shown in FIG. 6, form a channel clock phi _{2 'for} reproduction processing channel clock phi ₂ by phase obtained by said frequency converting circuit (50) And a multi-stage buffer amplifier (61 ₁ ), (61 ₂ ) to (62 _n ) connected in series,
A switch (62) for selecting each output of the buffer amplifiers (61 ₁ ) and (61 ₂ ) to (62 _n ) is provided, and the A / D converter (2
Subtractor (65) subtracts the latch data by the two latch circuits (63) and (64) that latches the reproduced data _DPB from 4), and the subtracted output value obtained by the subtracter (65) The adjustment logic (67) is configured to control the selection operation of the switch (62) in accordance with the output of the comparator (66) that compares the switch with a predetermined value. This phase control circuit (60)
The reproduced RF from the servo area of the recording track on the optical disk as shown in FIG. 6 (10) (TK) (AR S)
In which by paying attention to the spread of the reproduced RF signal for the signal of the phase pit (Q _P) corrects the phase, sampling level L _F and trailing edge portion of the front edge portion of the reproduced RF signal for the phase pit (Q _P) each latch circuit and a sampling level L _B of (63), (64), and subtracts the output value by the subtractor (65) that is, the respective sampling level L _F, channel clock level difference becomes zero L _B phi Adjustment logic (67) so that ₂ 'is selected by the switch (62)
Controls the selection operation of the switch (62).

As described above, by performing the reproduction process using the channel clock φ ₂ ′ obtained through the phase control circuit (60), the reproduction processing system allows the optical head (21) to reproduce the optical disk (10). For the reproduction signal obtained by scanning the recording track (TK), the reproduction process can always be performed with the channel clock φ ₂ ′ of the optimum phase, and the error occurrence rate is reduced to achieve a highly reliable reproduction operation. Will be able to do it.

The digital equalizer (25) supplied with the reproduction data D _PB from the A / D converter (24) performs equalization processing on the reproduction data D _PB using the channel clock φ ₂ ′ as an operation clock. Thus, for example, the configuration is as shown in FIG.

That is, the digital equalizer (25) shown in FIG.
Comprises four latch circuits (71), (72), (73), and (74) using the channel clock φ ₂ ′ as an operation clock, and the reproduced data D _PB is _supplied to the first latch circuit (71). The latch output from the first latch circuit (71) is supplied to a second latch circuit (72) and is also applied to a synthesizer (77) via a coefficient unit (75). The latch output from the second latch circuit (72) is supplied to the third latch circuit (73) and is also given to the synthesizer (77). The combined output from the combiner (76) is supplied to the combiner (76) via a combiner (77), and the reproduced data D that has been subjected to the equalizer processing is outputted through a fourth latch circuit (74).
It is output as _PB '. The combiner (76) outputs each latch output from the first and third latch circuits (71) and (73) supplied through the coefficient units (75) and (76) to the second A combining process of subtracting from the latch output by the latch circuit (72) is performed.

The digital equalizer (25) having such a configuration sets the clock cycle of the channel clock φ ₂ ′ to ΔT = 1 /
As f _2, FIG. 9 of (A) to indicate such an impulse response h (t) h (t) = δ (t) -K {δ (t + ΔT) + δ (t-
ΔT)｝ characteristics. The above impulse response h (t)
Is converted into a frequency characteristic F {h (t)} by Fourier transform. Can be represented by

Therefore, the digital equalizer (25) exhibits an equalizer characteristic that changes with the clock period ΔT (ΔT = 1 / f ₂ ) of the channel clock φ ₂ ′ as shown in FIG. 9B, and this equalizer characteristic Is given to the reproduced RF signal from the recording track (TK) of the optical disc (10) as shown in FIG. 9 (B). FIG. 9 shows a recording track (T) on the inner peripheral side of the optical disc (10).
An example of the equalizer characteristics for the reproduced RF signal from K) is shown by a solid line, and an example of the equalizer characteristics for the reproduced RF signal from the outer recording track (TK) is shown by a broken line.

Thus, the reproduction data D _PB from the A / D converter (24)
The reproduction data D _PB is subjected to equalization processing using the channel clock φ ₂ ′ as an operation clock by the digital equalizer (25) supplied with the reproduction RF signal from the recording track (TK) of the optical disc (10). The equalizer characteristics can be automatically changed according to the frequency characteristics of the signal, and the optimum equalizer processing can always be performed to perform the high-quality reproduction operation.

H Effect of the Invention In the optical disk recording / reproducing apparatus according to the present invention, the clock reproducing means is provided based on the reproduction output of the clock information pit obtained at every predetermined rotation angle from the recording track of the optical disk rotated at a constant angular velocity. generating a reference clock of a predetermined frequency f ₁ which is synchronized to the optical disc, by the frequency converting means for frequency converting ratio M / N in accordance with a recording track number of the optical disc is variably controlled by the control means,
Forming a channel clock of the basic clock frequency f ₁ of the clock is converted to M / N times by the frequency converting means f ₂ = f ₁ · M / N becomes frequency f _2. Frequency-converted channel clocks are at said frequency converting means is synchronized to the optical disc, moreover, since as the frequency f ₂ is changed depending on the recording track number of the optical disc, using the channel clock recording By performing the reproduction process, information can be recorded and reproduced with substantially uniform recording density for each recording track on the optical disc, and the utilization efficiency of the recording medium can be increased to perform high-density recording. .

Further, in the optical disk recording / reproducing apparatus according to the present invention, the recording track of the optical disk is controlled by the phase control means of the channel clock provided in the reproduction processing system to which the frequency-converted channel clock obtained by the frequency converting means is supplied. By controlling the phase of the channel clock so that the level difference between the leading edge portion and the trailing edge portion of the reproduced signal reproduced from the channel signal becomes zero, a channel clock in an optimal phase state can be obtained. By using this, the reproduction operation can be reliably performed in the reproduction processing system.

Further, in the optical disk recording and reproducing apparatus according to the present invention,
By operating a digital equalizer provided in a reproduction processing system with a frequency-converted channel clock obtained by the frequency conversion means, an equalizer characteristic given to a reproduction signal reproduced from a recording track of the optical disk is automatically changed. Therefore, an optimal equalizer processing operation can always be performed on the reproduced signal, and high-density recorded information can be reproduced with high quality.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of an optical disk recording / reproducing apparatus according to the present invention, FIG. 2 is a block diagram showing a configuration example of a clock reproducing circuit used in the optical disk recording / reproducing apparatus, and FIG. 4 is a time chart for explaining the operation of the reproducing circuit, FIG. 4 is a block diagram showing a configuration example of a frequency conversion circuit used in the optical disk recording / reproducing apparatus, and FIG. 5 is a diagram for explaining the operation of the frequency converting circuit. FIG. 6 is a block diagram showing a configuration example of a phase control circuit used in the optical disk recording / reproducing apparatus, FIG. 7 is a time chart for explaining the operation of the phase control circuit, and FIG. FIG. 9 is a block diagram showing a configuration example of a digital equalizer used in the recording / reproducing apparatus. FIG. 9 is a characteristic diagram for explaining the operation of the digital equalizer. FIG. 10 is a schematic diagram showing a recording format of a general optical disk adopting a sampling format, and FIG. 11 is a schematic diagram for explaining an operation of reproducing a channel clock for the optical disk. (10) Optical disk (21) Optical head (24) A / D converter (25) Digital equalizer (26) Decoder (30) Clock recovery circuit (41) System Controller (50) Frequency conversion circuit (Q _C ) Clock pit

Claims (3)

(57) [Claims] A clock information pit is radially disposed around the central hole on an annular recording surface portion extending around the central hole, and a recording track having a data recording area between the clock information pits is formed on the central hole. An optical disk recording / reproducing apparatus for recording / reproducing information on / from the recording track while rotating an optical disk formed in a number of orbital patterns surrounding the pattern at a constant angular velocity, comprising the steps of: a clock reproducing means for generating _a basic clock, a frequency conversion means for forming a channel clock of a frequency f ₂ which converts the clock frequency f ₁ of the fundamental clock to M / N times a frequency conversion ratio of the frequency converter Control means for changing the M / N according to the recording track number of the optical disc, wherein the frequency conversion means An optical disc recording / reproducing apparatus for recording / reproducing information on / from the recording track using a frequency-converted channel clock. 2. A reproduction processing system to which a frequency-converted channel clock obtained by said frequency conversion means is supplied, said phase control means for said channel clock being provided, and a leading edge of a reproduction signal reproduced from a recording track of said optical disk. The optical disk recording / reproducing apparatus according to claim 1, wherein the phase of the channel clock is controlled so that the level difference between the portion and the trailing edge portion becomes zero. 3. A reproduction processing system comprising a digital equalizer for a reproduction signal reproduced from a recording track of the optical disk, wherein the digital equalizer is operated by a frequency-converted channel clock obtained by the frequency conversion means. The optical disk recording / reproducing apparatus according to claim 1, wherein