JP3180338B2 - Rotation control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation control device suitable for application to a recording device for a magneto-optical disk, and more particularly to a rotation control device suitable for a recording device for a disk with wobbled tracks. About.

[Summary of the Invention]

According to the present invention, there is provided a rotation control device for rotating a disk in which address information is recorded in a guide groove meandering at a predetermined cycle formed in advance on a disk, a meandering cycle detecting means for detecting a predetermined cycle of the guide groove, A first speed control means for generating a first speed control signal based on the frequency signal detected by the meandering cycle detecting means, and a demodulating means for demodulating recording information recorded in the guide groove meandering at the predetermined cycle. Synchronizing signal detecting means for detecting a synchronizing signal from demodulated recording information, second speed controlling means for generating a second speed control signal based on the synchronizing signal detected by the synchronizing signal detecting means, Switching means for switching between the first speed control means and the second speed control means, a parity check means for checking the parity of the demodulated record information, and a parity check means. Switching control means for switching the switching means from the second speed control means to the first speed control means when an error of a predetermined number or more is detected, and a speed control signal selected by the switching means. In this configuration, the rotation is performed on the basis of the above, and the predetermined number of times in the parity check means is changed according to the operation mode, so that good rotation control can be performed.

[Conventional technology]

In an optical recording medium, for example, a magneto-optical disk, a guide groove for tracking is previously formed in a spiral or concentric shape on the disk, and the guide groove (so-called groove) formed in advance and a land portion between the grooves are formed. As a recording track, a recording track has been developed on which data is recorded and reproduced by utilizing a magneto-optical effect along the track direction. Such a recording medium magneto-optically records and reproduces data while optically detecting the guide groove and applying tracking servo.

By the way, in a recording medium having such a groove (or a land between the grooves) as a recording track, the groove is previously displaced in the width direction at a predetermined interval (meandering / wobbling) at the time of forming the disk, and the address is determined by this width direction displacement. Control information such as information and synchronization information is recorded.

In this case, for example, synchronization information of a constant frequency is recorded by wobbling of the groove at a constant interval, and address information is recorded on the wobbled groove by phase modulation.

The spindle servo at the time of data recording is performed using the wobbled groove formed on the magneto-optical disk. That is, at the time of data reproduction, control information for the spindle servo can be obtained from the reproduced RF signal or the like, but at the time of data recording, such an RF signal cannot be obtained. Therefore, it is necessary to perform the spindle servo with the information obtained from the wobbled groove. I have to.

[Problems to be solved by the invention]

By the way, the information obtained from the wobbled groove includes the synchronization information of a constant frequency and the address information in the phase modulation as described above. When performing the spindle servo at the time of data recording, the wobbling is performed at the time of starting the rotation of the disk. Servo control by speed control is performed so that the frequency (that is, synchronization frequency) becomes constant, and when the speed becomes almost the target speed, servo control is performed based on the clock component and the like included in the phase modulation data, and an accurate spindle The servo control of the motor is enabled.

In this case, the switching between the servo control based on the wobbling frequency and the servo control based on the phase modulation data is performed, for example, by checking the parity included in the phase modulation data, as shown in JP-A-1-302575, When it is determined that the reading of the phase modulation data has been performed, the servo control based on the phase modulation data is performed. When it is determined that the reading of the phase modulation data is not correctly performed, the servo control based on the wobbling frequency is performed.

FIG. 3 is a diagram showing an example of a circuit for switching the servo control. In FIG. 3, (1) shows an error detection circuit, and this error detection circuit (1) shows the phase modulation data recorded in the wobbled groove. A circuit that checks parity and determines whether or not data has been read correctly. The circuit outputs a high-level signal "1" when data is correctly read, and outputs a low-level signal "0" when data is not correctly read. Circuit. In the figure, reference numeral (2) denotes a synchronization generation circuit. The synchronization generation circuit (2) is a circuit for generating a synchronization signal from a clock recorded as phase modulation data in a wobbled groove.

Then, the detection output of the error detection circuit (1) is
The signal is supplied to the first input terminal of the NOR gate (3) and to the D input terminal of the first D flip-flop (4).
The synchronization signal output from the synchronization generation circuit (2) is supplied to the clock input terminal of the first D flip-flop (4), and the Q output of the first D flip-flop (4) is
The signal is supplied to the second input terminal of the NOR gate (3) and to the D input terminal of the second D flip-flop (5).
Then, a synchronization signal output from the synchronization generation circuit (2) is supplied to a clock input terminal of a second D flip-flop (5), and a Q output of the second D flip-flop (5) is
The signal is supplied to the third input terminal of the NOR gate (3) and to the D input terminal of the third D flip-flop (6).
Then, the synchronization signal output from the synchronization generation circuit (2) is supplied to the clock input terminal of the third D flip-flop (6), and the Q output of the third D flip-flop (6) is
The signal is supplied to the fourth input terminal of the NOR gate (3).

Then, the logic output of the NOR gate (3) is supplied to the K input terminal of the JK flip-flop (7), and the detection output of the error detection circuit (1) is supplied to the JK flip-flop (7).
And a synchronization signal output from the synchronization generation circuit (2) to the clock input terminal CK of the JK flip-flop (7). Then, the Q output of the JK flip-flop (7) is supplied to a switching signal output terminal (8).

When a high-level signal “1” is output from the switching signal output terminal (8), servo control based on the phase modulation data is performed. When a low-level signal “0” is output,
Performs servo control based on the wobbling frequency.

By configuring the switching signal generation circuit for switching the servo control in this manner, when the parity check data output from the error detection circuit (1) is a high level signal "1" and no error occurs, the NOR gate ( The logic output of 3) becomes a low level signal "0", and a high level signal "1" is obtained as a Q output of the JK flip-flop (7).
A high-level signal "1" is output from the switching signal output terminal (8). Therefore, servo control based on the phase modulation data is performed.

When the parity check data output from the error detection circuit (1) is a low level signal “0”,
When the low level signal is "0" four times in succession, the low level signal "0" is output from the switching signal output terminal (8). That is, the parity check data output from the error detection circuit (1) is synchronized with the synchronization signal output from the synchronization generation circuit (2), and the first, second, and third D flip-flops (4), (5) , (6). When the parity check data indicates that an error has occurred four consecutive times, together with the data supplied directly from the error detection circuit (1) to the NOR gate (3) (ie, four consecutive low-level signals). When it is "0"), the logical output of the NOR gate (3) becomes a high-level signal "1" and the JK
A low level signal "0" is obtained as a Q output of the flip-flop (7), and a low level signal "0" is output from the switching signal output terminal (8). Therefore, servo control based on the wobbling frequency is performed.

In this way, when an error occurs four times consecutively in the parity check of the phase modulation data, the servo control based on the phase modulation data is switched to the servo control based on the wobbling frequency.

However, if the switching is performed simply by the parity check of the phase modulation data, when the spindle motor is controlled stably by the servo control based on the phase modulation data, the phase modulation data is temporarily read out for some reason. However, when a continuous error occurs, the servo control is switched to the wobbling frequency, and the spindle servo control becomes unstable at the time of switching.

In particular, servo control based on information obtained from the wobbled groove is mainly performed at the time of data recording. When such servo control switching is performed at the time of data recording, data written at the time of servo control switching is performed. There is a possibility that the recording state of the data may be deteriorated, which may be a factor of deteriorating the data error rate.

SUMMARY OF THE INVENTION In view of the foregoing, an object of the present invention is to enable a spindle servo of a disk of this type to be performed favorably during data recording.

[Means for solving the problem]

According to the present invention, there is provided a rotation control device for rotating a disk in which address information is recorded in a guide groove meandering at a predetermined cycle formed in advance on a disk, a meandering cycle detecting means for detecting a predetermined cycle of the guide groove, A first speed control means for generating a first speed control signal based on the frequency signal detected by the meandering cycle detecting means, and a demodulating means for demodulating recording information recorded in the guide groove meandering at the predetermined cycle. A synchronization signal detecting means for detecting a synchronization signal from demodulated recording information,
Second speed control means for generating a second speed control signal based on the synchronization signal detected by the synchronization signal detection means;
A switching unit for switching between the first speed control unit and the second speed control unit; a parity check unit for checking the parity of the demodulated recording information; and a predetermined number of errors detected by the parity check unit. A switching control means for switching the switching means from the second speed control means to the first speed control means, and rotational driving is performed based on a speed control signal selected by the switching means. The predetermined number of times in the parity check means is changed according to the operation mode.

[Action]

With this configuration, the switching from the second speed control based on the synchronization signal of the information recorded in the guide groove to the first speed control based on the meandering frequency of the guide groove is started by rotating the disk. When quick control such as time or access is desired, switching is performed with a small number of error occurrences, and when stable control such as data recording is desired, control is performed.
By performing switching with a relatively large number of error occurrences, good spindle servo control according to the operation mode can be performed.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIG. 1 and FIG.

FIG. 1 is a diagram showing an overall configuration of a rotation control device of the present embodiment, which is a servo control circuit for a spindle motor of a magneto-optical disk, and which is a servo control circuit for controlling CLV (constant linear velocity). This servo control circuit is used at the time of access or at the time of access (track jump or the like). In FIG. 1, (11) indicates a wobbling detection circuit, and this wobbling detection circuit (11) is a circuit for detecting the wobbling frequency of a track (groove) formed on a magneto-optical disk (not shown). In the example, the wobbling frequency of 22.05 kHz is detected when the servo control of the spindle motor is performed accurately. The detected frequency signal is supplied to a speed detection circuit (12), and the speed detection circuit (12) detects the rotation speed of the spindle motor. The detected speed information is supplied to a control circuit (13), and the control circuit (13) creates and outputs a control signal for the spindle motor (21) according to the speed.

Reference numeral (14) denotes a synchronization detection circuit. The synchronization detection circuit (14) detects a clock recorded as phase modulation data in a wobbled groove and generates a synchronization signal. 6.3kHz when is normal
Is detected. The synchronization signal output from the synchronization detection circuit (14) is output to the speed detection circuit (1
5), and the speed detection circuit (15) detects the rotation speed of the spindle motor. The detected speed information is supplied to a control circuit (16), and the control circuit (16) creates and outputs a control signal for the spindle motor (21) according to the speed.

The control signals output from the control circuits (13) and (16) are supplied to the first and second fixed contacts (31) and (32) of the first changeover switch (30), and are selectively supplied to the spindle. It is supplied to the motor (21) side.

Further, the synchronization signal output from the synchronization detection circuit (14) is
The frequency signal is supplied to a 1/3 frequency divider (17) to generate a frequency signal near 2.1 KHz, and the frequency signal divided by the 1/3 frequency divider (17) is supplied to a phase comparator (18). Then, a reference signal supplied from a reference oscillator (19) that oscillates a 2.1 KHz frequency signal is supplied to a phase comparator (18), and a phase difference between the divided signal and the reference signal is detected. Then, the detected phase difference information is supplied to the control circuit (20), and the control circuit (20)
Creates and outputs a control signal for the spindle motor (21) according to the phase difference.

Then, the control signal output from the control circuit (20) is
Is supplied to the second fixed contact (42) of the changeover switch (40), and is supplied to the spindle motor (21) side according to the switching state of the second changeover switch (40).
In this case, the second changeover switch (40) is adapted to be operated in conjunction with the first changeover switch (30) under the control of a changeover signal generation circuit (50) to be described later. The first fixed contact (41) of the switch (40) is a terminal connected to none. The movable contacts (33) and (43) of the first and second changeover switches (30) and (40)
Is supplied to an adder (22) for addition, and the added output is supplied to a spindle motor (21).

Reference numeral (23) denotes a data detection circuit. The data detection circuit (23) is a circuit for detecting data recorded in a wobbled groove by phase modulation, and supplies the detected data to a decoder (24). The synchronization signal output from the synchronization detection circuit (14) is supplied to the decoder (24), and the detection data is decoded based on the synchronization signal. The data obtained by decoding is supplied to a central control unit (CPU) (25) for controlling data writing.

The parity check data and the synchronization signal detected from the reproduced data by the decoder (24) are transmitted to the central control unit (2
5) and the switching signal generation circuit (50).

Here, the configuration of the switching signal generating circuit (50) is shown in FIG. 2. In FIG. 2, (51) shows a parity check data input terminal, and (52) shows a synchronization signal input terminal. The parity check data obtained at the input terminal (51) is supplied to a first input terminal of a 4-input NOR gate (56),
It is supplied to the D input terminal of the first D flip-flop (53). Then, the Q of the first D flip-flop (53)
The output is provided to a second input of a NOR gate (56) and to a D input of a second D flip-flop (54). Then, the second D flip-flop (54)
Is supplied to the third input terminal of the NOR gate (56) and to the D input terminal of the third D flip-flop (55). Then, the Q output of the third D flip-flop (55) is supplied to the fourth input terminal of the NOR gate (56), and the D output of the fourth D flip-flop (57) is supplied.
Supply to input terminal. The Q output of the fourth D flip-flop (57) is connected to the first input of the three-input NOR gate (60).
, And to the D input terminal of the fifth D flip-flop (58). Then, the Q output of the fifth D flip-flop (58) is supplied to the second input terminal of the NOR gate (60) and to the D input terminal of the sixth D flip-flop (59). The Q output of the sixth D flip-flop (59) is connected to a NOR gate (6
0) to the third input terminal. Also, the input terminal (52)
The synchronizing signal obtained in (1) to (5), (54), (55), (57), (58), (59)
Clock input terminal.

Then, the logical output of the three-input NOR gate (60) is supplied to one input terminal of the OR gate (61).

In the drawing, reference numeral (62) denotes an input terminal to which a recording control signal is supplied from the central control unit (25). When data is recorded on a magneto-optical disk, a low level signal "0" is supplied. At this time, the high-level signal “1” is supplied.
Then, the recording control signal obtained at the input terminal (62) is supplied to the other input terminal of the OR gate (61).

The logical output of the 4-input NOR gate (56) is supplied to one input terminal of the AND gate (63), and the logical output of the OR gate (62) is supplied to the other input terminal of the AND gate (63). I do. The logical output of the AND gate (63) is
The parity check data supplied to the K input terminal of the K flip-flop (64) and obtained at the input terminal (51) is input to the JK
The synchronization signal supplied to the J input terminal of the flip-flop (64) and obtained at the input terminal (52) is supplied to the clock input terminal CK of the JK flip-flop (64). And JK
The Q output of the flip-flop (64) is supplied to a switching signal output terminal (65).

The switching signal obtained at the switching signal output terminal (65) is used to switch the movable contacts (33) and (43) of the first and second changeover switches (30) and (40) (see FIG. 1). I do. That is, when the switching signal obtained at the output terminal (65) is a low level signal "0", the movable contacts (33) and (43) are connected to the first fixed contacts (31) and (41), respectively. When the high level signal is "1", the movable contacts (33) and (43) are connected to the second fixed contacts (32) and (42), respectively.

Next, the operation of the spindle servo circuit according to the present embodiment will be described. In the spindle servo circuit, the control of the spindle motor (21) is performed by the servo control based on the wobbling frequency (control by the control circuit (13)) and the servo control based on the phase modulation data. Control (control by control circuits (16) and (20))
And selectively performed by In this case, the servo control based on the phase modulation data is performed by controlling the control signal from the control circuit (16) based on the disk rotation speed information detected from the phase modulation data and the control circuit based on the phase error information detected from the phase modulation data. The control signal from (20) is the adder (22)
, The servo control is performed with high accuracy by both control signals.

The switching between the servo control based on the wobbling frequency and the servo control based on the phase modulation data is performed in a different manner depending on whether the operation mode is the data recording operation mode or another mode such as the access mode. . That is, the switching signal generation circuit (50) is a 4-input NOR gate (5
By obtaining the product of the logical output of 6) and the logical output of the three-input NOR gate (60) by the AND gate (63), it can be seen that an error has occurred in the phase modulation data seven consecutive times. . The error detection state will be described. The parity check data supplied from the terminal (51) is synchronized with the synchronization signal supplied from the terminal (52) to generate the first, second, and third parity check data.
D flip-flops (53), (54) and (55) are sequentially set. Then, the NOR gate (5
When the parity check data indicates the occurrence of an error four consecutive times (that is, when the low level signal is “0” four consecutive times) together with the data supplied to 6), the NOR
The logic output of the gate (56) becomes the high level signal "1".
Further, when the occurrence of an error is indicated three consecutive times in total, that is, seven consecutive times, the low-level signal is also supplied to the fourth, fifth, and sixth D flip-flops (57), (58), and (59). “0” is sequentially set. Therefore, when the occurrence of an error is indicated seven times in succession, the logical output of the three-input NOR gate (60) also becomes the high level signal "1".

Here, the logical output of the 4-input NOR gate (56) is supplied to one input terminal of the AND gate (63), and the logical output of the 3-input NOR gate (60) is supplied to the AND gate (61) via the OR gate (61). When the signal supplied to the other input terminal of (63) and supplied from the terminal (62) to the OR gate (61) is a low-level signal "0", the AND gate (63) calculates the logical product of both outputs, A high-level signal "1" is obtained only when the output of both NOR gates (56) and (60) is a high-level signal "1".
Otherwise, a low level signal "0" is obtained.

Therefore, when the signal supplied from the terminal (62) to the OR gate (61) is a low-level signal "0" (that is, in the data recording mode), the parity check data is 7 bits.
An error occurs consecutively, and all of the first to sixth D flip-flops (53), (54), (55), (57), (5)
8) When the low-level signal “0” is set to (59), indicating that seven consecutive errors have occurred, together with the data supplied directly from the terminal (51) to the NOR gate (56),
The high-level signal "1" is supplied to the K input terminal of the JK flip-flop (64). Then, at this time, the low-level signal “0” is supplied from the terminal (51) to the J input terminal of the JK flip-flop (64), so that the low-level signal “0” is supplied from the Q output terminal to the terminal (65). Is obtained.
When no error occurs or when the number of consecutive errors is less than 7, the signal supplied to the J input terminal of the JK flip-flop (64) is undefined,
Since the low level signal "0" is supplied to the input terminal, a high level signal "1" is obtained from the Q output terminal to the terminal (65).

Thus, when in the data recording mode,
When the occurrence of an error is indicated seven times in succession by the parity check data, a low level signal “0” is output, and the movable contacts (3) of the first and second changeover switches (30) and (40) are output.
3) and (43) are connected to the first fixed contacts (31) and (41), respectively, and are switched to servo control by the wobbling frequency. At other times, the high level signal "1" is output, and the movable contacts (33) and (43) of the first and second changeover switches (30) and (40) are
Each of them is continuously connected to the second fixed contacts (32) and (42), and servo control based on the phase modulation data is performed.

When the signal supplied from the terminal (62) to the OR gate (61) is a high-level signal "1" (that is, in an operation mode other than data recording), the three-input NOR gate (6
Regardless of the logical output of 0), the logical output of the 4-input NOR gate (56) is obtained as it is as the logical product output of the AND gate (63).

Accordingly, four consecutive errors occur in the parity check data, and the first to third D flip-flops (5
3) Low level signal “0” is set to (54) and (55), indicating that four consecutive errors have occurred, together with the data supplied directly from the terminal (51) to the NOR gate (56). Then, the high level signal "1" is supplied to the K input terminal of the JK flip-flop (64), and the low level signal "0" is output from the Q output terminal to the terminal (65). When no error occurs or when the number of consecutive errors is less than four, the signal supplied to the J input terminal of the JK flip-flop (64) is undefined, and the low level signal is input to the K input terminal. Since the signal “0” is supplied, a high-level signal “1” is obtained from the Q output terminal to the terminal (65).

In this manner, in the operation mode other than the data recording, when the occurrence of an error is indicated four times in succession by the parity check data, the low level signal “0” is output, and the first and second changeover switches are output. The movable contacts (33) and (43) of (30) and (40) are connected to the first fixed contacts (31) and (41), respectively, and switch to servo control by the wobbling frequency. At other times, the high-level signal “1” is output, and the first and second signals are output.
The movable contacts (33) and (43) of the changeover switches (30) and (40) are kept connected to the second fixed contacts (32) and (42), respectively, and the servo control based on the phase modulation data is performed.

In this way, switching from servo control based on phase modulation data to servo control based on wobbling frequency,
The data recording operation is performed when an error occurs in the reproduced data for seven consecutive times, and when an error occurs in the reproduced data for four consecutive times in another mode such as at the time of access. Done. Therefore, during the data recording operation, the switching of the servo control is less likely to occur as compared with the access at the time of performing a track jump or the like, and once the servo control is stabilized by the servo control state based on the phase modulation data, Even when the data recording state is poor due to the wobbling of the groove formed in advance on the disc, the spindle servo is performed stably, the data is recorded by the stable magneto-optical effect, and the error rate of the recorded data is deteriorated. Can be prevented. Then, at the time of access in which a track jump or the like is performed, the servo control based on the phase modulation data is switched to the servo control based on the wobbling frequency with a small number of occurrences of the error, and the followability of the servo control becomes better than that at the time of recording.

In the above-described embodiment, the servo control is switched when seven consecutive errors occur in the recording mode.
In the other operation mode, the servo control is switched by the occurrence of four consecutive errors. However, the servo control is switched by the occurrence of four consecutive errors during access such as track jump. Alternatively, the servo control may be switched when seven consecutive errors occur in another operation mode. In this case, the control signal supplied from the central control device (25) to the switching signal generation circuit (50) may be a corresponding signal. Further, the number of occurrences of the error at which the servo control is switched may be set to another number. Further, the servo control may be switched to another method other than the servo control based on the wobbling frequency. Furthermore, the present invention is not limited to the above-described embodiment, but may take various other configurations.

〔The invention's effect〕

According to the present invention, the determination to switch from the servo control performed by detecting the synchronization signal of the information recorded in the guide groove to the servo control performed by detecting the meandering frequency of the guide groove is changed according to the operation mode. When quick control is required, for example, when starting rotation of a disc or when accessing a disk, switching is performed with a small number of errors. When stable control is required, such as during data recording, relatively many errors are generated. By switching by the number of occurrences,
Good spindle servo control according to the operation mode can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram showing a switching signal generating circuit of one embodiment, and FIG. 3 is a block diagram of a conventional switching signal generating circuit. (11) is a wobbling detection circuit, (12) and (15) are speed detection circuits, (13), (16) and (20) are control circuits, and (14)
Is a synchronization detection circuit, (18) is a phase comparator, (21) is a spindle motor, (24) is a decoder, (25) is a central control device, (30) is a first switch, and (40) is a second switch. (50) is a switching signal generation circuit, (51) is a parity check data input terminal, (52) is a synchronization signal input terminal, (62) is a recording control signal input terminal, and (65) is a switching signal output terminal. It is.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B 19/00-19/28

Claims (2)

(57) [Claims] 1. A rotation control device for rotating a disk in which address information is recorded in a guide groove meandering at a predetermined period formed on a disk in advance, the rotation control device comprising: a meandering period detecting means for detecting a predetermined period of the guide groove; First speed control means for generating a first speed control signal based on the frequency signal detected by the meandering cycle detecting means; and demodulating recording information recorded in the guide groove meandering at the predetermined cycle. A synchronization signal detecting means for detecting a synchronization signal from demodulated recording information; a second speed control means for generating a second speed control signal based on the synchronization signal detected by the synchronization signal detection means; Switching means for switching between the first speed control means and the second speed control means; a parity check means for checking the parity of the demodulated record information; and a parity check means. Switching control means for switching the switching means from the second speed control means to the first speed control means when an error of a predetermined number or more is detected, and a speed control signal selected by the switching means. The rotation control device is configured to perform a rotation drive based on the following, and change the predetermined number of times in the parity check unit according to an operation mode. 2. The rotation control device according to claim 1, wherein the change of the predetermined number of times in the parity check means according to the operation mode is made loose at the time of data recording and strict at the time of access.