JPH0572038B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a recording disk playback method, and particularly
This invention relates to a so-called high-speed playback method for intermittently reproducing information recorded on a CLV (Constant Linear Velocity) recording disk.

A so-called high-speed reproduction operation is performed to selectively reproduce information at a desired location among the recorded information on a recording disk. That is, a method is adopted in which information is read and reproduced intermittently while controlling the recording information detection point to be fast-forwarded in the radial direction of the recording disk to find the information desired by the user. A schematic block diagram of a reproducing device that performs such high-speed reproducing operation is shown in the first section.
As shown in the figure.

In the figure, reference numeral 1 denotes a recording disk, for example a digital audio disk, which is rotationally driven by a spindle motor 2. As shown in FIG. A pickup 3 is provided to read recorded information on the disk 1. A laser beam 4 for reading information is emitted from the pickup 3, and information is detected using the reflected light from the recording disk 1. This laser beam 4 becomes a recording information detection point. A feed screw 6 rotated by a motor 5 is provided to move the pick-up 3 in the radial direction of the disk, and the pick-up 3 is screwed onto the feed screw 6.

The output from the information detection point of the pickup 3 is converted into an electrical signal by the photoelectric conversion element 7 and input to the error signal generation circuit 8. This circuit 8 is configured to generate a focus error signal and a tracking error signal. The focus error signal is input to the focus control circuit 9 to control the movement of the objective lens in the pickup 3 in the direction perpendicular to the disk, thereby performing focus servo.

On the other hand, the tracking error signal is input to the tracking control circuit 10 and via the adder 11 drives the tracking actuator in the pickup. This tracking actuator finely adjusts the position of the information detection point in the disk radial direction in order to follow the recording track. Further, a pickup position control circuit 12 which receives a tracking error signal as input is provided.
Then, the DC component of the tracking error signal is detected and a drive signal corresponding to this DC level is sent to the adder 13.
is applied to the motor 5 via. The motor 5 moves the pickup 3 in the radial direction of the disk, and the position of the information detection point in that direction is roughly adjusted. Through these fine adjustments and coarse adjustments, so-called tracking control is performed in which the information detection point always accurately tracks the recording track.

A rotation speed detector 14 is provided to detect the rotation speed of the spindle motor 2, and a PLL extracts clock information from the output of the photoelectric conversion element 7.
A (phase locked loop) circuit 15 is provided, and a spindle motor control circuit 16 generates a drive signal for the spindle motor 2 using the rotation speed detection output and clock information.
Constant linear velocity control of the recording track is performed.

A demodulation circuit 17 which receives the photoelectric conversion output and clock information demodulates the digital information, and an error correction circuit 18 performs error correction. The reproduction information thus obtained is separated into left and right channel information by a left and right channel separation circuit 19, and is input to D/A (digital/analog) conversion circuits 20L and 20R. The left and right channel signals, which have become analog signals, are derived as line output signals via LPFs (low pass filters) 21L and 21R.

On the other hand, in the case of high-speed reproduction, a jump control circuit 22 is provided to perform a so-called jump operation in which the information detection point crosses the recording track. This is the drive signal for the king actuator. Further, a motor drive circuit 23 is provided, and its drive output is supplied via an adder 13 to a motor 5 serving as coarse adjustment means. The operations of the jump control circuit 22 and the motor drive circuit 23 are controlled by a microcomputer (abbreviated as microcomputer) 24, and high-speed playback operations and the like are controlled by commands from a keyboard 25. The microcomputer 24 controls the operation timing of the spindle motor control circuit 16 and the focus control circuit 9.

The operation during high-speed reproduction will be explained using FIGS. 2 to 5. In each of these figures, parts equivalent to those in FIG. 1 are designated by the same reference numerals.

First, referring to FIG. 2, there is shown an example in which the pickup 3 moves from the outer circumference of the recording disk 1 toward the inner circumference and performs intermittent high-speed reproduction.
It is assumed that the recorded information on the disk 1 is recorded sequentially from the inner circumference to the outer circumference, and the same applies hereafter. When a high-speed playback command is given from the keyboard 25 to the microcomputer 24, the operation of the tracking control circuit 10 is stopped by the command from the microcomputer 24, and at the same time, the tracking actuator is driven by the jump control circuit 22 to set the information detection point. A predetermined number of recording tracks are jumped at once (indicated by arrow a). At the same time, the motor control circuit 23 is activated instead of the pickup position control circuit 12,
Since the motor 5 is driven, the pickup 3 moves at a substantially constant speed in the direction shown by arrow b (inner circumferential direction of the disk). In this case, the tracking jump operation of the information detection point is performed almost instantaneously, but since it takes a predetermined time for the pickup 3 to move in the direction of arrow b, the tracking control circuit 10 is activated again at the end of the jump operation to perform tracking control. It will be done. Therefore, during this tracking control, the information detection point moves toward the outer periphery by a distance C while reading the recorded information. Since the information on the recording tracks existing between this distance C is read and reproduced, the user can listen to the information during this distance. The microcomputer 24 determines whether or not the recorded information is being reproduced correctly at this time based on the address information being output from the demodulation circuit 17.
If the reproduction is correct, the above-described operation is repeated. On the other hand, if the information is not being reproduced correctly, the repetition of the above-mentioned operations is stopped, tracking control is continued until the information is reproduced correctly, and then a command is given to repeat the above-mentioned operations.

The above operation is performed from the keyboard 25 to the microcomputer 2.
This is repeated while the high-speed playback command is being output to 4. If the playback sound during the above-mentioned tracking control operation period is what the user desires, the high-speed playback command is stopped and the search operation ends. I will do it.

FIG. 3 shows an example in which the pickup moves from the inner periphery of the disk to the outer periphery (in the direction of arrow b'), and the operating order of each circuit is controlled in the same manner as in FIG. 2. First, the tracking actuator is driven so that the information detection point jumps a plurality of tracks at once (indicated by arrow a), and then the tracking operation is started. Next, the pickup 3 moves as shown by arrow b', and during this time the information detection point follows the recording track and moves by a distance C to read the information. This operation is repeated.

In the examples shown in Figures 2 and 3, the amount of movement of the information detection point in the basic operation is A-C and A+C (A is the amount of movement due to the jump operation), and there is a difference in the amount of movement between the two. It turns out.

Next, referring to FIG. 4, when moving from the outer circumference of the disk toward the inner circumference (in the direction of arrow b), the disk jumps to an adjacent track for each jump operation. For example, when playing at 3x speed,
The information detection point moves from the inner circumference to the outer circumference by a distance E while performing a jump operation to adjacent tracks three times from the outer circumference to the inner circumference, and then performs tracking. During this tracking operation, the pickup moves in the direction of arrow b, so it moves by D-E in one operation (corresponding to two-track movement). Note that D is a distance equivalent to 3 tracks.

In Fig. 5, the disk is moved from the inner circumference to the outer circumference (in the direction of arrow b'), and as in the example of Fig. 4, the disk performs a jump operation three times for each track, and then performs a pickup operation while performing a tracking operation. A case of movement in the direction of arrow b' is shown.
In this example, the pickup is moved by D+E in one operation (equivalent to 4-track movement). In this way, even with the high-speed playback operation method shown in FIGS. 4 and 5, there is a difference in the amount of pickup movement. become.

In the high-speed reproduction method shown in Figs. 2 and 3 described above, the amount of displacement of the information detection point by the actuator in one jump operation is large, so the repulsive force of the tracking actuator against the displacement becomes large, and the tracking control after the jump is There may be cases where this cannot be carried out smoothly. As a result, it takes time to read the information correctly. Also, 1
Because the amount of movement during the jump operation is large, CLV (constant linear velocity) recording disks
In order to keep the linear velocity constant before and after the jump operation, it is necessary to change the rotation speed of the spindle motor, which also has the disadvantage of lengthening the information reading time.

On the other hand, in the high-speed playback method shown in Figs. 4 and 5, since the jump operation of the information detection point is controlled to repeatedly move the information detection point to adjacent tracks in sequence, the moving time and amount of movement are small. Tracking control also becomes smoother. However, the second and third
In both the formulas shown in Figures 4 and 5, the amount of movement in one movement operation (that is, the operation from the start of jump operation to the end of tracking control) is from the outer circumference to the inner circumference, and from the inner circumference. There is a difference between moving from the center to the outer periphery, resulting in a difference in moving speed.

In addition, in both types, the amount of movement of the information detection point by the tracking actuator in jump operation mode 1 (that is, the operation from the start of jump operation to the start of tracking control) is always set to a constant value, so the CLV method In the case of a recording disk, the amount of information skipped in the first jump operation mode varies depending on the direction of movement of the pick-up and the position on the disk, which may make it impossible to properly identify and search for the desired playback location. .

The present invention eliminates the difference in pick-up movement speed caused by the direction of movement during high-speed playback so that the pick-up movement speed is always constant, and the information reading interval is always constant regardless of the pick-up movement direction and the position on the disk to achieve desired playback. The purpose is to provide a playback method that can appropriately search for a location.

The reproduction method according to the present invention includes a fine adjustment means for controlling the position of the information detection point in the radial direction of the recording disk so that the information detection point determined by the emitted light of the pickup follows the track of the recording disk; A reproducing method for intermittently reproducing recorded information on a CLV recording disk using a recorded information reproducing apparatus configured to perform tracking control using coarse adjustment means for controlling the position of the pickup in the radial direction, comprising: The fine adjustment means is driven to control the information detection point to sequentially jump to an adjacent recording track a predetermined number of times, and then tracking control is performed to reproduce information for a predetermined period of time, and these jump control and tracking control are repeated. The invention is characterized in that the predetermined number of times during the jump control is controlled to be changed depending on the position and moving direction of the information detection point in the radial direction.

The present invention will be explained below using the drawings.

FIG. 6 is a block diagram of an embodiment of the present invention,
Components equivalent to those in FIG. 1 are designated by the same reference numerals, and their description will be omitted. In this example, a pick-up position detection circuit 26 is provided, and this detects the current position of the pick-up, that is, the information detection point in the disk radial direction based on the output of the rotation speed detector 14 that detects the rotation speed of the spindle motor 2. It is configured. Since information is recorded on a CLV recording disk at a constant linear velocity, it is necessary to reproduce the information while controlling the rotational speed of the spindle motor 2 according to the position of the information detection point in the radial direction of the disk. By detecting the rotational speed of the spindle motor, the current position of the information detection point can be determined.

The detection output of the pick-up position detection circuit 26 is one input to the microcomputer 24, and based on this position detection information and high-speed playback direction information from the keyboard 25, the microcomputer 24 performs one jump operation during high-speed playback. The apparatus is configured to determine the number of times the information detection point jumps to an adjacent track by the tracking actuator in the tracking mode. Further, since information for setting a high speed playback speed such as double speed/triple speed is commanded from the keyboard 25, the microcomputer 24 calculates and determines the number of track jumps using this command information as well.

FIG. 7 is a diagram for explaining the operation of the blocks in FIG. 6, and parts equivalent to those in FIGS. 1 to 6 are designated by the same reference numerals. When the keyboard 25 outputs a command for high-speed playback at 5x speed toward the inner circumference, the microcomputer 24 determines the number of track jumps required for 5x playback based on these commands and the detection output of the pickup position detection circuit 26. Calculate. When the above command is executed when the pick-up 3 is located on the outer periphery of the disk shown in the left part of FIG.
4 decides.

Once the necessary number of jumps is determined, the operations of the tracking control circuit 10 and the pickup position control circuit 12 are stopped. Instead, the jump control circuit 22 operates to drive the tracking actuator, and the information detection points are located at the arrows d ₁ to d in the figure.
Jump to adjacent tracks one after another three times as shown in d ₃ . When the three jumps are completed, the operation of the jump control circuit 22 is stopped, and tracking control is performed again by the tracking control circuit 10. During this tracking control operation, information is read and reproduced, and during this time the pickup 3 is moved in the direction of arrow b by the motor drive circuit 23.

The above operation is repeated while a high-speed playback command is issued from the keyboard 25, but once every several times, for example, once every 100 times (the track pitch of a digital audio disk is 1.6 μm, and 3 times). If the jump is repeated 100 times, the pick-up will move 200 tracks when moving from the outer circumference to the inner circumference, and the pick-up will move 0.32 mm.)
The required number of jumps is calculated and determined by the microcomputer 24 by introducing position detection information from the output of the pickup position detection circuit 26. Therefore, high-speed playback operation at a constant playback speed is possible.

This operation is repeated until the 3rd pick-up becomes the 7th pick-up.
When reaching the right side of the figure, that is, the inner circumference of the disk, the number of jumps is determined to be 5, and after 5 jumps, the information is played back and the pick-up is
The action of moving in the same direction will be repeated.
In this case as well, position detection is performed once every 100 operations to determine the number of jumps, but in the inner circumference the information is reproduced by moving 400 tracks, that is, 0.64 mm. The change in rotational speed for this 0.64 mm movement is 2.5% at the inner circumference and 1.1% at the outer circumference, and variations in playback speed are well tolerated.

The above explanation is based on the case where the pick-up moves from the outer circumference to the inner circumference, but when moving from the inner circumference to the outer circumference, the number of jumps is similarly calculated according to the position of the pick-up, and it always moves at a constant speed. High-speed playback is performed.

In the above embodiments, a digital audio disk playback device was described. However, as long as it is an information recording disk on which information is recorded in a spiral manner, it is possible to use not only an optical pickup but also a capacitive pickup or a mechanical pickup. It is possible to implement even if the

Further, in the above embodiment, the motor drive circuit 23 is provided in order to move the pickup at a higher speed than in the normal playback state. If a pick-up position control circuit 12 and a pick-up moving motor 5 that can control the position of the pick-up are used, the motor drive circuit 2
3 is not necessary.

In the above embodiment, a pick-up with a focus actuator and a tracking actuator was used, but a pick-up that uses a galvanometer mirror to follow the information detection point in the tracking direction, or a pick-up that uses a galvanometer mirror to track the information detection point in the tracking direction, or a pick-up that uses a galvano mirror to track the information detection point in the tracking direction, or a pick-up that tracks the entire pick-up, may be used. It is also possible to use a method that follows the .

In addition, in the above embodiment, the pick-up position is detected by detecting the rotation speed of the spindle motor, but it is also possible to detect the pick-up position by detecting the rotation angle of the pick-up moving motor or by using a potentiometer that is linked to the pick-up. It may be the method used.

In the above embodiment, the frequency of pickup position detection was set to once every 100 operations, but the detection frequency may be changed depending on the playback speed, and the detection frequency may be changed between the inner and outer circumferences, or the detection frequency may be changed depending on the playback speed. As long as this is allowed to a certain extent, it may be roughly divided into three parts: outer periphery, middle periphery, and inner periphery.

Furthermore, in the above embodiment, the playback speed was kept constant, but depending on the microcomputer program, the speed could be changed during playback, the information reading time could be changed, etc.
It is possible to read only the necessary information and immediately repeat the jump operation without reading unnecessary information.

As described above, in the high-speed playback method for CLV recording disks according to the present invention, the number of adjacent track jumps in one jump operation mode of the information detection point of the pick-up can be changed depending on the pick-up movement direction, and the number of adjacent track jumps can be changed depending on the pick-up position. Since it is configured so that it can be changed, the information reading interval can be kept approximately constant regardless of the moving direction of the pickup and the position on the disk, and the information can always be reproduced at a constant speed. In addition, jump movement (jump operation mode) of the information detection point is achieved by repeatedly jumping to adjacent tracks, which reduces the time required for movement and reduces the time when information is lost during high-speed playback. Can be shortened. Furthermore, since the lengths of information missing sections can be made equal, appropriate information searches are always possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional recording disk playback device, FIGS. 2 to 5 are diagrams each explaining the high-speed playback operation of the device in FIG. 1, and FIG. 6 is a block diagram of an embodiment of the present invention. , FIG. 7 is a diagram explaining the operation of the block in FIG. 6. Explanation of symbols of main parts, 1...recording disk,
3...Pickup, 5...Pickup position control motor, 10...Tracking control circuit, 12
... Pickup position control circuit, 22 ... Jump control circuit, 23 ... Motor drive circuit, 24 ...
Microcomputer, 25...Keyboard, 26...Pickup position detection circuit.

Claims (1)

[Scope of Claims] 1. Fine adjustment means for controlling the position of the information detection point in the radial direction of the recording disk so that the information detection point determined by the emitted light of the pickup follows the track of the recording disk, and CLV using a recorded information reproducing apparatus which performs tracking control using coarse adjustment means for controlling the position of the pickup in the radial direction.
A reproduction method for intermittently reproducing recorded information on a recording disk, wherein the fine adjustment means is driven to control the information detection point to sequentially jump to an adjacent recording track a predetermined number of times, and then the information is reproduced for a predetermined period of time. The jump control and the tracking control are performed repeatedly, and the predetermined number of times during the jump control is controlled to be changed depending on the position and movement direction of the information detection point in the radial direction. A playback method characterized by: