JP3022189B2 - Disc playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for reproducing a disc record. More specifically, the present invention relates to an apparatus having a compatible function of reproducing discs having different recording densities.

[0002]

2. Description of the Related Art A disk drive (CAV disk) of a constant angular velocity system in which a recording signal such as a video signal is reproduced by controlling the rotation so that the angular velocity of the disk becomes constant, and the linear velocity of the disk become constant. As described above, there is provided a disk drive (CLV disk) of a constant linear velocity system which reproduces a recording signal such as a video signal by controlling the rotation. For example, in the case of an NTSC disk on which an NTSC television signal is recorded, the rotation of the CAV disk is controlled so as to have an angular velocity of about 30 [rotation / second], and the rotation of the CLV disk is about 10.75 [m / second]. The rotation is controlled so as to be the speed.

In order to provide playback control and random access control, there is a disk record in which an address signal is bi-phase modulated and multiplexed and recorded on a recording signal such as a video signal. This address signal indicates that the disc has a standard speed ±
Reading is possible when the rotation is performed at about 10%. Here, the standard speed is an angular velocity of 30 [rotation / second] for the current CAV disk, and a linear velocity of 10.75 [m / second] for the CLV disk of the current recording density. .

[0004]

Along with the development of a semiconductor laser for an optical pickup having a short wavelength, a disk having a high recording density and a reproducing apparatus for the disk have been developed. It is desired that the reproducing apparatus has a compatible function capable of reproducing not only a high recording density disk but also a conventional recording density (standard density) disk.

The standard linear velocity of a standard density CLV disc on which an NTSC television signal is recorded is 1 as described above.
The standard linear velocity of a high-density CLV disk on which an NTSC television signal is recorded for a long time is 7.3 [m / sec], whereas the standard linear velocity is 0.75 [m / sec]. . For this reason, standard density CLV discs and high density CLV
In a compatible device that reproduces both disks, it is necessary to quickly determine the recording density of the set disk so that the set disk can be controlled to rotate at an optimum linear velocity according to the recording density. The high-recording-density disc includes not only a long-term NTSC disc but also a high-density disc on which MUSE or base-band television signals are recorded.

In the case of a CAV disk, addresses at the same position in the radial direction are different between a high recording density disk and a standard recording density disk. For this reason, in a compatible device for reproducing both the standard density CAV disk and the high density CAV disk, it is necessary to quickly determine the recording density of the set disk in order to perform random access control or the like quickly. There is. SUMMARY OF THE INVENTION An object of the present invention is to provide a disc reproducing apparatus capable of quickly determining the recording density and the like of a set disc.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a disk reproducing apparatus for controlling the rotation of each of disks having different recording densities, each recording a main signal in which an address signal is multiplexed, and reproducing the disks. Address detecting means for generating an address detection output when the address signal is detected on the way, angular velocity detecting means for detecting angular velocity of the disk and outputting angular velocity information, and at a predetermined position in the disk radial direction at the initial stage of disk rotation start A disc reproducing apparatus comprising a movement control means for positioning a pickup and a discriminating means for discriminating a recording density of the disc based on angular velocity information when an address detection output is generated.

In the above, the angular velocity detecting means may be configured to compare the detected angular velocity with a predetermined threshold and output information as to whether the velocity is higher or lower than the threshold as angular velocity information. In that case, the pickup is positioned at the lead-in portion on the inner peripheral side of the disk at the beginning of the rotation start of the disk, and when the angular velocity information is information indicating that it is faster than the threshold value, the standard density disk is used, and the information indicating that it is slow is used. In some cases, it may be configured to determine that the disc is a high density disc.

The present invention also relates to a disk reproducing apparatus for controlling the rotation of each of the disks having different recording densities by recording a main signal in which an address signal is multiplexed, and reproducing the disks during the rotation of the disk. The angular velocity is a predetermined angular velocity for CAV control (constant angular velocity control) (for example, 30
[Rotation / sec]), an angular velocity detection means for generating an angular velocity detection output, an address detection means for detecting the address signal and outputting address information, and A disc reproducing apparatus comprising a movement control means for positioning the pickup at an intermediate position in the radial direction and a discrimination means for discriminating the recording density of the disc based on address information when an angular velocity detection output is generated. is there.

In the above, the address detecting means may be configured so that the detected address signal is compared with a predetermined threshold value and information indicating whether the address signal is smaller or larger than the threshold value is output as address information. Here, if the value is smaller than the threshold value, the disc is determined to be a CAV standard density disc, and if the value is larger than the threshold value, it is determined to be a CAV method high density disc. Further, after this determination, the pickup may be moved to a program start position in the disk radial direction.

[0011]

According to the present invention, when a disk is set and reproduction is commanded, the pickup is moved to a predetermined position in the radial direction (for example,
It is positioned at the innermost radius of 55 [mm], and the rotation of the disk is started. When an address signal is detected during the rotation start, an address detection output is generated, and at that timing, the recording density of the disk is determined based on the angular velocity information. For example, when the angular velocity information is given by comparison with a predetermined threshold value, and a pickup is set in the lead-in portion, it is determined that the disk is a standard density disk if it is faster than the threshold value and a high recording density disk if it is slower. .

According to the present invention, when a disk is set and reproduction is commanded, the pickup is positioned at a radially intermediate position (eg, a position with a radius of 100 mm) in the recording area, and the disk is rotated. Is started. When the angular velocity reaches a predetermined angular velocity for CAV control during rotation start, an angular velocity detection output is generated, and at that timing, the recording density of the disk is determined based on the address information.
For example, if the address information given by comparison with the predetermined threshold value is smaller than the threshold value, it is determined that the disc is a CAV standard density disc, and if it is larger, it is a CAV high recording density disc.

[0013]

Embodiments of the present invention will be described below. In the first embodiment shown below, a standard density CLV disc (standard density disc) on which NTSC television signals are recorded for a standard time and a high density CLV disc (standard density disc) on which NTSC television signals are recorded for a long time are used. High density disc).

For a standard density CLV disc, 10.7
Address detection is possible within a range of 5 [m / sec] ± 10 [%]. Considering that the program area of the standard density disc has a radius of 55 [mm] to 145 [mm], the linear velocity is approximately 30 [rotation / sec] to 11 [rotation / sec].
Second] (see the broken line in FIG. 2).

On the other hand, for a high density CLV disc,
Address detection is possible within a range of 3 [m / sec] ± 10 [%]. The linear velocity is such that the program area of the high-density disc has a radius of 55 mm to 14
Considering the range of 5 [mm], this corresponds to an angular velocity of approximately 21 [rotation / sec] to 8 [rotation / sec] (see the solid line in FIG. 2).

Therefore, when the pickup is positioned at a position (lead-in portion) with a radius of 55 mm (lead-in portion), rotation control is started, and reading out of a reproduction signal is started, a high-density CLV disk is set in the apparatus. If there is 2
When the rotation rises around 1 [revolution / sec], the address signal is detected, and an address detection output should be generated. On the other hand, if a standard density CLV disc (or CAV disc) is set in this apparatus, 30
An address signal should be detected and an address detection output should be generated only after the rotation has risen to around [rotation / sec]. In the first embodiment, this is used to determine the recording density of the disk.

Referring to FIG. 1, the circuit configuration of the present apparatus and the operation of the first embodiment will be described. When the disc D is set in the apparatus and the reproduction is commanded, the pickup 2 moves the pickup 2 from the center of the disc by 55 [m
m] (lead-in portion). The movement to this position is detected by the switch 3.
Note that a laser device having a short wavelength (670 [nm]) is used for the pickup 2 and the beam spot diameter is smaller than the conventional laser wavelength (780 [nm]). However, it is also possible to reproduce a high-density disc.

When the pickup 2 is moved to the above position, focus servo, tracking servo and feed servo are performed by the pickup servo circuit 1,
Reading of the recording signal of the disk D is started. Also,
The drive of the disk motor is started by the disk servo circuit 4, and the disk D starts to rotate toward a rotation speed of 30 [rotation / second]. The disk servo circuit 4
Performs the servo by comparing the phase of the output of the FG circuit 8 for detecting the rotation speed of the disk motor M with the reference signal at the time of starting and accessing the disk. In addition, during reproduction of the recording signal in which the synchronization signal is correctly generated, servo is performed by comparing the phase of the horizontal synchronization signal with the reference signal.

A reproduction signal output from the pickup 2 is input to an FM demodulation circuit 5, converted into an original NTSC video signal, and output to the outside. The output of the FM demodulation circuit 5 is also input to a synchronization detection circuit 6 and an address signal detection circuit 7. The synchronization detection circuit 6 detects a horizontal synchronization signal of the NTSC video signal, and the horizontal synchronization signal is sent to the disk servo circuit 4 to be used for controlling the rotation of the disk motor M during reproduction as described above.

On the other hand, in the address signal detecting circuit 7, NT
Address signals multiplexed within the vertical blanking period of the SC signal are detected. This address signal indicates that the rotation speed of the video disk record is within ± 10 of the standard speed.
It can be detected when it is within the range of [%]. That is, when the disk is rotated at a speed in this range, the PLL of the address signal detection circuit 7 is locked, and the address signal can be read. The address signal detected in this way is sent to the pickup servo circuit 1 and the disc discrimination circuit 10. In the pickup servo circuit 1,
Based on the address signal, the beginning of the program part,
Random access control is performed.

When an address signal is sent from the address signal detection circuit 7 at the time of startup, the disk determination circuit 10 refers to the disk rotation state input from the rotation speed detection circuit 9 to determine the recording density of the disk. You. For example, if the rotation speed is around 21 [revolutions / sec], and therefore lower than 25 [revolutions / sec], it is determined that a high density disc is set. Also, the rotation speed is around 30 [rotation / sec],
If it is higher than [rev / sec], it is determined that the standard density disc is set. As described above, the rotation speed detection circuit 9 determines whether the rotation speed is lower or higher than the threshold value of 25 [rotation / second] based on the output of the FG circuit 8 for detecting the rotation speed of the disk motor M. The result is sent to the discrimination circuit 10.

The output of the disc discriminating circuit 10 is sent to a pickup servo circuit 1 and a disc servo circuit 4 to be used for pickup control and disc motor control, respectively. As a result, reproduction suitable for the set disk is performed. For example, when it is determined that the disc is a standard density CLV disc, the linear velocity is 10.75.
Rotation control is performed so as to be [m / sec], and an access operation is also performed in the case of a CLV disk with a standard density. If it is determined that the disc is a high recording density CLV disc, the rotation is controlled so that the linear velocity becomes 7.3 [m / sec], and the access operation is performed in the case of the high recording density CLV disc. The operation is performed.

In the first embodiment, the standard time NTS
The case where a standard density CLV disc on which a C signal is recorded and a high recording density CLV disc on which a long NTSC signal is recorded is described, but the present invention is not limited to the above. That is, the present invention can be applied to a compatible device for reproducing disks having different densities. For example, MU
The present invention is also applicable to a high-density disc on which an SE television signal or a baseband television signal is recorded. Also, the CAV disk and the CLV disk can be similarly identified by setting the detection radius position of the address signal to an appropriate position, for example, a radius of 100 [mm]. In this case, two thresholds for the angular velocity information are required.

Next, a method of distinguishing between a standard density CAV disc and a high recording density CAV disc (second embodiment)
Will be described. The description of the same parts as in the first embodiment is omitted. Standard density CAV disk and high recording density C
Since the track pitch is different from that of the AV disk, the address at the same radial position in the recording area is different. In the second embodiment, the two are identified by utilizing this fact.

When the disk D is set in the apparatus and the reproduction is commanded, the pickup servo circuit 1 moves the pickup 2 to a position 100 mm from the center of the disk (an intermediate portion in the recording area). When the pickup 2 is moved to the above position and the disk D is started to rotate and its angular velocity reaches 30 [rotation / sec], an angular velocity detection output is generated from the rotational speed detection circuit 9.

In the disk discriminating circuit 10, when the angular velocity detecting output is sent from the rotational speed detecting circuit 9, the address information from the address signal detecting circuit 7 is discriminated at that timing. That is, when the address detected by the address signal detection circuit (address at a position of radius 100 [mm]) is smaller than a predetermined address (threshold), the CAV standard density disc is used. When the detected address is larger than the predetermined address. Is determined to be a CAV type high density disc. The detected address may be compared with a predetermined address (threshold) by the address signal detection circuit 7 and the result may be sent to the disk determination circuit 10.

After the above determination, the disk determination circuit 10 instructs the disk servo circuit 4 to stop the acceleration. Further, the pickup 2 is moved to the program start position (about 56 [m
m]). Also, the equalizer 11 is instructed to switch its characteristics so as to match the recording density. When the disc is discriminated when the pickup 2 is set at a position of a radius of 100 [mm], when the disc is discriminated as a CLV disc (first discrimination before discrimination by the method of the second embodiment). (When determined by the method of the embodiment)
Since the speed at the program start position is insufficient and the acceleration needs to be continued, the acceleration stop command is not immediately issued to the disk servo circuit 4.

[0028]

As described above, according to the present invention, the recording density of the disk can be promptly determined based on the angular velocity at the time of start-up when the address signal is detected, so that the reproduction can be promptly shifted to the optimum speed. Further, in the present invention, the recording density of the CAV disk can be quickly determined on the basis of the address at the time when the speed reaches the angular speed of the CAV control method at the time of startup, so that the reproduction at the optimum speed can be promptly shifted.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a main part of a circuit configuration of an apparatus according to an embodiment.

FIG. 2 is a characteristic diagram showing a rotational speed of a disk with respect to a disk radius.

Claims (6)

(57) [Claims] 1. A disk reproducing apparatus for reproducing a disk having different recording densities formed by recording a main signal in which an address signal is multiplexed, and detecting the address signal during the rotation start of the disk. Address detection means for generating an address detection output at times, angular velocity detection means for detecting angular velocity of the disk and outputting angular velocity information, and movement control means for positioning the pickup at a predetermined position in the radial direction of the disk at the beginning of rotation of the disk. Discriminating means for discriminating the recording density of the disc based on the angular velocity information at the time when the address detection output is generated. 2. The disc reproducing apparatus according to claim 1, wherein the angular velocity detecting means compares the detected angular velocity with a predetermined threshold and outputs information indicating whether the detected angular velocity is higher or lower than the threshold as angular velocity information. 3. The disk drive according to claim 2, wherein the predetermined position of the pickup is a lead-in portion on the inner peripheral side of the disk, and the discriminating means is a standard density disk when the angular velocity information is higher than the threshold value. A disc reproducing device that determines that the disc is a high-density disc if the angular velocity information indicates that the disc is slow. 4. A disk reproducing apparatus for reproducing a disk having different recording densities formed by recording a main signal in which address signals are multiplexed and controlling the angular velocity of the disk during the start of rotation of the disk by CAV control. Angular velocity detecting means for generating an angular velocity detection output when a predetermined angular velocity is reached; address detecting means for detecting the address signal and outputting address information; and a radius in a recording area of the disk at the initial stage of rotation start of the disk. A disc reproducing apparatus comprising: movement control means for positioning a pickup at an intermediate position in a direction; and discrimination means for discriminating a recording density of the disc based on address information when an angular velocity detection output is generated. 5. The discriminating means according to claim 4, wherein the address detecting means compares the detected address signal with a predetermined threshold value and outputs information as to whether the value is smaller or larger than the threshold value as address information. Is a disc reproducing apparatus that determines that the address information is smaller than the threshold value, the disc is a CAV standard density disc, and that the address information is larger than the threshold value is a CAV disc. 6. The disc reproducing apparatus according to claim 5, wherein the movement control means moves the pickup to a program start position in a disc radial direction after the discrimination by the discrimination means.