JP2000048379A - Searching method for disk player - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a moving operation efficient and to make a searching speed high by calculating the number of tracks from a current position to a target position after calculating the number of frames of one round at the current position when the target position becomes to be in a movable state and also calculating the remaining number of frames and setting the number of tracks to be jumped in accordance with the remaining number of frames. SOLUTION: The focusing control operation of an optical pickup 4 is performed to obtain a focusing and when it is detected that a disk 1 is mounted on a turntable 2, the rotational driving operation of a spindle motor 3 by a spindle motor control circuit 12 is started. When a changeover signal for performing a reproducing operation is outputted from a computer device 9, the rotational driving operation of the motor 3 is performed so that the rotation of the disk 1 becomes a rotational speed whose angular velocity is constant by the control operation of a system control circuit 10 and the read-out operation of a signal from the disk 1 and the processing operation of the signal are performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a search method for a disk player configured to read out a signal recorded on a disk by an optical pickup.

[0002]

2. Description of the Related Art A disk player which performs a reproducing operation by reading out a signal from a disk on which information data such as music is recorded by a digital signal using an optical pickup has become widespread. One of them is a CD player.

As is well known, a disc used in such a CD player is called a sub-coding signal in which one block is completed at a period of 1/75 second in addition to a main data signal such as music information. A sub data signal is recorded. Such subcoding signals are P, Q to W
The P channel includes position index information indicating the position of the beginning of the song, and the Q channel includes the absolute elapsed time from the start of the signal track, the elapsed time for each song, and the Q channel. Position index information indicating a song number or the like is included.

[0004] Therefore, the CD player can perform an operation of detecting a position where a desired song or the like is recorded by using the position index information and performing a reproducing operation, that is, an operation called a search. Have been.
Such a search operation is performed by moving the optical pickup in the radial direction of the disc. Such a movement operation is an operation of moving the main body of the optical pickup at a high speed to near the target position, that is, a pickup feeding operation. And an operation of displacing the objective lens constituting the optical pickup, that is, a track jump operation.

Recently, a CD called a CD-ROM for reproducing a data signal used for a computer, not a sound signal of music or the like, is reproduced.
-Disk players called ROM players are widespread. Since such a CD-ROM player is required to perform a high-speed signal reading operation, an increasing number of products perform a disk rotation control operation not at a constant linear velocity but at a constant angular velocity.

[0006]

The search operation in the disc player is performed by calculating the number of tracks from the absolute time of the current position and the absolute time of the target position to the target position, and using the optical pickup in accordance with the number of tracks. It is performed by moving the CD-ROM player, and a high-speed search operation is required in the CD-ROM player. In order to perform the search operation at high speed, it is necessary to move the main body of the optical pickup to a position near the target position at high speed. However, when such a movement operation is performed, the light beam emitted from the optical pickup is The position may be in front of the target track or overrun the target position.

After the movement operation of the main body of the optical pickup is completed, an operation of moving the light beam to a target position by a track jump operation of the objective lens is performed.
In the recent track jump operation, since the number of jumps that can be jumped by one track jump can be freely selected, one time after the movement operation of the main body of the optical pickup is completed. It is possible to move to the target position by the jump operation.

However, as the rotation speed of the disk becomes higher, the light beam moves to the target position by the track jump operation, and when the signal reading operation is started, after the light beam passes the position where the target signal is recorded, The probability of signal readout increases, in which case it is necessary to return the position of the light beam by another track jump operation, which causes a problem that the search speed is reduced.

It is an object of the present invention to provide a disc player search method which solves the above problem.

[0010]

According to the present invention, when the target position becomes movable due to the track jump of the objective lens, the number N of frames in one round at the current position is obtained, and then the number of tracks from the current position to the target position is obtained. The number of surplus frames M is obtained, and the number of tracks T to be jumped is determined according to the number of surplus frames.

[0011]

FIG. 1 is a flowchart showing a search method according to the present invention, and FIG. 2 is a block circuit diagram of a disc player according to the present invention.

In FIG. 2, reference numeral 1 denotes a disk on which a signal is recorded at a constant linear velocity, and 2 denotes a turntable on which the disk 1 is mounted and which drives the disk 1 to rotate. It is configured to be driven. Reference numeral 4 denotes an optical pickup for reading out a signal recorded on the disk 1 by irradiating a light beam to a signal surface of the disk 1. The optical pickup 4 includes an objective lens, a photodetector, etc., and a pickup feed motor. The main body is configured to be moved in the radial direction of the disc 1 by the rotation of the disc (not shown).

Reference numeral 5 denotes an RF signal amplifier circuit for amplifying an RF signal obtained from a photodetector incorporated in the optical pickup 4 and shaping the waveform, and 6 denotes a signal obtained via the RF signal amplifier circuit 5. The optical pickup 4 performs a focusing control operation for focusing a light beam of the optical pickup 4 on a signal surface of the disk 1 and a tracking control operation for causing the light beam to follow a signal track on the signal surface. The pickup control circuit performs a control operation of a track jump by a displacement operation of the objective lens. The operation is performed by controlling a movement of the objective lens.

Reference numeral 7 denotes a digital signal processing circuit which receives a signal output from the RF signal amplifier circuit 5 and performs demodulation of various signals, and 8 denotes a digital signal processed by the digital signal processing circuit 7. Is a signal reproducing circuit to which a data signal is input, and is configured to output a data signal to the computer device 9.

A system control circuit 10 receives a signal demodulated by the digital signal processing circuit 7 and performs various operation controls in accordance with a switching signal output from the computer device 9. It is configured. Reference numeral 11 denotes a pickup feed control circuit that controls the rotation of the pickup feed motor to control the feed operation in the radial direction of the main body constituting the optical pickup 4, and the operation is controlled by the system control circuit 10. It is configured as follows.

Reference numeral 12 denotes a spindle motor control circuit for controlling the rotation of the spindle motor 3. The operation of the spindle motor 3 is controlled by a motor control signal output from the system control circuit 10. 13
Is a track jump control circuit for controlling the number of tracks jumped by the track jump of the objective lens by the pickup control circuit 6, and the operation thereof is controlled by the system control circuit 10.

The disk player according to the present invention is configured as described above, and the operation will be described next. When the disc 1 is inserted into a storage section provided in a disc player, the disc 1 is placed on the turntable 2 and a focusing control operation for focusing a light beam emitted from the optical pickup 4 on a signal surface. Is performed.

When the focusing control operation of the optical pickup 4 is performed and the focus is obtained, it is detected that the disc 1 is mounted on the turntable 2. When such a detection operation is performed, the rotation driving operation of the spindle motor 3 by the spindle motor control circuit 12 is started. Such a rotation driving operation of the spindle motor 3 is performed by detecting and utilizing a synchronization signal recorded on the disk 1. However, such operation is a well-known technique, and a description thereof will be omitted. When such an operation is being performed, a focusing control operation and a tracking control operation by the pickup control circuit 6 are performed,
An operation of reading disk data recorded on the disk 1 is performed.

When a switching signal for performing a reproducing operation is output from the computer device 9, the system control circuit 10
With the control operation described above, the spindle motor 3 is driven to rotate so that the disk 1 has a constant angular velocity, and a signal reading operation from the disk 1 and a signal processing operation are performed.

The signal read by the optical pickup 4 is input to an RF signal amplifier circuit 5 where it is amplified and shaped, and applied to a digital signal processing circuit 7. After the signal input to the digital signal processing circuit 7 is subjected to digital signal processing, its data signal component is demodulated and input to the signal reproduction circuit 8. The data signal input to the signal reproduction circuit 8 is output to the computer device 9 through an output terminal, and the computer device 9 performs a predetermined signal processing operation.

As described above, the signal reading operation in this embodiment is performed. Next, the search method which is the gist of the present invention will be described with reference to the flowchart shown in FIG.

When a switching signal for reading out a desired signal from the signals recorded on the disk 1 is output from the computer device 9, the system control circuit 10 enters a state of performing a search operation.

In the search operation, first, the distance for moving the main body of the optical pickup 4 in the radial direction of the disk 1 is determined from the current position and the target position, and the main body is controlled by the pickup feed control circuit 11 by the set value. It is moved by the control operation. When the moving operation of the main body of the optical pickup 4 by such an operation is completed, the position of the light beam is at a position where it can be moved to the target position by one track jump operation of the objective lens.

When the light beam moves to such a position, the signal recorded on the disk 1 is read out,
The radius of the current position is determined from the current position and the linear velocity of the disk (this linear velocity differs from 1.2 m to 1.4 m for a CD disk, but can be determined by a known method) ( Step A). When the radius of the current position is obtained in step A, the number N of frames in one round at the position is obtained (step B). The number of frames between the absolute time of the current position and the absolute time of the target position is obtained, and the number of frames is divided by the number N of frames obtained in step B to obtain the number of tracks T to the target position and the number of remaining frames. M is obtained (step C).

When the number of tracks T to the target position and the number of remaining frames M are obtained in step C, it is determined whether or not the target position is outside the current position (step D). If it is determined in step D that the target position is outside, it is determined whether or not the number of remaining frames M obtained in step C is M> N / P (step E). Here, P is the ratio of the time required for one rotation of the disk 1 to the time required for jumping, and is a value greater than 1. For example, if the rotation speed of the disk is 6000 revolutions / minute, the time required for one round is 0.01 second, and if the time required for jumping is 0.005 seconds, P in this case is 2. . Therefore, under this condition,
The determination in step E is M> N / 2. That is,
It is determined whether or not the number of remaining frames is larger than the number of frames on the half circumference of the disk 1. From now on,
It is performed based on this condition. In step E, M> N
/ 2, that is, when the remaining frame number M, which is the number of frames existing from the position of the light beam moved by the jump operation to the target position, is larger than N / 2, Track jump is performed (step F). That is, since the target position comes to the position of the light beam after performing the T track jump, it is possible to start the reading operation of the desired data recorded at the target position by starting the signal reading operation as it is. I can do it.

In step E, when it is determined that M> N / 2 is not satisfied, that is, the remaining frame number M, which is the number of frames existing from the position of the light beam moved by the jump operation to the target position, is N / N. If it is smaller than 2, jump T-1 tracks (step G). That is, when the signal read operation is started by performing the T track jump, the target position passes through the position of the light beam when the signal read operation is started.
Therefore, in this case, by moving the position of the light beam to a track located just before the target track by one track, a read operation of desired data recorded at the target position can be started.

The operation when the target position is on the outer peripheral side from the current position is performed as described above. Next, the operation when the target position is on the inner peripheral side from the current position will be described. If it is determined in step D that the target position is not on the outer peripheral side, that is, on the inner peripheral side, a T + 1 track jump is performed regardless of the number M of remaining frames (step H). That is, in this case, the position where the T-track jump, which is the number of tracks obtained by the operation of Step C, has already passed the target position, and therefore it is necessary to make the track jump one track more than that position. is there. By performing such an operation, a read operation of desired data recorded at a target position can be started immediately.

In this embodiment, the case where a disk in which signals are recorded from the inner periphery to the outer periphery is used has been described. However, signals are recorded from the outer periphery to the inner periphery. When a disc is used, the opposite operation is performed. Further, in this embodiment, when the track number T obtained in step C is 1, the jump number in step G becomes 0, and in this case, the jump operation is not performed and the signal Is started. Then, in step C, if the obtained track number T is 0, the jump number in step G becomes −1,
In this case, a signal read operation is started after a jump operation of one track is performed in the reverse direction.

[0029]

According to the present invention, when the target position becomes movable due to the track jump of the objective lens, the number of frames N around the current position is obtained, and then the number of tracks from the current position to the target position is calculated. Since the number of surplus frames M is obtained as well as the number of tracks T to jump according to the number of surplus frames, the desired signal of the light beam after the end of the moving operation of the optical pickup main body is recorded. The moving operation to the position where it is can be performed efficiently, and as a result, the search speed can be increased.

Further, the present invention sets the number of tracks jumped by the track jump in accordance with the relationship between the target position and the current position, so that the search operation can be performed efficiently. Have.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a search method of the present invention.

FIG. 2 is a block circuit diagram of a disc player according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disc 3 Spindle motor 4 Optical pickup 6 Pickup control circuit 10 System control circuit 11 Pickup feed control circuit 13 Track jump control circuit

Claims (3)

[Claims] 1. A target position can be searched for by a movement operation of an optical pickup main body and a track jump operation of an objective lens incorporated in the optical pickup, and the disk is kept at a constant angular velocity. In a disk player configured to be driven to rotate, when the target position is movable from the current position by one track jump of the objective lens, the number of frames N in one round at the current position is determined. The number of tracks T from the position to the target position is obtained, and the number of remaining frames M is obtained. When the target position is on the outer peripheral side, the number of tracks T to jump is set according to the number of remaining frames. How to search for a disc player. 2. When the ratio of the time required for one rotation of a disk to the time required for reading a signal by a track jump is P (P is larger than 1), T track jump is performed when M> N / P, 2. The method according to claim 1, wherein when M> N / P is not satisfied, a T-1 track jump is performed.
Search method. 3. A target position can be searched by a moving operation of an optical pickup main body and a track jumping operation of an objective lens incorporated in the optical pickup, and the disk is kept at a constant angular velocity. In a disk player configured to be driven to rotate, when the target position is movable from the current position by one track jump of the objective lens, the number of frames N in one round at the current position is determined. Find the number of tracks T from the position to the target position,
A disc player search method, wherein the number of track jumps is set to T + 1 track when the target position is on the inner circumference side.