JPH0731890B2 - Search method for disc player - Google Patents

Description

TECHNICAL FIELD The present invention relates to a search method in a disc player.

2. Description of the Related Art In a conventional disc player search method, as shown in FIG. 6, by comparing a current address with a target address and repeating a jump operation of a distance set based on the difference, A search (hereinafter referred to as a search) was being performed. That is, first, when the current address and the target address are compared at a point, the current address is smaller than the target address, so a so-called long jump operation of moving the pickup by a relatively long distance in one jump operation is performed in the FWD direction (inner circumference of the disc). To outer circumference). By repeating this jump operation several times, the information detection point of the pickup reaches the point. At this point, comparing the current address with the target address, this time, the current address is larger than the target address, so that a so-called short jump operation with a shorter jump distance than the long jump is performed in the REV direction (from the outer circumference of the jump to the inner circumference direction). To do. By repeating this jump operation several times, the information detection point of the pickup reaches the point. At this point, when the current address and the target address are compared again, this time the current address is smaller than the target address, so the so-called one-track jump in which the information detection point of the pickup jumps one recording track of the disc in the FWD direction. To do. By repeating this one-track jump several times, the information detection point of the pickup reaches the target address (point), and the target address can be searched.

As described above, in the conventional search method in the disc player, the jump direction is set and the jump distance is shortened based on the magnitude relationship between the current address and the target address so that the target address is converged. Despite the large difference between the target address and the current address due to a malfunction of the decoder that decodes the address information, a misreading of the data, an error in the recorded data of the disc, etc., the 1-track jump operation is performed and it takes a long time until the search is completed. It had the drawback of being time consuming.

SUMMARY OF THE INVENTION The present invention has been made to eliminate the above-mentioned drawbacks of the conventional ones, and a quick search operation can be performed even if a malfunction of a decoder, a misreading of data, an error of recorded data on a disc, or the like occurs. The purpose is to provide a search.

The search method in the disc player according to the present invention is
A search method in a disk player equipped with a pickup for reading recorded information from a recording disk, the method comprising: a long track jump step of causing a long track jump in the direction of a target position according to a search command and until the target position is exceeded. And a short track jump step in which the pickup makes a short track jump in the opposite direction to the long track jump until the pickup reaches the target position after the execution of the long track jump step, and a predetermined time during execution of the short track jump step. When the pickup does not reach the target position even after the passage of, the return stroke is returned to the execution of the long track jump stroke.

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

FIG. 1 is a block diagram showing an example of an optical recording disk reproducing apparatus to which the search method according to the present invention is applied. In the figure, a laser beam emitted from, for example, a laser diode 2 in a pickup 1 passes through a prism 3, a tracking mirror 4, an objective lens 5, and the like to become spot light (information detection point), which is a recording track (pit) of a disc 6. (Row) 7 is illuminated. The reflected light of the spot light passes through the objective lens 5, the tracking mirror 4, and the prism 3 and is incident on a so-called four-divided detector 8 including a photodiode or the like built in the pickup 1. The total output of the 4-division detector 8 is the read RF signal.
It is supplied to the demodulator 10 via the RF amplifier 9,
After being demodulated by, the data is supplied to the data extraction circuit 11. In the data extraction circuit 11, address information is extracted from the demodulation output,
The address information is supplied to the controller 12.

Each output of the 4-division detector 8 is also supplied to the tracking error signal generation circuit 13. As a method of generating the tracking error signal, there is a so-called 1-beam method, a 3-beam method, or the like, and the 1-beam method includes a so-called push-pull method, a heterodyne method, or the like. The tracking error signal generated by the tracking error signal generation circuit 13 is
As shown in FIG. 2, it has a so-called S-curve characteristic of zero crossing at the center of the recording track 7, and a drive coil for the tracking mirror 4 via a mirror drive circuit 14.
By being supplied to 15, the mirror 4 is driven to rotate.

Reference numeral 16 denotes a slider motor that mounts the pickup 1 and drives a slider (not shown) that is movable in the disk radial direction. The motor 16 is driven and controlled by a motor drive circuit 17. The motor drive circuit 17 detects the tilt angle of the tracking mirror 4 based on the output of the mirror drive circuit 14, and the slider motor 16 causes the slider motor 16 to move in the disk radial direction so that the tilt angle is zero. Position control.
The mirror drive circuit 14 and the motor control circuit 17 are also drive-controlled by a drive signal issued from the controller 12. The track pulse generation circuit 18 generates one pulse each time the spot light crosses the recording track 7 based on the tracking error signal shown in FIG. 2 when the pickup 1 moves in the disk radial direction, and sends it to the controller 12. . The controller 12 is supplied with an address search command generated by an operation by a user and data indicating a target address from an operation unit (not shown). The controller 12 is formed by a microcomputer including a processor, ROM, RAM, timer and the like. This controller
At 12, the processor is pre-stored in ROM and operates according to a program based on the flowchart of FIG.

Next, the operation of the processor in the controller 12 will be described with reference to the sequence diagrams of FIGS. 4 and 5 and along the flowchart of FIG.

On a recording disc, for example, a so-called compact disc, information indicating the absolute time from the innermost disc to the current position, the information indicating the absolute time from the innermost disc to the head of each song, and the like are recorded. Now, if an address search command is issued when the information detection point, that is, the spot light of the pickup 1 is located at point (a), the processor causes the timer to start a time-dependent operation and the data extraction circuit 11 to operate.
The current address is read from the address information extracted in (see FIG. 1) (step 1), and the obtained current address and target address are compared (step 2).
When it is determined that the distance between the two addresses is larger than a certain value, that is, the target address is far, the number of tracks between the current address and the target address is calculated (step 3). The number of tracks is calculated based on the absolute time of each address, the disk rotation speed, the track pitch, and the like. Next, the processor sets the number N of tracks obtained by this calculation as the number N'of tracks to be counted, and then moves the pickup 1 in the target address direction, in the FWD direction in the example of FIG. 3 (step 4). At this time, the number of tracks N is a certain value n
When it is determined that the number of tracks is larger, a value obtained by subtracting the constant value m from the number of tracks N may be set as the number of tracks N'to be counted. By this subtraction, when the pickup 1 moves, the spot light of the pickup 1 can be prevented from overshooting the target address due to a calculation error of the number of tracks, a feed overshoot, or the like. Instead of subtracting the constant value m from the track number N, the track number N is set to a constant value l (l <1) smaller than 1.
You may multiply by.

The processor counts the number of track pulses generated from the track pulse generation circuit 18 (see FIG. 1) at the same time as the pickup 1 is moved, and determines whether or not the count number has reached the track number N '( When the count number does not reach the track number N ', it is determined whether or not m seconds have elapsed from the time when the address search command was issued (step 6). Repeat step 5 only if not. When it is determined that the count number has reached the track number N ', the processor stops the movement of the pickup 1 (step 7). As a result, the spot light reaches the point (b).

The processor reads the current address again at point (b), compares the current address with the target address (steps 1 and 2), and moves to step 8 when the distance between both addresses is less than a certain value. Compare the current address with the target address. If it is determined in step 8 that the current address is greater than the target address, the processor moves to step 9 and revs a 100-track jump for jumping the spot light by a distance of 100 tracks.
Direction, and then it is judged whether or not m seconds have elapsed since the address search command was issued (step 10).
In the example shown in the figure, the current address is smaller than the target address, so the process moves to step 13 through step 12 and jumps 100 tracks in the FWD direction. After this, the processor determines whether or not m seconds have elapsed from the time when the address search command was issued, based on the output data of the timer (step 1
3) Only when m seconds have not elapsed, repeat 100 track jumps in the FWD direction until it is determined in step 11 that the current address is larger than the target address. As a result, the spot light reaches point (c). Subsequently, the processor makes a 10-track jump until the current address exceeds the target address while determining whether or not m seconds have elapsed from the time when the address search command was issued, based on the output data of the timer.
Perform in the REV direction (step 14, step 15, step 1
6). When the current address exceeds the target address due to this 10-track jump in the REV direction, the processor determines the current address by checking whether or not m seconds have elapsed from the time when the address search command was issued, based on the output data of the timer. Perform a one-track jump in the FWD direction until the address matches or exceeds the target address (step 1
7, step 18, step 19). That is, after the spot light reaches the point (b), the processor converges the spot light of the pickup 1 to the target address by gradually reducing the jump distance according to the result of the comparison of the current address and the target address. is there.

Here, when the spot light is moved to point (d) by 100 track jumps as shown in FIG.
It is assumed that the current address is determined to be larger than the target address even though the erroneous data is read at the point and the position of the spot light is located on the inner side of the target track. Then, the processor makes a 10-track jump in the REV direction (step 15), and the spot light moves to point (e). When correct data is read at this point (e), it is determined that the current address is smaller than the target address, and the processor attempts to perform a one-track jump in the FWD direction until the current address matches the target address or exceeds the target address. . However, in this case, since the search time becomes abnormally long, for example, when the spot light reaches point (f), the elapsed time from the generation of the address search command becomes m seconds, and in step 19, the address search command is output according to the output data of the timer. When it is determined that m seconds have elapsed from the time of occurrence of the occurrence, the processor determines whether or not the number of search repetitions has reached n (step 20), and only when the number of search repetitions is less than n, step 1 The subsequent execution is restarted. As a result, the processor reads the current address at point (f), sets the number of tracks N'according to the difference from the target address, moves the pickup 1 in the FWD direction, and at the same time counts the number of track pulses. When it reaches N ', the movement of the pickup is stopped. As a result, the spot light is (g) near the target address.
Reach the point. After this, the processor proceeds to step 8 to move the spot light to the point (h) by the 100 track jump and then move the spot light to the point (i) by the 10 track jump as in the case of FIG. After this, the processor converges the spot light to the target address by one-track jump.

As described above, according to the search method in the disc player of the present invention, the long jump operation (100 track jump) is first executed until the pickup goes over the target address position in response to the search command.
In the direction opposite to the jump direction of such a long jump,
Short jump operation (10 or 1 track jump) until the pickup reaches the above target address position
In the search operation of executing the above step, if the pickup does not reach the target address position even if a predetermined time elapses during the execution of the short jump operation, the execution of the long jump operation is resumed. In this way, the track jump movement operation in which the distance movement is small due to erroneous reading of data is not repeated for a long time, and a quick search can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of an optical recording disk reproducing apparatus to which the search method according to the present invention is applied, FIG. 2 is a diagram showing the relationship between recording tracks and tracking error signals, and FIG. 3 is according to the present invention. Flowcharts showing the procedure of the search method in the disc player, FIGS. 4 and 5
FIG. 6 is a sequence diagram showing a search operation according to the present invention.
The figure is a sequence diagram showing a conventional search operation. Description of main parts 1 Pickup 4 Tracking mirror 6 Recording disk 11 Data extraction circuit 12 Controller 13 Tracking error signal generation circuit 18 Track pulse generation circuit

Claims (1)

[Claims] 1. A search method in a disc player having a pickup for reading recorded information from a recording disc, wherein a long track jump is performed in a direction of a target position of the pickup in response to a search command and until the target position is exceeded. A long track jump stroke, and a short track jump stroke that causes a short track jump in the opposite direction of the long track jump until the pickup reaches the target position after the execution of the long track jump stroke, and a short track jump stroke. A method for searching in a disc player, comprising: a return step of returning to the execution of the long track jump step if the pickup does not reach the target position even after a predetermined time has elapsed during execution.