JPH06203494A - Track jump method for clv disk player and measuring method for linear velocity of clv disk - Google Patents

Abstract

PURPOSE:To always and accurately perform the jump of only the required number of tracks by calculating the number of tracks to be traversed by a pickup by using a present address, a target address and a linear velocity. CONSTITUTION:In a step 401, the number of tracks F from an innermost circumference to the present address is calculated with the equation I by using the present address and the detected linear velocity T. In the step 402, the number of tracks G from the innermost circumference to the target address is calculated with the equation I similarly by using the target address and the detected linear velocity T. In the step 403, a difference between the calculated numbers of tracks F and G is taken, and that is made the number of tracks to jump from the present address. Thus, the number of times repeating the track jump are reduced remarkably, and a search processing time is shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a track jump method for a CLV disk player (CLV: Constant Linear Velocity) and a method for measuring the linear speed of a CLV disk which can be used in this track jump method.

[0002]

2. Description of the Related Art In a CD (compact disc), in order to maximize the recording density, the rotational speed on the outer peripheral side is made lower than the rotational speed on the inner peripheral side of the disk to keep the linear velocity constant.
It is an LV disc. Also LD (laser disk)
However, in order to increase the recording density, a CLV disc is also used. Further, in these disc players, when the head of a music piece is brought or the pickup is brought to a desired position, a track jump is performed to jump from a track having the current pickup to an inner or outer target track.

[0003]

In the CLV disc standard, the linear velocity is 1.2 to 1.4 (m / sec).
An error within the range of is recognized. Therefore, even if the difference between the target address and the current address is the same number of addresses, the number of tracks to jump must be increased for a disk with a high linear velocity compared to a disk with a low linear velocity.

Therefore, the above 1.2-1.4 (m / se
For each disc with a significantly different linear velocity such as c), the standard linear velocity is used to determine the number of tracks to jump, and when this number of tracks is made to jump, the pickup reaches after the jump. The track and the target track can differ significantly. Therefore, the track jump is repeated in the same procedure many times until the target track is reached, and the search process takes time.

In view of this point, an object of the present invention is to provide a track jump method capable of always performing exactly the required number of tracks even for CLV disks having different linear velocities. To do. A further object of the present invention is to provide a linear velocity measuring method that can be used when performing this track jump.

[0006]

In order to solve the above-mentioned problems, the present invention, in a track jump method of a CLV disk player, measures the linear velocity of a disk to be reproduced, and at the time of performing the track jump, present address and purpose. The number of tracks that the pickup should traverse is calculated using the address and the linear velocity, and the pickup is made to jump by the calculated number of tracks.

Alternatively, instead of calculating the number of jump tracks by calculation, the present invention stores the number of tracks in the first linear velocity disc and the correction coefficient in the second linear velocity disc in correspondence with a plurality of addresses. Table is prepared in advance, the linear velocity is first measured for the disc to be reproduced, and when the track jump is performed, the table is used to determine the number of tracks at the current address from the current address and the linear velocity of the disc being reproduced. The number of tracks of the target address is calculated from the target address and the linear velocity, and the number of jump tracks is obtained from these to jump the pickup.

Further, in the present invention, as a method for measuring the linear velocity of the CLV disk which can be used for each of the above-mentioned track jump methods, the pickup is jumped from the current address to the CLV disk by a predetermined number of tracks. The linear velocity of the CLV disk is calculated using the address after the jump, the current address, and the number of tracks jumped.

[0009]

【Example】

[Embodiment 1] An example in which the present invention is applied to a CD player and the number of jump tracks is calculated using a calculation formula will be described with reference to FIGS.
Will be explained. FIG. 1 is a flowchart showing a reproducing process of a CD player, FIG. 2 is a flowchart showing an entire process of the CD player, FIG. 3 is a flowchart showing a method of detecting a linear velocity in FIG. 1, and FIG. It is a flowchart which shows the track number calculation method in 1. The processing shown in these flowcharts is performed by the microcomputer.

In the overall processing of the CD player shown in FIG. 2, initialization is performed in step 201 when the power is turned on, and initialization is performed for the inside of the microcomputer and the attached devices. Next, at step 202, it is judged if a disc is set in the player. If the disc is not set, the process without the disc or the process at the time of stop is performed in step 203, and if the disc is set, the process proceeds to step 204.

The reproduction process of step 204 is performed as shown in FIG. The reproduction process starts with step 10.
1, 102, and 103, the TOC (T is written with the data peculiar to the disk set in step 103.
(able of contents) is read. When the TOC reading is completed, in the next cycle, step 10
From 2 to step 104, the linear velocity is detected. The detection of the linear velocity in step 104 will be described later in detail. When the linear velocity of the disc is detected, the initials of the disc are all finished.

When the initial of the disk is completed, in the subsequent cycles, the routine proceeds from step 101 to step 105, and it is judged at step 105 whether or not a command for searching, that is, a track jump is issued. If no search command is issued, the routine proceeds to step 106, where trace processing is carried out, track jump is not carried out, and normal reproduction is carried out subsequently.

If a search command is issued, step 105
To step 107, the number of tracks to jump to is calculated in step 107. The calculation of the number of tracks will be described in detail later. Then, after this, in step 108, track jump processing is performed. Here, the pickup is jumped by the number of calculated tracks.

The method of detecting the linear velocity and the method of calculating the number of jump tracks in the above description will be described. First, a method of calculating the number of jump tracks will be described.
In the case of the CD disc of this example, the address A portion B from the innermost circumference
The number of tracks up to the second C frame is represented by the following [Equation 1].

[0015]

[Equation 1]

From this [Equation 1], the linear velocity v is expressed by the following [Equation 2].

[0017]

[Equation 2]

Next, regarding the linear velocity detecting method of this example,
This will be described with reference to FIG. This linear velocity detecting method shows the content of step 104 performed after step 102 of FIG. When the linear velocity is detected, the process proceeds from step 301 to step 302, and the current address D is stored. Ideally, the current address D is 0 frame, but in actuality, it may deviate from 0 frame, so this current address is stored. Next, in step 303, a predetermined jump process is performed,
The pickup is made to jump a predetermined number N of tracks.

When this jump process is completed, the process proceeds from steps 301 and 304 to 305 in the subsequent cycles.
If the reading of the subcode of the frame on the track after the jump is completed, the address E of the frame is stored in step 306. Next step 30
In step 7, the difference between the stored current address D and the jumped address E is calculated, and this difference is taken as the total number of frames to be jumped (A minutes B seconds C frames), and this frame number and the jumped track number N are used. Then, the linear velocity T is calculated by [Equation 2]. Note that [Equation 2] is an expression for calculating the linear velocity T with reference to the innermost 0 frame, whereas in this description, since the current address D slightly deviated from the 0 frame is used, the jump is performed. Although an error occurs in the number of tracks, this error is practically negligible.

Next, a method of calculating the number of tracks to be jumped when performing a track jump when a search command is issued to the CLV disc being reproduced will be described with reference to FIG. The calculation of the number of tracks indicates the content of step 107 performed after step 105 of FIG. In step 401, the number F of tracks from the innermost circumference to the current address is calculated by [Equation 1] using the current address and the detected linear velocity T. In step 402,
Similarly, using the target address and the detected linear velocity T, the number of tracks G from the innermost circumference to the target address is calculated by [Equation 1]
To calculate. In step 403, the difference between the calculated track numbers F and G is calculated and used as the track number to jump from the current address.

According to the method described above, the linear velocity of the CLV disk is detected by a simple method, and the number of tracks to be jumped is calculated by the formula using this linear velocity. On the other hand, the jump is always performed to the track extremely close to the target address.
Therefore, the number of times the track jump is repeated is significantly reduced, and the search processing time is shortened.

[Second Embodiment] In the first embodiment described above,
Although the linear velocity is detected and the number of tracks to jump is calculated by a formula that uses this linear velocity, a table is prepared instead of the formula, and the number of tracks to jump is calculated based on this table and the detected linear velocity. It is also possible to calculate. An example of this table will be described using the following [Table 1].

[0023]

[Table 1]

In Table 1, the first column lists a plurality of addresses H1 to Hn selected at appropriate intervals. In the second column, in the case of a CLV disk having a linear velocity of 1.2, the track numbers J1 to Jn from the innermost circumference corresponding to the respective addresses in the first column to the addresses are listed. In the third column, in the case of a CLV disk having a linear velocity of 1.4, the number of tracks from the innermost circumference corresponding to each address in the first column to that address is shown as a ratio of the number of tracks in the second column. The correction coefficients K1 to Kn are listed.

Next, a method of calculating the number of jump tracks using this table will be described. First, the linear velocity T of the disc to be reproduced is measured as in the first embodiment. When performing a track jump, the current address is read first. The address closest to the present address is selected from the table, and the correction coefficient for the linear velocity of T is calculated from the correction coefficient for the address at the linear velocity of 1.4 by proportional distribution.

The correction coefficient for the linear velocity T is 1.
Although it does not change proportionally between 2 and 1.4, proportional distribution is used to simplify the process. It has been confirmed that this method is practically sufficient. Then, the obtained correction coefficient is multiplied by the number of tracks of the linear velocity 1.2 at that address to obtain the number of tracks of the current address of the linear velocity T.

Next, also for the target address, the address closest to the target address is selected from the table, and the correction coefficient for the linear velocity T is calculated by proportional distribution from the correction coefficient for the linear velocity of 1.4 at that address. To do. Then, the obtained correction coefficient is multiplied by the number of tracks of the linear velocity 1.2 at the corresponding address in the table to obtain the number of tracks of the target address of the linear velocity T.

Finally, the difference between the track number of the target address and the track number of the current address obtained from the above calculation is calculated, and the pickup is made to jump by setting that value as the jumping track number. Also in this embodiment,
The linear velocity of the CLV disc is detected by a simple method, and the number of tracks to be jumped is calculated by using this linear velocity with a simple table. A jump is made to a nearby track. Therefore, the search time can be shortened.

Although the first and second embodiments have been described with reference to the CD, the C other than the CD such as the LD is used.
The present invention is also applicable to LV discs. In this case, the mathematical formulas and the like are appropriately changed. Also,
The use of the linear velocity detection of the present invention is not limited to the track jump described above.
It can also be used independently for inspection of the linear velocity of the LV disc.

[0030]

As described above, the track jump method in the CLV disk player of the present invention always causes the CLV disk having different linear velocities to perform the jump exactly the required number of tracks. You can Further, the method for measuring the linear velocity of the CLV disk of the present invention can easily measure the linear velocity of the disk without using a device for detecting the rotational speed of the spindle or a device for detecting the position of the pickup.

[Brief description of drawings]

FIG. 1 is a flowchart showing a reproduction process of a CD player according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing the overall processing of the CD player of the embodiment of the present invention.

FIG. 3 is a flowchart showing a method for detecting the linear velocity in FIG.

4 is a flowchart showing a method for calculating the number of tracks in FIG.

Claims (3)

[Claims] 1. In a track jump method for a CLV disc player, the linear velocity of a disc to be reproduced is measured, and when the track jump is performed, the current address, the target address, and the linear velocity are used to determine the number of tracks that the pickup should traverse. A track jump method for a CLV disc player, which comprises calculating and jumping the pickup by the calculated number of tracks. 2. A track jump method for a CLV disc player, wherein, for a plurality of addresses, the number of tracks from the innermost circumference to each address is set to a first disc whose linear velocity is known and a second disc whose linear velocity is known. The number of tracks itself was stored for each address for the first linear velocity disc, and the correction coefficient was stored for each address for the second linear velocity disc. Prepare a table in advance, measure the linear velocity of the disc to be played back first, and use the current address and the linear velocity of the playing disc to perform the track jump from the innermost circumference of the current address from the table. Calculate the number of tracks and use the target address and linear velocity to find the track from the innermost track of the current address from the table. A track jump method for a CLV disc player, wherein the number of tracks is calculated, the number of tracks at the difference between the number of tracks at the current address and the number of tracks at the target address is calculated, and the pickup is made to jump by this number of tracks. 3. A method for measuring the linear velocity of a CLV disk, wherein a pickup jumps a predetermined number of tracks from a current address with respect to a CLV disk to be reproduced, the address after this jump is read, and the current address and the jump. A method of measuring the linear velocity of a CLV disc, which uses the subsequent address and the number of tracks to be jumped to calculate the linear velocity of the CLV disc.