JPH01185887A - Disk reproducing device - Google Patents

Abstract

PURPOSE:To realize track jump whose accuracy is high without providing a special linear velocity measuring device by providing an arithmetic operation processing means which calculates corrected linear velocity data from linear velocity data based on a formula and writes the data in a memory circuit. CONSTITUTION:When a pickup movement command b is given to a first arithmetic operation means 4a, the means 4a calculates the jump track number N' of a pickup. After that, a control means 4b generates a control signal C based on the jump track number N' and sends it to a pickup movement mechanism 3. Besides, a second arithmetic operation means 4d calculates the corrected linear velocity data V based on the track number N' obtained from the means 4a, a track number N obtained from a count means 4c and the linear velocity data V' stored in the linear velocity memory circuit 5, writes this data in the circuit 5 and sends it to the mechanism 3. As the result of that, the pickup 2 arrives at an aimed position more precisely and more quickly than first jump operation.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a disc playback device such as a compact disc device.

(Prior Art) In a compact disc device (hereinafter referred to as CD), as shown in Fig. 1, a disc (1) is rotated at a constant linear velocity by a disc motor (6). The signal recorded on the pick-up transfer machine! 11 (3) and moves in the radial direction of the disk. Further, the operation of the pickup transfer device $11 (3) and the disk motor (6) is controlled by a pickup controller (4).

When moving the pickup (2) from the current position to the target point quickly in the CD, the pickup transfer mechanism (
3) causes the pickup (2) to jump by an appropriate number of tracks (Japanese Unexamined Patent Application Publication No. 1983-1999)
-217273 (C11B21108]), the number of tracks to which the pickup (2) should jump is determined by the track pitch of the disk, the radius of the track at the target point, as described below.
It can be calculated from the signal recording linear velocity, etc.

The jumping operation of the pickup (2) continues until the pickup reaches the target position, and the jump width gradually converges to zero.

(Problem to be solved) However, the CD standard allows variations in the linear velocity in the range of 1.2 to 1.4 m/s when recording signals on the disc, and the linear velocity varies depending on the disc. Speeds vary. Therefore, when playing the signal, the pickup (2)
In order to quickly reach the desired playback position, it is essential to accurately measure the linear velocity when calculating the number of jump tracks. However, providing a special linear velocity measuring device for this purpose not only complicates the device configuration, but also
There was a problem in that time was wasted to measure the linear velocity.

SUMMARY OF THE INVENTION An object of the present invention is to provide a disc playback device that can realize highly accurate track jumps without providing a special linear velocity measuring device.

(Means for Solving the Problems) In the disc playback device according to the present invention, a memory circuit (5) in which linear velocity data representing linear velocity at the time of signal recording is to be stored is connected to the pickup controller (4). be done.

Further, as shown in FIG. 2, the pickup controller (4) calculates the number of tracks N' to which the pickup should jump based on the pickup transfer command B and the linear velocity V' stored in the memory circuit (5). A first arithmetic processing means (4a), a control means (4b) for creating a control signal C for the pickup transport mechanism (3) based on the number N' of jump tracks, and a control means (4b) for counting the actual number of jump tracks accompanying the movement of the pickup. (4c), the number N' of tracks obtained from the first arithmetic processing means, the number N of tracks obtained from the counting means after the pickup is moved,
and linear velocity data V stored in the memory circuit (5)
', v=v'・N'/N . . . A second arithmetic processing means (4) calculates corrected linear velocity data (2) based on the formula (2) and writes the data into a linear velocity memory circuit (5).
d).

(Function) When the pickup transfer command B is issued to the first arithmetic processing means (4a), the arithmetic processing means executes the linear velocity memory circuit (4a).
5) The linear velocity data V' stored in step 5 is read out, and the number N' of jump tracks of the pickup is calculated from the address information of the target position included in the pickup transfer command B and the linear velocity data V'.

After that, the control means (4b) controls the jump track number N.
A control signal C is created based on ', and sent to the pick-up transfer machine 1 (3). This result 1. Pickup (2)
first moves by a distance corresponding to the number of jump tracks N' (hereinafter, this operation is referred to as a jump operation),
The pickup controller (4) detects the address of the signal playback position at that time from the playback signal after the movement, and based on the deviation address between the address and the address information of the pickup transfer command B, the pickup controller (4) moves the pickup transfer mechanism (
3) and finally move the pickup (2) to the target position (hereinafter, this operation is referred to as positioning operation).

The counting means (4c) counts the number of tracks N that the pickup (2) actually jumped from the start of movement to the completion of movement.
count.

Further, the second arithmetic processing means (4d) inputs the number of tracks N' obtained from the first arithmetic processing means (4a), the number N of tracks obtained from the counting means (4c), and the linear velocity memory circuit (5). From the stored linear velocity data ``2'', corrected linear velocity data V is calculated by the equation ``2'', and the data is written into the linear velocity memory circuit (5).

As described below, the formula corrects the linear velocity based on the error between the estimated number of jump tracks N' derived from the linear velocity data stored in memory and the true number N of jump tracks controlled by the pickup controller. This is an approximate formula for

The corrected linear velocity data V calculated by formula (2) is written into the linear velocity memory circuit (5).

Thereafter, when a second pickup transfer command is issued to the pickup controller (4), the first arithmetic processing means (4a) reads out the corrected linear velocity data ■ stored in the linear velocity memory circuit (5) and , the number of jump tracks of the pickup is calculated from the address information included in the pickup transfer command B and the corrected linear velocity data V.

Thereafter, the control means (4b) creates a control signal C based on the number of jump tracks, and the pickup transfer mechanism (
3). As a result, the pickup (2) approaches the target point more accurately than the first jump operation,
The subsequent positioning operations quickly reach the target point.

(Effects of the Invention) In the disc playback device according to the present invention, when a plurality of pickup transfer commands are issued, the second and subsequent pickup jump operations are performed based on the corrected linear velocity data. A highly accurate track jump is realized. Further, since the linear velocity data is corrected based on the results of the first track jump operation, there is no need to equip a special linear velocity measuring device.

(Example) FIG. 1 shows an example in which the disc reproducing apparatus according to the present invention is implemented on a CD.

The disk (1) is driven to rotate at a constant linear velocity by a disk motor (6). The pickup (2>) is linked to a pickup transfer mechanism (3) connected to a pickup controller (4) to control the track jumping operation and subsequent positioning operation.

The signal S0 read out by the pickup (2) is processed by a well-known circuit consisting of a preamplifier (8), an EFM demodulation circuit (9), an error correction circuit (10), a D/A converter (11), and an audio circuit (12). The signal goes through the playback system and is output to the speaker. The output S1 of the Brian Pook 8) is connected to the pickup controller (4).

A linear velocity memory circuit (5) is connected to the pickup controller (4), and a system controller (7) for controlling CD modes and the like is linked thereto. Note that a standard linear velocity is initially set in the linear velocity memory circuit (5).

When an operation signal A for a jump operation is sent from the operation panel to the system controller (7), the system controller (7) converts the operation signal A into a pickup transfer command C and sends it to the pickup controller (4). . The pickup controller (4) further creates a control signal C based on the pickup transfer command and supplies it to the pickup transfer mechanism (3).

Further, the pickup controller (4) sends a servo signal to the disk motor (6) to control the rotational speed of the disk (1).

The system controller (7) sends back various data E such as address information during signal reproduction to the display on the front panel.

The pickup controller (4) is composed of a microprocessor and has the functions shown in FIG. 2 as described above.

A procedure for calculating the number of jump tracks expressed by the following equation 0 is set in the first arithmetic processing means (4a).

Here, R is the radius of the innermost circumference of the signal surface, N is the number of tracks starting from the innermost track, T is address information on the disk signal surface, that is, time starting from the innermost circumference of the disk, and p
is the track pitch, and ■ is the linear velocity.

The second arithmetic processing means (4d) also stores the number N' of tracks obtained from the first arithmetic processing means (4a), the number N of tracks obtained from the counting means (4c), and a linear velocity memory circuit (5). Formula v=v' ・N to calculate corrected linear velocity data ■ from linear velocity data V' stored in
'/N (0 formula) is set.

Incidentally, the equation (2) is derived as follows.

The true linear velocity is ■, and the estimated linear velocity before moving the pickup is V.
′, the address (time) of the target point is T, and the address (time) before the pick-up movement is T′, then the true number of trucks to the target point N and the trucks N′ calculated from v′ are as follows. is expressed in

If we take the ratio of both equations, perform Tiller expansion on this, and ignore the infinitesimal term, we obtain equation (2).

Therefore, it can be seen that the linear velocity can be corrected using equation (2).

Next, the operation of the pickup controller will be explained along the flowchart of FIG.

When the pickup transfer command B is received from the system controller (13), linear velocity data V' is first read from the linear velocity memory circuit (14), and then the number of jump tracks N' of the pickup is calculated based on the above formula 0. .

After that, the control signal C is based on the jump track number N'.
and send it to the pickup transfer mechanism (15).
As a result, the pickup is moved from the innermost circumferential position toward the target position, and is finally set at the target position.

The number N of jump tracks from when the pickup starts moving until it reaches the target position is counted 16).

After that, the corrected linear velocity ■ is calculated using the above formula (17)
be done.

Finally, the modified linear velocity (2) is written into the linear velocity memory circuit, and the stored data is updated.

Thereafter, when a second pickup transfer command is issued to the pickup controller, the jump operation and positioning operation of the pickup are performed based on the corrected linear velocity (2) stored in the linear velocity memory circuit.

Therefore, before moving the pickup, the linear velocity memory circuit (5
) Even if there is an error in the linear velocity initially set for
As the pickup moves for the second time, the linear velocity is corrected, and based on this corrected linear velocity, the second and subsequent jump operations and positioning operations are performed accurately.

It should be noted that the configuration of each part of the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made within the technical scope of the claims.

For example, the linear velocity memory circuit (5) is provided with a storage section for two types of linear velocities i' and Vi-,' obtained by the past two pickup movements, and a correction line used as the basis for the next pickup movement. When setting the speed Vi, if the formula V1=(Vi'+Vi-+'')/2 is used, errors in counting the number of jump tracks during pickup movement, etc. are smoothed out, and a more accurate corrected linear velocity can be obtained. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a disc playback device according to the present invention;
Figure 2 is a functional block diagram of the pickup controller.
FIG. 3 is a flowchart. (1)...Disk (2)...Pickup (3>...Pickup transport mechanism <4)...Pickup controller <5)...Linear velocity memory circuit 74 Pickup controller Fig. 9

Claims (1)

[Scope of Claims] [1] A pickup (2) for reproducing signals from a disk (1) on which signals have been recorded at a constant linear velocity, and a pickup for moving and positioning the pickup (2) in the radial direction of the disk. In a disc playback device equipped with a transfer mechanism (3) and a pickup controller (4) that controls the pickup transfer mechanism (3) based on a pickup movement command, linear velocity data is stored in the pickup controller (4). The pickup controller (4) calculates the number of tracks N' to which the pickup should jump based on the pickup transfer command B and the linear velocity V' in the memory circuit (5). 1 arithmetic processing means and a control signal C to the pickup transfer mechanism (3) based on the jump track number N'.
means for counting the actual number of jump tracks accompanying the movement of the pickup, the number N' of tracks obtained from the first calculation processing means, the number N of tracks obtained from the counting means after the movement of the pickup, and the linear velocity. A second calculation process of calculating corrected linear velocity data V from the linear velocity data V' in the memory circuit (5) based on the formula V=V'・N'/N and writing the data into the memory circuit (5). A disc playback device comprising: means.