JPH05159489A - Access control device for disk player - Google Patents

Abstract

PURPOSE:To obtain a access control device capable of executing a stable accessing operation. CONSTITUTION:When the accessing operation is executed, a difference in track numbers between a specified address and a current address is detected by a detection circuit 42 and the accessing operation is done by this difference. Then, the resulted difference in track numbers between the current address and the specified address is detected by the detection circuit 42, a compensation coefficient is calculated by a compensation coefficient calculation circuit 41 using this difference and from then on, the accessing operation is executed by multiplying the difference in track numbers with the compensation coefficient.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc reproducing apparatus such as a CD player, a laser disc player (LD) and a CD-ROM drive.

[0002]

2. Description of the Related Art In general, a CD reproducing device has a function of cuing a music piece and the like, and is required to feed at high speed and stably. FIG. 5 is a flowchart showing a conventional high-speed access method. The difference in the number of tracks is calculated from the time difference between the current position and the access destination (12), and if the difference is small, it is converged by the track jump (18). Is large, that is, when it is far away, the pickup carriage is driven by the feed motor (10) (1
4), the track crossing pulse (TE
By counting (15) S pulses) and sending them by the track difference at high speed, the target position can be sent at high speed. Such a technique is disclosed in, for example, Japanese Patent Laid-Open No. 58-1665.
No. 66 (G11B21 / 08).

And when it is driven by a motor,
The goal is to get close to the target position, and the final convergence is performed by track jump. If the target position is not reached by one motor drive, it will be repeated many times.

FIG. 4 is a block diagram of the tracking servo system, the feed servo system, and the TES pulse generation. The signal output from the pickup (1) is generated by the tracking error signal generation circuit (2) and the tracking error signal is generated at zero volts. It is pulsed by the comparator (11) to generate a TES pulse of 1 track = 1 pulse.

The tracking error signal drives the tracking coil (6) via the phase compensation circuit (3) and the drive circuit (5). The track jump is performed by applying a signal from the jump pulse generation circuit (4) to the tracking actuator.

In the normal normal operation, the feed system phase-compensates the drive voltage of the tracking actuator (7) and drives the feed motor (10) via the drive circuit (9). When the feed motor is forcibly driven, a predetermined operation can be performed by applying a signal from the feed pulse generation circuit (8) to the feed motor.

[0007]

By the way, the above-mentioned TE
When counting S pulses, when there are missing pulses or noise in the pulses, the position may deviate greatly from the expected feed position, and if high-speed feed is repeated twice or three times, the purpose is Convergence near the position will be delayed.

This occurs every time the user issues an access command, and the access operation is always slow.

Further, since the tracking error signal of the TES pulse is detected as a zero-cross, the disk has a low RF signal level, the pulse is missing due to noise near the zero volt of the tracking error signal, and the pulse has noise. Can happen easily.

The present invention solves the above-mentioned drawbacks and proposes an access control method capable of performing a stable access operation.

[0011]

According to the present invention, at the time of high-speed feed, when it comes to a stop far before the target position, the feed amount when the next access command is received is set to be a little larger, and conversely, the target position is set. If you have jumped considerably, the feature is that the feed amount is set a little smaller next time and the feed amount for the next access is corrected from the previous feed amount.

[0012]

By the above, the next access method is modified from the previous access, and the disc is always sent in the optimum manner, so that the access operation is stabilized.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1, 2 and 3 are flow charts showing an embodiment of the present invention.

First, a block diagram is shown in FIG. In FIG. 1, (1) is a pickup, (4) is a jump pulse generation circuit, (8) is a feed pulse generation circuit, and (44).
Is a current address detection circuit, (43) is a designated address circuit for the operator to designate a desired address, (42) is a track number difference detection circuit for detecting the number of tracks between the current address and the designated address, (41) Is a correction coefficient calculation circuit, which is a circuit for setting the correction coefficient and multiplying it.

Next, the operation will be described with reference to FIGS. First, when an access command is received, a track number difference detection circuit (4) is used to determine how many tracks are apart from the time difference between the current position and the access destination, and the track number difference (M).
It is calculated in 2) (12).

When the difference in the number of tracks is small, it is converged by repeating the track jump (18), but when it is large, the convergence is slow in the track jump, so that the pickup carriage is driven by the motor (1).
4).

As the movement amount at this time, the TES pulse output when crossing the tracks is counted (15) and moved by the difference in the number of tracks calculated previously (16).

Normally, in the case of an ideal feed, it reaches the vicinity of the access destination by one feed, and then it is converged by a track jump (18), but as described above, TES.
If the pulse is scattered and it has not reached the access destination in the first feed, the feed amount (M) for the next access
In order to correct (19), the correction coefficient calculation circuit (41) calculates the correction coefficient α (23).

As shown in FIG. 3, the calculation method is to correct the next feed amount to be positive when the stop is considerably before the access destination (26), and conversely, when it is considerably jumped. The correction coefficient α is determined so as to perform negative correction (25).

From the next access, a value obtained by multiplying the calculated track number difference (M) by the correction coefficient α is set as the movement amount (19). If you remove the disc, the coefficient α
Are reset to their default values.

[0021]

According to the present invention, even if there are variations in the RF signal level due to the cutting of the disc, scratches on the disc surface, etc., the following access method is modified from the previous access, and the access method according to the disc to be used can be obtained. Since it can be corrected so that a stable access method can always be realized.

[Brief description of drawings]

FIG. 1 shows a block diagram of the present invention.

FIG. 2 is a flowchart showing an embodiment of an access control method of the present invention.

FIG. 3 is a flowchart showing a correction coefficient calculation method.

FIG. 4 Tracking, feed servo system, and TES
The block diagram which shows pulse generation.

FIG. 5 is a flowchart showing an example of a conventional access control method.

[Explanation of symbols]

 1 Pickup 4 Jump pulse generation circuit 8 Feed pulse generation circuit 41 Correction coefficient calculation circuit 42 Track number difference detection circuit 43 Designated address circuit 44 Current address detection circuit

Claims (1)

[Claims] 1. Pickup means for reproducing a signal from a recorded disc, current address detecting means for detecting an address currently being reproduced, address specifying means for allowing an operator to specify a desired address, Means for comparing the output of the current address detecting means and the output of the address designating means to detect a difference in the number of tracks, and an access operation by the track number difference detecting means,
An access control device for a disc player, comprising: a correction unit for detecting the difference in the number of tracks again and correcting the amount of movement to the target address at the time of access from the next time by the detection output.