JPH0453029B2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a video disc player or a CD player.
Regarding information recording disk performance devices such as players,
In particular, the present invention relates to a search method for address data in such a device.

BACKGROUND ART In order to properly perform so-called random access, which is an advantage of information recording disk performance devices, it is necessary to
Address data (frame number, block number, chapter number, etc.) is preferably assigned to each information block such as a frame or data block so that the address value increases or decreases uniformly, and for example, vertical blanking is performed within each information block. It is recorded in an appropriate part such as the period or the first data section. When a desired information block is to be reproduced, address data corresponding to it is first searched for, and the address data is retrieved by moving the radial position of the pick-up with respect to the disk so that the pick-up can read the address data. Explore.

An example of such an address data search method is the method described in Japanese Patent Laid-Open No. 58-62868. In this conventional method, the address data obtained from the pick-up is compared with the target address data, and the speed of movement of the pick-up cartridge in the disk radial direction, that is, the scan speed, is adjusted and a so-called scan operation is performed to bring the pick-up close to the target address. It is.

In the conventional address data search method described above, the scanning speed must be lower than the speed at which the address data can be read sequentially, and if the difference between the current address and the target address is large, the time required for the search becomes long, and quick random access is required. It was difficult to say that this would necessarily be done.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an address data search method that allows quick random access.

In the address data search method according to the present invention, a measured data map is created by sequentially reading address data using a low-speed scan operation and using the elapsed time as a parameter, and then a high-speed scan is performed from the starting point address to the ending point address to obtain the required data in between. A new estimated data map is obtained by modifying the actual data map based on time, and when the difference between the current address and the target address is larger than a predetermined value, high-speed scanning is performed based on the estimated data map to shorten the access time. I'm trying to get it.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an information recording disk performance device that can be used to implement the address data search method according to the present invention. In this device, an information recording disk 1 such as a video disk or CD disk
is rotated by a spindle motor 2 at a desired rotational speed. It is placed on the turntable 3. The spindle motor 2 is rotated by a spindle servo system 4 to a desired number of revolutions in accordance with a recording format such as CAV or CLV. The pickup 5 aligns its detection point with the information recording track on the information recording disk 1 using the spindle servo controller 6, reads information signals such as video format signals or digital data signals from the track, and supplies the information signals to the demodulator 7. do. The pickup 5 generates a tracking error signal in addition to the information signal, as in the three-beam optical system, and supplies this to the tracking controller 6. The tracking controller 6 uses this to track the pickup 5. A tracking servo is created by driving a servo coil (not shown). The tracking controller 6 further responds to jump pulses from the jump pulse generator 8 to jump the detection point within a relatively short distance while leaving the position of the pickup 5 in the disk radial direction unchanged. Note that the jump pulse generator 8 generates the number of jump pulses designated by the jump pulse designation circuit 9.

On the other hand, the pick-up 5 is carried by a carriage (not shown) that can linearly reciprocate along the radial direction of the disk, and the carriage is driven by a carriage motor via a rack and pinion gear assembly (not shown) or the like. This is done by 10 revolutions. The carriage motor 10 rotates at a speed corresponding to the voltage supplied from the carriage motor driver 11. The carriage motor driver 11 receives either a low-speed scan pulse or a high-speed scan pulse supplied from a low-speed scan pulse generator 12 and a high-speed scan pulse generator 13, and generates a carriage motor drive voltage corresponding thereto. Low speed scan pulse generator 12
The high-speed scan pulse generator 13 and the high-speed scan pulse generator 13 each operate in response to operating commands selectively supplied by a controller 14 comprising a microprocessor or the like. The controller 14 provides the required jump distance to the jump pulse number designation circuit, for example, by the number of tracks. The decoder 15 separates and extracts code data such as a frame number and chapter number from the information signal obtained from the demodulator 7, and the synchronization signal separator 16 separates and extracts synchronization signals such as V sync or H sync from the information signal.
4 executes a built-in program based on the obtained code data or synchronization signal and a command signal from the keyboard 17. The built-in programs of the controller 14 include programs for carrying out various operation modes such as normal playback mode, slow playback mode, and stop motion playback mode in this device, and the programs are executed by a predetermined clock. .

Note that the demodulator information signal is supplied to an external device control system such as a video playback system or audio playback computer (not shown).

2 and 3 are flowcharts showing an address data search method according to the present invention executed by the controller 14, the flowchart in FIG. 2 showing a high-speed scan map type subroutine, and FIG. This figure shows a search subroutine that searches for address data using a high-speed scan map.

That is, as shown in the high-speed scan map formation subroutine of FIG. 2, when the controller 14 learns from, for example, a photo sensor that the disk 1 is placed on the turntable 3, it instructs the spindle servo system 4 to perform a spindle servo operation. (Steps S ₁ and S ₂ ). In this way, when the spindle servo system locks in, it is determined based on the code data obtained from the decoder 15 whether or not the placed disc 1 is a new disc for the disc playback apparatus (step S ₃ ). If the disc has already been played and a data map has been created, the spindle servo is released and the operation is stopped (step _S4 ).

If the mounted disk is new to the device, the controller 14 instructs the low-speed scan pulse generator 12 to perform a low-speed scan operation (step _S5 ), and the controller 14 instructs the low-speed scan pulse generator 12 to perform a low-speed scan operation (step S5). The address data Al assigned to each information block such as the frame number is sequentially read (step S ₆ ), and the address data
Obtain Al as a function of its reading timing (e.g. elapsed time from the start of scan) t, and
Al(t) is stored in a memory such as a RAM (not shown) provided in the controller 14 to form an actual measurement data map (step _S7 ). When the reading of the final address data corresponding to the final frame on the innermost or outermost circumference of disk 1 is completed and the formation of the measured data map is confirmed (step _S8 ),
The controller 14 instructs the high-speed scan pulse generator 13 to perform a high-speed scan (step _S9 ). When it is determined that a predetermined time has elapsed since the high-speed scan command (step _S10 ), the high-speed scan is stopped (step _S11 ), the address data at the stop position is fetched (step _S12 ), and the high-speed scan is started at the high-speed scan start position. The high-speed scan speed is calculated by dividing the difference between the address data at the stop position and the address data at the stop position by the high-speed scan execution time.
Vh(R) (R: measurement area from the high speed scan start position to the stop position) is calculated (step _S13 ).
Now, if the low scan speed is Vl(R), the address data Ah(t) by high speed scan can be obtained by the following equation. That is, Ah(t)=Vh(R)・t={Vh(R)/Vl(R)}・Vl(R)・t={Vh(R)/Vl(R)}・Al(t)... (1) Now that the data map of Al(t) is known, (1)
An estimated data map Ah(t) is obtained by the formula (step S ₁₄ ). If the estimated data map formation subroutine is executed each time a disc is reproduced or a scan is started, it is possible to cope with changes in the carriage feed speed due to aging of the apparatus.

FIG. 3 shows an example of the measured and estimated data maps Al(t) and Ah(t) obtained by the above subroutine.

The operation of the controller 14 when performing a high-speed address data search using the estimated data map Ah(t) obtained in this way will be explained with reference to the flowchart of FIG. That is, a search command is sent to the controller 14 by specifying a target address or information block such as a song using the keyboard 17.
(step _S20 ), it is first determined whether an estimated data map has been created for the disk placed at that time (step _S21 ), and if the disk does not have an estimated data map, the estimated data map formation subroutine is executed. Execute (step
_S22 ), the current address of the pick-up 5 is detected (step _S23 ). Next, detect the difference between the current address and the target address (step _S24 ),
It is determined whether the address requires high-speed scanning (step _S25 ), and when it is determined that high-speed scanning is necessary, the required scan time is determined based on the estimated data map that has already been obtained, and high-speed scanning is executed. (Step _S26 ). After executing this high-speed scan, the short-distance jump operation is continued until the current address matches the target address (step _S27 ,
_S28 ).

Effects of the Invention As is clear from the above explanation, according to the address data search method according to the present invention, an estimated data map for high-speed scan is formed from the measured data map obtained by low-speed scan, and the scan data map obtained using this Since the device performs a high-speed scan over time to bring the pick-up close to the target address and then performs a short-distance jump operation to capture the target address data, the address data search can be executed in a short time.

Furthermore, by executing a low-speed scan each time a disk is placed and updating the data map, it is possible to cope with changes in the device over time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an information recording disk performance device capable of implementing the address data search method according to the present invention, FIGS. 2 and 4 are flowcharts showing the address data search method according to the present invention, and FIG. 3 is a graph showing an example of a data map obtained by the subroutine operations shown in the flowchart of FIG. 2; Explanation of symbols of main parts: 1...information recording disk, 2...spindle motor, 3...turntable, 5...pickup, 10...carriage motor.

Claims (1)

[Scope of Claims] 1. An information reading method in a pick-up disk performance device that can select a pick-up jumping speed (scan speed) under a spindle servo lock-in state of a disk rotating body, which blocks recorded information by low-speed scanning. A data map is formed by sequentially reading the address data assigned to each time using the elapsed time from the start of the low-speed scan as a parameter, and then executing the high-speed scan for a predetermined time to calculate the amount of change in the read address data between the start and end of the high-speed scan. correcting the data map based on the predetermined time and the amount of change to form an estimated data map, and performing a high-speed scan based on the estimated data map to bring the pick-up closer to the recording location of the target address data. An address data search method characterized by: