JPH0298880A - Control method for servo system of disk player - Google Patents

Abstract

PURPOSE:To eliminate need for reset transmission characteristics for the same disk by setting the transmission characteristics of the servo system corresponding to a selected disk, storing them corresponding to storage position information on the disk, and holding the characteristics until the characteristics are reset. CONSTITUTION:For the servo system which processes digitally an error signal generated based on the output signal of a pickup 6 for reading recording information out of the disk D1, the transmission characteristics of the servo system are set according to the selected disk D1. Then the set value is stored corresponding to information on storage positions D1-D6 on the disk and held until the corresponding storage holding states of the disk are released. Consequently, the resetting of the transmission characteristics of the servo system for the same disk is omitted and the play of next specified music is started speedily.

Description

TECHNICAL FIELD The present invention relates to a method of controlling a servo system, and more particularly to a method of controlling a servo system in a disc player that simultaneously stores and holds a plurality of discs and selectively plays them.

BACKGROUND ART Disc players that play information recording discs such as video discs and digital audio discs are equipped with a tracking servo system for controlling the pickup spot to always accurately follow the recording track regardless of the eccentricity of the disc, etc. A focus servo system is essential for controlling the pickup spot so that it can be properly focused on the information recording surface of the disk regardless of disk warpage or the like.

Recently, digital servos have been used as these servo systems, which perform A/D (analog/digital) conversion and digital processing of error signals generated based on the output signal of a pickup that reads recorded information from a disk. There is. According to this digital servo, the error signal p
Since the -p value (difference between positive and negative peak values) etc. differs from disk to disk, the transfer characteristics such as the loop gain of the servo system can be freely set for each disk accordingly. In the past, the transfer characteristics of the servo system were set by playing a specific location on a specific disc during manufacture, but in systems using digital servos, the transfer characteristics of the servo system were set for each disc by playing the performance. It was done on occasion.

By the way, for example, by storing and setting a plurality of discs in a magazine, you can play a continuous performance in which a plurality of discs are played in succession, a program performance in which music is played in a pre-designated order, or a random number according to a random number. There are so-called multi-disc players that are capable of random performance by selecting and playing songs. In this multi-disc player, during programmed play or random play, the disc that has been played once is selected and played again, and the player employs a digital servo, so that it is possible to select and play the disc that has been played once again. If you try to set the transmission characteristics of the servo system during that performance, the settings will be reset every time you select even the same disc, and the time required for resetting will be used for the next specified song. will be delayed.

SUMMARY OF THE INVENTION Therefore, the present invention provides a control system for a servo system in a disc player that eliminates the need to reset the transmission characteristics of the servo system for the same disc, and allows a quick transition to playing the next designated piece of music. The purpose is to provide a method.

The servo system control method according to the present invention is a disc player that stores and holds multiple discs at the same time and plays them selectively. 1. For servo systems that digitally process signals. Then, set the transmission characteristics of the servo system according to the selected disk, and store this setting value in correspondence with the storage position information of the disk,
This storage setting value is held until the corresponding disk is released from the storage/holding state.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a schematic diagram showing, for example, a multi-disc player to which the servo system control method according to the present invention is applied. In the figure, a magazine 1 that stores, for example, six disks in sequence at a predetermined pitch, is provided with six trays (not shown) that carry disks so as to be able to protrude from and be housed in the magazine body. The magazine 1 is detachably mounted 6 on a predetermined neck portion of the player body. The magazine mounting section is provided with a removal detection switch 2 that detects that the magazine 1 has been removed from the neck mounting section, and this detection output is supplied to a system controller 18, which will be described later. One of the six disks D1 to D6 stored on each of the six trays provided in the magazine 1 is taken out by the disk ejecting and conveying mechanism 3, and is further fixed to the rotating shaft of the spindle motor 4. It is conveyed onto the turntable 5 and clamped.

The disc ejecting and transporting mechanism 3 includes a protruding member that protrudes the tray of the magazine 1 and moves the disc onto the turntable 5, and a clamp mechanism that clamps the disc when the disc is moved onto the turntable 5 by the protruding member. A movable plate that changes the relative position of the protruding member with respect to the magazine 1 in the arrangement direction of the storage disks, and a sensor that detects the position of this movable plate, the operation of the clamp mechanism, etc. are used. In this disk ejecting and conveying mechanism 3, the movable plate is driven by a motor Ma, and the protruding member is driven by a motor Mb. By moving the movable plate, the position of the protruding member is changed, and a disc can be selected. It has become. The configurations of the magazine 1 and the disk ejecting and transporting mechanism 3 are described in detail in, for example, Japanese Patent Laid-Open No. 14369/1983.

Recorded information on a disk rotationally driven by a spindle motor 4 is read by an optical pickup 6.

The pickup 6 includes a laser diode as a light source, an optical system including an objective lens, a photodetector that receives reflected light from the disk, and a focus that controls the position of the objective lens in the optical axis direction with respect to the information recording surface of the disk. An actuator and a tracking actuator for controlling the position of the beam spot emitted from the pickup 6 in the recording track in the disk radial direction are built in. The pickup 6 is mounted on a carriage (not shown) that is movable in the radial direction of the disk.

The tracking error generation circuit 7 generates a tracking error by a well-known generation method such as the three-beam method.
The focus error generation circuit 8 generates a focus error signal using a well-known generation method such as the astigmatism method.

Tracking error signal and focus error signal are V
It is supplied to MPX (multiplexer) 11 via CA (1!pressure control width unit) 9 and 10. MPXII sends the tracking error signal and focus error signal to the next stage A.
/D converter 12 in a time-division manner. Each error signal digitized by the A/D converter 12 is compensated for its frequency characteristics by a digital equalizer (EQ) 13, and then supplied to a PWM (pulse width modulation) circuit 141 to adjust the magnitude (level) of the error signal. A drive signal with a corresponding pulse width is supplied to the tracking actuator and focus actuator described above. In addition, the PWM circuit 14 also generates a drive signal with a pulse width corresponding to the signal level after the digital EQ 13 extracts the low-frequency component of the tracking error signal and compensates for the frequency characteristics. is supplied to the drive motor of the carriage. As described above, a servo system is constructed which A/D converts each error signal and processes it digitally, and this servo system is controlled by a servo controller 15 consisting of a microcomputer. This servo controller 15 controls on (close) and off (open) of each servo loop.
It controls the gain of the VCAs 9 and 10, the equalizer characteristics of the digital EQ 13, etc.

The read RF multiplied signal of the pickup 5 is supplied to the RF reproduction circuit 16. If the disc to be played is a compact disc, for example, the read RF multiplied signal EF M (Eight
This EFM signal is EFM demodulated and error corrected in the RF reproduction circuit 16, and then D/A (digital/analog) converted to become left and right audio outputs. Further, in the RF reproducing circuit 16, a phase error signal is generated according to the phase difference between the reproduced clock extracted from the read RF multiplied signal and the reference clock, and the EF
Subcode information is decoded from the M demodulated data. The phase error signal is converted to PWM via the servo controller 15.
The signal is supplied to the circuit 17 and then supplied to the spindle motor 4 as a drive signal with a pulse width corresponding to the error signal level.

The subcode information is provided to system controller 18.

The system controller 18 is constituted by a microcomputer, and controls the entire system including the servo controller 15 in response to key operation commands from the keyboard 19, controls the display 20, and changes discs during continuous play, program play, or random play. In addition to controlling the drive of the motors Ma and Mb according to the music selection and music selection, it also sets the transmission characteristics of the servo system for each disc when playing the specified disc, and uses this setting value to adjust the storage position of the disc (magazine 1). In addition, control is performed to clear the stored set value in response to the detection output of the above-mentioned removal detection switch 2.

Next, the processing procedure l:' of the servo system control method according to the present invention executed by the processor of the system controller 18 will be explained according to the flowchart j. of FIG.

For example, in a program performance, when UNYZA is playing magazine 1,
Select the disc and song in the list and press the key 1 on the keyboard 19. When a start command is issued after this, Bromo Tsusa first selects the designated disc from the magazine 1 by controlling the drive fi of the disc ejecting and transporting mechanism 3 and loads it onto the turntable 4 (step S1).
When the loading completion is detected in response to the detection output of the loading completion detection switch (not shown) (step S2), the spindle motor 4 is started (step S3), and then the loaded disk is re-designated. (Step S4)
). If it is the first specification, execute the process of transfer characteristic setting mode in which the transfer characteristics of each servo system for tracking and focusing are set according to the magnitude of each error signal obtained in the open state of each servo loop (step S5). , then change the setting value to the disk storage position (magazine 1 tray)
RA Fv with the corresponding disk number and correspondence relationship.
At the same time, the transfer characteristics of each servo system are controlled to be the characteristics set in the transfer characteristic setting mode (step S7). Note that the processing procedure of the characteristic setting mode in step S5 will be described later. If it is determined in step S4 that the disk has been re-designated, read out the storage setting values already stored in the RAM in correspondence with the disk number (step S3);
After L is completed, the process moves to step S7.

Next, the lead-in area ζ; self-recorded TOC
(Table Or Contents) Execute information reading mode processing (step S9), determine whether there is a song specification after L (step 510), and if there is a song specification, execute search mode processing for the specified song Step 5ll), then move to Blame Mode (Step 51).
2). If no music is specified, the process directly proceeds to step S12. When the end of the specified song is detected (step 31)
3) Determine whether or not the next designated song is on the same disc. Step S1.4) If the designated song is on the same disc, return to step Sll and execute the search process for the designated song. . If the song is not specified on the same disc, the drive of the spindle motor 4 is stopped in step 51.
5) After that, the disk is returned to its original position in the magazine 1 by driving and controlling the disk ejecting and transporting mechanism 3 (step 516). Next, it is determined whether or not another disk is designated (step 517). If there is a designation, the process returns to step S1 and the series of processes described above are executed. If no other disk is specified, it is determined whether the magazine 1 has been removed by monitoring the output of the removal detection switch 2 (step S] 3). If removal of the magazine 1 is detected, the RA is activated in step S6. The stored setting value stored in M is cleared (step 519).

In this way, the transmission characteristics of the servo system are set according to the magnitude of the error signal generated when the servo loop is open when the selected disc is played, and this set value is stored in correspondence with the disc number. The stored setting values are retained until magazine 1 is removed, and when the newly specified disk is loaded, the corresponding stored settings are read out and the transmission characteristics of the servo system are controlled. Since the process of resetting the transfer characteristics of the music is not necessary, the time required for resetting can be omitted, and the performance of the next designated piece of music can be quickly performed.

Next, the processing procedure of the transfer characteristic setting mode mentioned above will be explained according to the flowchart of FIG. 3. In addition,
In this transfer characteristic setting mode, among the transfer characteristics of each servo system for tracking and focusing, for example, six gain constants and GF, which determine six lube gains, are set. Further, this subroutine is executed in a predetermined cycle.

First, the processor drives the focus actuator in order to gradually bring the objective lens closer to the disk from its initial position, which is sufficiently far away from the disk, while the tracking and focusing servo loops are open (step 521).
). Due to this drive, the focus error signal exhibits a so-called figure-eight curve characteristic as shown in FIG. 4 with respect to the distance of the objective lens from the disk, and the zero cross point becomes the focal position of the objective lens. This focus error data is captured (step 522), the pp value (positive and negative peak values of the error signal) is calculated based on this captured data, and the loop gain of the focus servo loop is determined from this pp value. A constant GF is set (step 523). Regarding the processing procedure for calculating this p-p value and setting the gain constant GF, please refer to Japanese Patent Application Laid-Open No. 63-106003.
It is described in detail in the publication.

On the other hand, when the servo loop is open, the pickup spot cannot follow the recording track and the disk is eccentric, so the tracking error signal changes as the disk rotates as shown in Figure 5. Error data is fetched (step 524), a pp value is calculated based on the fetched data, and a gain constant GT for determining the loop gain of the tracking servo loop is set from this pp value (step 525). This p-
The processing procedure for calculating the p value and setting the gain constant GT is also described in detail in the previous publication.

The information on the gain constants GT and GF set in this way is
It is applied to the servo controller 15 in step S7 in the flowchart of the figure, and the servo controller 15 controls the gains of the VCAs 9 and 1.0 so that the loop gains correspond to the gain constants GT and CF. This results in
This means that the optimum servo system transmission characteristics can be set for each disk.

In the above embodiment, a case has been described in which the application is applied to a magazine disc player that plays a plurality of discs stored in a single magazine 1, but the invention is not limited to this. It can also be applied to magazine disc players that can hold discs, tray-type disc players that have two or more disc loading trays, and disc players that play by placing two or more discs on a roulette-like turntable. In short, the present invention is applicable to all disc players that store and hold a plurality of discs at the same time and selectively play them. In this case, in a magazine/disk player that can hold multiple magazines, when the removal of one magazine (M removal) is detected, the memory settings for the disk corresponding to that magazine are cleared, and the tray In a type disc player, when one tray performs an eject operation, the stored setting value for the disc number corresponding to that tray may be cleared.

Furthermore, in a disc player that plays by arranging two or more discs in a roulette pattern, the stored setting value may be cleared by detecting the protrusion of the turntable.

Furthermore, in the above embodiment, as a method of setting the servo characteristics, a method of setting according to the magnitude of the error signal obtained in the open state of the servo loop was described, but the magnitude of the error signal obtained in the closed state of the servo loop is The same effect can be obtained by setting the servo characteristics according to the performance and storing the data for each disk.

As described in detail, according to the servo system control method of the present invention, in a disc player that stores and holds a plurality of discs at the same time and selectively plays them, the control method according to the selected disc Sets the transmission characteristics of the servo system and stores this setting value in correspondence with the storage position information of the disk,
By retaining this memory setting value until the corresponding disk is released from the storage/holding state, when the same disk is loaded, the corresponding memory setting value can be read out and the transmission characteristics of the servo system can be controlled. This eliminates the need for resetting the transfer characteristics of the disc, and allows a quick transition to the performance of the next designated piece of music.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a multi-disk player to which the servo system control method according to the present invention is applied, FIG. 2 is a flowchart showing the processing procedure of the servo system control method according to the present invention, and FIG. 3 is a transmission diagram. Figure 4 is a waveform diagram showing the waveform change of the focus error signal depending on the distance of the objective lens from the disk surface. FIG. 3 is a waveform diagram showing waveform changes of the track/error signal in the open state. Explanation of symbols of main parts 1... Magazine 2... Extraction detection switch 6... Pick up 7... Tracking error generation circuit 8...
... Focus error generation circuit 9.10 ... Voltage control amplifier 11 ... Multiplexer 14.17 ... Pulse width modulation circuit 15 ...
...Servo controller 16...RF regeneration circuit

Claims (3)

[Claims] (1) In a disc player that stores and holds multiple discs simultaneously and plays them selectively, a servo system that digitally processes an error signal generated based on the output signal of a pickup that reads recorded information from the disc. A control method that sets a transmission characteristic of a servo system according to a selected disk, stores this setting value in correspondence with storage position information of the disk, and uses this stored setting value to control the storage/holding state of the corresponding disk. A servo system control method characterized by holding the servo system until release of the servo system is detected. (2) The disc player is a magazine disc player, and the detection of release of the storage and holding state of the disc is as follows:
2. The method of controlling a servo system according to claim 1, wherein the control method is performed by detecting removal of the first magazine. (3) The servo according to claim 1, wherein the disc player has two or more disc loading trays, and the release of the storage/holding state of the disc is detected by detecting protrusion of the tray. How to control the system.