JPS60223069A - Revolution controller - Google Patents

Abstract

PURPOSE:To use a reproduction synchronizing signal pulse regardless of the injury of a disk and to attain the stable drive of the disk, by providing a majority decision circuit to a rotary driver. CONSTITUTION:A shift register 8 uses as a reference signal pulse into a clock input and a reproduction synchronizing signal pulse 7 as a series input respectively. The output of the register 8 is supplied to a majority decision circuit 12 and used as a phase clock signal 11. In such a way, a phase lock signal is obtained according to a ratio of majority decision which is set previously. For instance, said ratio is set at 5:3 with an 8-step shift register. Therefore, no problem is produced even if three reproduction synchronizing pulses are lost at most owing to the injury of a disk 6 in a reproduction mode. Furthermore the ratio of majority decision is changed by a switching signal 13 for said ratio. In other words, said ratio is increased up to 7:1, for example, in a starting time point. Then the disk 6 is driven stably after the number of revolutions of a disk motor reaches a prescribed level.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotational drive device used for rotationally driving a disk-shaped recording medium (hereinafter referred to as a disk) such as a video disk.

Conventional configurations and their problems In recent years, disc-related industries such as video discs and compact discs have been making inroads into the market. All such devices have a means (hereinafter referred to as a disk motor) for rotating the disk.

Such a disc motor performs frequency and phase comparison between the disc motor reference signal and a signal obtained from a frequency generator (FG) attached to the disc motor, thereby controlling the disc rotation and simultaneously controlling the disc rotation. It also detects whether the phase is synchronized with the reference signal.

There is also a method of using a synchronization signal reproduced from a disk instead of the FG double signal. This is because when using the FG signal, even if the phase of the FG double signal reference signal is synchronized, the synchronization signal reproduced from the disc may not always be in phase synchronization with the reference signal due to disc slippage or eccentricity. This is because it does not necessarily mean that

Furthermore, it is very important that this reference signal and the synchronization signal to be reproduced are phase-synchronized. ON1 of
0 FF etc.

FIG. 1 shows an example of a block diagram of a conventional optical video disk rotation drive device. The output of the reference signal pulse generation circuit 1 and the synchronization signal pulse 7 reproduced from the disk etc. pass through a speed/phase comparator 2 and then a phase compensation circuit 3.
, and is connected to the disk motor 5 through the drive amplifier 4. There is also an eight-stage shift register 8, in which the reproduction synchronizing signal pulse 7 is used as a clock input (CK), and the reference signal pulse is used as a serial input (8i). That is, consecutive 8
The output of the 8th stage is High only when the reference signal pulse is in phase synchronization with the regenerated synchronization signal.
H level craftsman, NAND gate 9. A phase lock signal 11 is obtained at utgh level via an inverter 1o.

However, since the synchronization signal pulse to be reproduced is a signal recorded on the disc, if there is a scratch on the disc, the synchronization signal pulse may not be output even if there is a small scratch that is not noticeable on the monitor screen. For this reason, there is a possibility that the video signal going to the monitor is considered to be out of phase synchronization with the disk motor, and is turned off even though it is not necessary. Therefore, conventional phase synchronization detection methods have problems when handling such disks, and cannot drive the disk stably.

OBJECTS OF THE INVENTION An object of the present invention is to stably drive a disk using reproduction synchronization signal pulses, regardless of scratches or the like on the disk.

Structure of the Invention In order to achieve the above object, the rotary drive device of the present invention has N
This circuit is equipped with a circuit that compares N consecutive reference signal pulses and reproduction synchronization signal pulses and detects how many of the N pulses are in phase synchronization with the reproduction synchronization signal, that is, a majority circuit. Even if the reproduction synchronizing signal pulse is missing due to scratches or the like during disk reproduction, the phase lock signal will not be reversed and the disk can be driven stably.

DESCRIPTION OF THE EMBODIMENTS FIG. 2 is a block diagram showing an embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate the same elements. The feature of this embodiment is that the shift register 8 uses the reference signal pulse as a clock input, the reproduction synchronization signal pulse 7 as a serial input, and its output goes into the majority voting circuit 12, and the output is obtained as the phase lock signal 11. be. With such a configuration, a phase lock signal can be obtained based on a predetermined majority ratio. Further, in the case of an 8-stage shift register as in this embodiment, if the ratio is 6:3, for example, there will be no problem even if up to three reproduction synchronizing signal pulses are missing due to disc reproduction damage.

FIG. 3 is a block diagram of another embodiment of the present invention;
The same reference numerals as in the figure indicate the same elements. The feature of this embodiment is that the majority ratio is switched by the majority ratio switching signal 13 when the disk motor is started and when it is running. In other words, it is important to ensure that the disc motor reaches a predetermined rotation speed at startup, so the majority voting ratio is set to a large value such as 7:1 or 6:2.
Once the disk motor reaches a predetermined rotational speed, the majority ratio is set to be small, such as 4:4 or 6:3, in order to drive the disk stably without being affected by scratches or the like on the disk. In this way, by switching the majority ratio between when the disk motor is started and when it is running, more stable driving can be achieved.

Effects of the Invention As described above, according to the present invention, by employing a majority circuit, the disc motor is controlled to perform a predetermined operation depending on how many consecutive N reference signal pulses and reproduction synchronization signal pulses are in a phase synchronization relationship. It is possible to judge whether or not the disk is rotating based on the number of rotations, and the criterion for this judgment can be arbitrarily set by changing the majority voting ratio, making it possible to drive the disk motor more stably depending on the state of the disk. As described above, the present invention is a very effective means for controlling the rotation of a disk motor using reproduction synchronizing signal pulses from the disk.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional rotary drive device,
FIGS. 2 and 3 are block diagrams of one embodiment of the present invention. 1...Reference signal pulse generation circuit, 2...Speed-
Phase comparator, 3... Phase compensation circuit, 4...-...
Disk motor drive a/g, 6--disc motor, 6-disc, 8-8-stage shift register, 12-majority circuit. Name of agent: Patent attorney Toshio Nakao and 1 other Tadayoshi
1 figure

Claims (2)

[Claims] (1) It is used when rotating a disc-shaped recording medium on which information signals such as video signals are recorded, and has a pulse generation circuit that generates reference signal pulses, and among the N consecutive reference signal pulses, Depending on the number of pulses that are in phase synchronization with the synchronization signal pulse reproduced from the disk-shaped recording medium,
A rotary drive device configured to detect whether or not the disc-shaped recording medium is rotating at a predetermined number of revolutions. (2) Claim No. 1, wherein the standard of the number of pulses in a phase synchronization relationship for determining whether the disc-shaped recording medium is at a predetermined rotation speed is changed between startup and operation. The rotary drive device according to item 1.