JPH0522986B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION 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, disk-related industries such as video disks and compact disks have been making inroads into the market. All such devices have a means (hereinafter referred to as a disk motor) for rotationally driving the disk.

Such a disk motor performs frequency and phase comparison between the disk motor reference signal and a signal obtained from a frequency generator (FG) attached to the disk motor, thereby controlling the rotation of the disk and simultaneously controlling the disk 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 the disk instead of the FG signal to control the rotation of the disk. This means that when using the FG signal,
This is because even if the FG signal and the reference signal are phase-synchronized, the synchronization signal reproduced from the disk is not necessarily phase-synchronized with the reference signal due to disc slippage or eccentricity.

Furthermore, it is very important that this reference signal and the synchronization signal to be reproduced are phase-synchronized; if they are not phase-synchronized, the reproduced video signal will be disturbed. Therefore, by detecting a phase synchronization signal (hereinafter referred to as a phase lock signal) indicating whether phase synchronization is achieved, the video signal reproduced on the monitor is turned on or off.

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 6 are transmitted to the speed/phase comparator 2.
After passing through the phase compensation circuit 3 and the drive amplifier 4, it is applied to the disk motor 5. 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 (S _I ). That is, only when eight consecutive reference signal pulses are all in phase synchronization with the regenerated synchronization signal pulse, the output of the eight stages becomes High level, and the phase lock signal 11 is output through the NAND gate 9 and the inverter 10. It is now available at High level.

However, since the synchronization signal pulses to be reproduced are signals recorded on the disk, if the disk is scratched, the synchronization signal pulses may not be output even if there is a small scratch that does not cause any problem on the monitor screen. For this reason, there is a possibility that the video signal output to the monitor may be determined to be out of phase synchronization with the disk motor, and may be turned off more often than necessary. Therefore, the conventional phase synchronization detection method using the synchronization signal reproduced from the disk has the above-mentioned problems and cannot drive the disk stably.

Purpose of the invention The purpose of the present invention is to
The purpose is to drive the disk stably using reproduction synchronization signal pulses.

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

DESCRIPTION OF THE EMBODIMENT 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 reference signal pulse is used as a clock input in the shift register 8, and the reproduction synchronization signal pulse 7 is used as a serial input, and the output is sent to the majority circuit 1.
2, and its output is obtained as the phase lock signal 11. With such a configuration, a phase lock signal can be obtained based on a predetermined majority ratio. FIG. 4 shows an example of a majority circuit (Patent Publication No. 134751/1982).

In the same figure, 12a is a resistor with the same value.
_R1 to _R8 , 12b are comparison voltages, and 12c is a comparator. By appropriately selecting the comparison voltage _ER , the majority ratio can be determined. In other words, if the output voltage of shift registers Q _A to Q _H is V _S , set E _R to a value determined by n/8 V _S > E _R > n-1/8 V _S (where n is an integer from 1 to 9). This can be achieved by doing this. In the case of an 8-stage shift register as in this embodiment, for example, V _S
If you set = 10V, E _R ≒ 5.5V, the majority ratio will be 5:3.
Therefore, even if three out of eight reproduction synchronizing signal pulses are missing due to scratches or the like during disc reproduction, the phase lock signal 11 does not change.

FIG. 3 is a block diagram of another embodiment of the invention, in which the same reference numerals as in FIG. 2 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 in operation. In Fig. 4, this corresponds to switching _ER . That is,
It is important to ensure that the disk motor reaches the specified rotation speed at startup, so the majority ratio is set to a large value such as 7:1 or 6:2, and once the disk motor reaches the specified rotation speed, In order to drive stably without being affected by scratches on the disk, the majority vote ratio is set to be small, such as 4:4 or 5:3. In this way, by switching the majority vote 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 depending on how many consecutive N reference signal pulses and reproduction synchronization signal pulses are in phase synchronization relationship. It is possible to judge whether or not the disk is rotating at a predetermined number of rotations, and the criterion for this judgment can be arbitrarily set by changing the majority voting ratio, and the disk motor can be driven more stably according to the state of the disk. Furthermore, by using a microcomputer or the like, more diverse majority circuits can be easily realized, and stable phase lock signals can be detected. 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 an embodiment of the present invention, and FIG. 4 is a block diagram of essential parts of the same embodiment. 1...Reference signal pulse generation circuit, 2...Speed/
Phase comparator, 3... Phase compensation circuit, 4... Disc motor drive amplifier, 5... Disc motor, 6
...Disk, 8...8-stage shift register, 1
2...Majority circuit.

Claims (1)

[Scope of Claims] 1. Used when rotating a disc-shaped recording medium on which information signals such as video signals are recorded, and having a pulse generation circuit that generates reference signal pulses, and having a pulse generation circuit that generates a continuous number of N reference signal pulses. The apparatus is configured to detect whether or not the disc-shaped recording medium has reached a predetermined rotation speed based on the number of pulses that are in phase synchronization with a synchronization signal pulse reproduced from the disc-shaped recording medium. A rotary drive device. 2. Claim 1, wherein the standard for the number of pulses in a phase-synchronized relationship for determining whether the disc-shaped recording medium has reached a predetermined rotation speed is changed between startup and operation. The rotary drive device described.