JPH0569348B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a video disc player that plays back video signals from an optical disc on which video signals are recorded at a constant linear velocity, and particularly relates to a video disc player that plays back video signals from an optical disc on which the video signals are recorded at a constant linear velocity, and particularly relates to a video disc player that plays back video signals from an optical disc on which video signals are recorded at a constant linear velocity. This invention relates to a device for performing special playback.

(Prior Art) There are generally two types of video disc players: VHD format and LV format. In LV format video disc players, laser light is directed from the inner circumference to the outer circumference of the disc The recorded signal is reproduced by traying it in a spiral manner. Further, LV type optical discs include CAV discs in which video signals are recorded at a constant angular velocity in two fields per track revolution, and CLV discs in which video signals are recorded at a constant linear velocity.

A CLV videotask player is equipped with a disk rotation control circuit 23 as shown in Fig. 4 in order to keep the linear velocity constant during signal reproduction, and is equipped with a disk rotation control circuit 23 as shown in Fig. The rotational speed of the spindle motor 22 that drives the optical disk is controlled so that the phases match. That is, the reproduced signal from the pickup 2 is connected to the horizontal synchronization separation circuit 19 to extract a horizontal synchronization signal, and the phase of the horizontal synchronization signal and the reference signal from the reference signal generation circuit 20 is compared in the comparison circuit 21. , a phase error signal created based on this is sent to the spindle motor 22 to perform speed servo of the motor.

In CLV disks, the synchronization signals are formed at equal intervals on the tracks and are not lined up in a line in the disk radial direction, so during special playback, the playback synchronization signals become discontinuous before and after the track jump, causing the playback screen to change. Color distortion, vertical synchronization disturbance, horizontal skew, etc. occur.

Therefore, a video disc player has been proposed that can play back normal images by writing one field of video signal to a video memory and then reading the signal from the memory at an appropriate timing during special playback of a CLV disc ( Japanese Unexamined Patent Publication 1983-
139577 (HO4N5/93).

(Problem to be Solved) In video disc players, special playback consists of a jump operation in which the pickup jumps between tracks in the radial direction of the disc, and signal playback at normal speed (hereinafter referred to as normal playback). This is done through repetition, but traditionally,
The pick-up jump width and jump period are
It is set to a constant value for each special playback mode.
However, when performing normal playback after a jump operation, the time it takes for the disk rotation control circuit 23 to operate and the rotation of the optical disk to be set to a predetermined value (hereinafter referred to as recovery time) is longer than the time required for the optical disk to rotate. It is greatly influenced by the amount of eccentricity, etc. Therefore, if the recovery time is longer than the jump period, a track jump is performed and writing to the memory is performed before reproduction at an appropriate speed, resulting in disturbances in the special reproduction screen.

(Means for Solving the Problems) The present invention has been made to solve the above problems.

The video disc player according to the present invention includes a pickup 2 for signal reproduction, a memory 10 in which one field or one frame of the reproduced video signal is written as a still image signal, and a horizontal synchronization signal in the reproduced video signal. A disk rotation control circuit 23 that controls the rotation speed of the optical disk 1 so that the phase matches the reference signal, a jump drive section 6 that jumps the pickup 2 during special playback, and a jump amount connected to the drive section. It is provided with a control circuit 7 and a switching means for appropriately switching and outputting the reproduced video signal from the pickup 2 and the still image signal read from the memory 10 during special reproduction.

Further, the jump amount control circuit 7
The operation of the jump drive unit 6 is controlled by changing the period T and pulse width B of the jump pulse P to be sent to the jump drive unit 6, for example, depending on the magnitude of the disturbance in the disk rotation control that occurs during the jump. As a result, the pickup 2 performs a jump operation with a period and width depending on the magnitude of the disturbance.

(Functions and Effects) In special playback, when normal playback is performed after jump operation, the jump amount control circuit 7
If the disk rotation control is greatly disturbed and the recovery time is long, the pulse width B of the jump pulse is increased and the pulse period T is set longer, thereby generating a jump pulse P that will result in the desired special playback screen. .

The jump pulse P is supplied to the jump drive unit 6, whereby the pickup 2 performs a jump operation with a jump amount according to the pulse width B and a jump period according to the pulse period T.

Therefore, even if the recovery time is long, normal playback is performed after the disk reaches its normal rotational speed, so a stable special playback screen without any disturbances can be obtained.

(Embodiment) FIG. 1 shows a circuit configuration of a video disc player according to the present invention.

A pickup 2 for reproducing a video signal from an optical disk 1 is conveyed in the radial direction of the disk by a pickup conveyance means (not shown) whose operation is controlled by a pickup drive circuit 3, and traces the signal surface.

Further, the jump drive section 6 that jumps the pick-up 2 during special playback is equipped with a magnet disposed in a movable section consisting of a semiconductor laser, an objective lens, etc., and a trunking coil that drives the magnet in the tracking direction, as is well known. It is composed of an electromagnetic drive device. A jump amount control circuit 7 is connected to the jump drive section 6, which generates a jump pulse having a predetermined pulse width and cycle during special reproduction.

The main control circuit 4 is composed of a microcomputer, and controls the overall operation of the video disc player, and various playback modes are set by operating a key input device 5 connected to the main control circuit 4.

The reproduced signal a from the pickup 2 is transmitted to the demodulation circuit 8.
After being demodulated, one field's worth of video signals is written into a memory 10 whose write timing is controlled by an input timing generation circuit 9.

At this time, the write permission determination unit 13 determines that the reproduction signal a
Determine whether there is any disturbance in the synchronization signal, burst signal, etc. inside, and if these signals are normal,
A write permission signal is sent to the input timing generation circuit 9. Therefore, when a disturbance occurs in the burst signal or the like, writing to the memory 10 is not performed.

The output signal b of the demodulation circuit 8 and the output signal c of the memory 10 are connected to both input terminals of a changeover switch 14 controlled by an output timing generation circuit 12, respectively. Further, the output signal b of the demodulation circuit 8 is connected to the phase comparison circuit 11. As mentioned above, when the jump operation and normal playback are repeated during special playback, the phase comparator circuit 11 outputs both the output signals b and c.
When the phases of both output signals match, a match signal e is sent to the output timing generation circuit 12.

The output timing generation circuit 12 switches the changeover switch 14 based on the input of the coincidence signal e, and outputs the output signal c of the memory 10 during the jump operation.
is selected, and the output signal b of the demodulation circuit 8 is selected and output at an appropriate time after the jump is completed. The output signal d is supplied to the monitor device, and as a result, a stable special reproduction image without any disturbance is displayed on the screen.

FIG. 2 shows an example of the configuration of the jump amount control circuit 7 that should operate during special playback. The time detection section 15 for detecting the recovery time of disk rotation control is constituted by a flip-flop circuit as shown. Each input terminal of the flip-flop circuit has a vertical synchronizing signal VS, which is "H" when the time base collector installed in the video signal reproduction system is operating normally and is in lock mode, and "L" when it is not locked.
The TBC lock signal, the M lock signal which changes from "L" to "H" when the rotational speed of the spindle motor becomes constant, and the signal J which becomes "L" when a jump pulse occurs, operate the logic gate shown in the figure. connected via. As a result, both the lock signals become "H" after the jump pulse is generated.
The vertical synchronization signals VS generated until VS is counted. The comparison calculation unit 17 is the time detection unit 15
The count value of is converted into a recovery time X, and the recovery time X is compared with a reference time Y sent from the set time generation section 16, and pulse width information is provided to the jump pulse generation section 18 based on the comparison result.
Create CB and cycle information CT. Based on both information, if _the recovery _time If the recovery time X is shorter than the reference time Y, a jump pulse with a small pulse width B ₂ and period T ₂ is generated as shown in FIG. 3b.
Note that when the pulse width and period of the jump pulse are changed in this manner, the pulse width (and thus the jump width) is set so that special reproduction at the same speed is performed as a result.

The jump pulse P is sent to the jump driving section 6 shown in FIG. 1, and the jump width and jump period of the pickup 2 are determined. As a result, when the speed servo response by the disk rotation control circuit 23 is fast, the jump operation is performed in small steps.
When the response is slow, the jump operation is performed in a relatively long cycle.

Therefore, even if the recovery time of the disk rotation control is long, normal playback is performed after the disk reaches the normal rotational speed, so a stable special playback screen without disturbance can be obtained.

Note that the configuration of each part of the present invention is not limited to the above embodiments,
Of course, various modifications are possible within the technical scope of the claims.

For example, the jump amount control circuit 7 shown in FIGS. 1 and 2 can be configured together with the main control circuit 4 by a microcomputer.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a video disc player according to the present invention, FIG. 2 is a block diagram of a jump amount control circuit, and FIG. 3 is a timing chart of two types of jump pulses with different pulse widths and periods. FIG. 4 is a block diagram of the disk rotation control circuit. 1... Optical disk, 2... Pickup, 7... Jump amount control circuit, 23... Disk rotation control circuit.

Claims (1)

[Claims] 1. In a video disk player that plays back video signals from an optical disk 1 on which video signals are recorded at a constant linear velocity, a pickup 2 for signal playback;
One reproduced field area is stored in the memory 10 where one frame of video signal is written as a still image signal.
, a disk rotation control circuit 23 that controls the rotational speed of the optical disk 1 so that the horizontal synchronization signal in the reproduced video signal and the reference signal match in phase, and a jump drive section that jumps the pickup 2 during special playback. 6, a jump amount control circuit 7 connected to the drive section, and a pick-up 2 during special playback.
The jump amount control circuit 7 includes switching means for appropriately switching and outputting the reproduced video signal from the pickup 2 and the still image signal read from the memory 10. A video disk player characterized in that a jump driving section 6 is controlled according to the magnitude of the disturbance, and the pickup 2 performs a jump operation with a period and width corresponding to the magnitude of the disturbance.