JPH0329776Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a disk player having a pause function.

Conventionally, when playing back images recorded on a disk with a constant linear velocity (CLV disk) in a video disk player, etc., it is impossible to keep the image still (so-called stop motion), so it is impossible to keep the image still (so-called stop motion). To temporarily stop playback, perform a pause operation, open the servo circuit of the slider that slides the position in the disk radial direction relative to the disk and signal readout device, and leave the tracking servo circuit closed. A stopper is electrically activated at the rotation limit of a tracking device such as a tracking mirror, and the tracking device is operated only within a predetermined range.

However, when a pause operation is performed during playback of an image recorded on the outer periphery of the disk, where the angular velocity is particularly low, the time it takes for the tracking mirror to reach its rotation limit is longer than when the tracking mirror is centered within the disk. When the pause is canceled, playback starts from a point where a considerable amount of time has passed from the position of the image that was played immediately before the pause was released, and there is a considerable number of gaps between the image immediately before the pause starts and the image that is played when the pause is canceled. There are images for 1 frame, and the images during this period are not reproduced, and in order to view the images during this period, it is necessary to go to the trouble of returning to the reproduction position and restarting the reproduction.

The present invention has been developed in view of the above, and provides a disk player that eliminates the above drawbacks and enables playback from the playback position immediately before the pause even when the pause is released, even on a disk recorded at a constant linear velocity. The purpose is to provide.

The present invention will be explained below using an example in which the present invention is applied to an optical video disc player.

The figure is a block diagram of one embodiment of the present invention.

1 is a video disc; video disc 1
is rotated by a spindle motor 2. 3
4 is a tracking device that performs tracking, and 4 is a detector that detects a reproduced information signal. 5 is a differential amplifier (including a phase correction circuit) that generates a tracking error signal from the signal obtained from the detector 4; 6 is a loop switch that opens and closes the tracking loop; the control is input from an external circuit via terminal 16; Depending on the signal, jump pulse generation circuit 8
The output signal and the tracking error signal are switched and outputted. 9 is a drive amplifier that drives the tracking device 3. Tracking device 3, detector 4, differential amplifier 5, loop switch 6, and drive amplifier 9 form a tracking servo loop.

On the other hand, 10 is a detection circuit that detects one revolution of the spindle motor 2, and includes, for example, a Hall element and a magnet.
Or it consists of a generator, etc. Reference numeral 11 denotes a flip-flop which is set by the output pulse of the spindle motor 2 for each revolution output from the detection circuit 10, and 12 performs an AND operation between the vertical synchronizing signal input from the terminal 13 and the output pulse of the flip-flop 11. 14 is a monostable multivibrator triggered by the output of the gate circuit 12. The trailing edge of the output pulse of the monostable multivibrator 14 resets the flip-flop 11, and the trailing edge of the output of the monostable multivibrator 14 causes the CLV jump circuit 15 to generate a trigger pulse.

Reference numeral 16 denotes a switching circuit, which switches the CLV jump circuit 15 when a signal from the gate circuit 19 which performs an AND operation on the CLV signal input to the terminal 17 and the pause signal input to the terminal 18 is input. When the signal from the gate circuit 19 is not input, the signal input to the terminal 20 is output. Jump pulse generating circuit 8 generates a predetermined jump pulse depending on the number and polarity of jump commands input via switching circuit 16.

In addition, 21 is a spindle servo device,
The horizontal synchronizing signal in the reproduced video signal read from the video disk 1 is compared with the oscillation output of the reference oscillator, and the error signal is used to control the spindle motor 2.
control the rotation speed. 24 is a drive amplifier that inputs the output of the spindle servo device 21 through the switching circuit 22 to drive the spindle motor 2;
23 is a low-pass filter which inputs the output of the spindle servo circuit 21 and outputs its DC component. This DC component output is passed through a switching circuit 22 that is switched by the output of the AND gate 19.
The output of the AND gate 19 is input to the drive amplifier 24 to keep the spindle motor 2 free running.

In this embodiment configured as described above, in the case of a disk (CAV disk) on which signals are recorded at a constant angular velocity, the switching circuit 16 is switched to the terminal 20 side to which the CAV jump signal is supplied, and the CLV jump signal is The output signal from signal generation circuit 15 has no effect.

Next, in the case of a disk on which video signals are recorded at a constant linear velocity, when the pause switch is turned on, the input signals at terminals 17 and 18 are both active, the AND gate 19 generates an output, and the switching circuit 16 outputs CLV. The signal is switched to the jump signal generation circuit 15 side. At this time, one output pulse is generated from the detection circuit 10 for each rotation of the spindle motor 2, and the flip-flop 11 is set by this output pulse. Therefore, in the flip-flop 11, the output of the set and the vertical synchronizing signal input from the terminal 13 are input to the AND gate 12, and the input signal from the terminal 13 that first appears after the signal detected by the detection circuit 10 is detected. A monostable multivibrator 14 is triggered at the edge. At the trailing edge of the output pulse of the monostable multivibrator 14, the CLV jump signal generating circuit 15 is triggered and the flip-flop 11 is set at the same time as generating the CLV jump signal.

Therefore, during the period from the input of the pause signal to the end of the pause signal, a CLV jump signal is generated every time the first vertical synchronization signal arrives after the detection circuit 10 generates an output.

This CLV jump signal passes through the switching circuit 16 and acts on the jump pulse generation circuit 8 to generate a jump pulse. Jump pulse generation circuit 8
The jump pulse is set so that the tracking mirror returns by a predetermined track (for example, one track).

This jump pulse is amplified by the drive amplifier 9 via the loop switch 6 and is tracked by the tracking device 3.
is applied to Therefore, the tracking mirror
Despite being a CLV disk, it steps back one track per lap.

For both CLV and CAV disks, a high level control signal is applied from the terminal 16 during the period when the jump pulse is generated, and the loop switch 6 is switched from the differential amplifier 5 side to the jump pulse generator 8 side. There is.

When the loop switch 6 is switched to the jump pulse generator 8 side, the tracking mirror begins to move toward the neutral point due to its own elastic force. Since a jump pulse is input at this time, the tracking mirror returns by one track. After returning by one track, the control signal from the terminal 16 becomes low level, the loop switch 6 is switched to the differential amplifier 5 side, and the tracking servo loop is closed. At this time, when tracking is performed once, the detection circuit 10 again generates an output, and the above-described operation is repeated again.
Therefore, during the pause period, this action is repeated, and the tracking mirror servo moves back and forth for the length of the track for each rotation of the disk during the pause period.

Also, instead of jumping back one track in one lap, it may be possible to go back 10 tracks in one lap.

At this time, since the error on the time axis increases rapidly in the track after jumping back, the DC component (average value) of the output of the spindle servo device 21 is obtained by the low-pass filter 23, and this value is used during the pause command. If the spindle motor 2 is allowed to run freely by the switching circuit 22, lock-in of the time axis servo after the pause is completed becomes easy.

Note that during pause, synchronization is disrupted, so it is better to squelch the image and audio signals using a pause command.

Furthermore, if this embodiment is used to generate a plurality of distinguishable signals from the detection circuit 10 (for example, three if three frames of signals are recorded on the outer periphery of the disk), If the timing at which the pause signal is input is memorized and playback is started at that timing after the pause is released, the next image can be played back from the same image as when the pause was started.

As explained above, according to the present invention, even with a CLV disk, it is possible to maintain the tracking device on the same track, and after canceling the pause, playback can be started from approximately the same image as when the pause was started.

[Brief explanation of drawings]

The figure is a block diagram of one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Video disk, 2... Spindle motor, 3... Tracking device, 4... Detector, 5... Differential amplifier, 6... Loop switch,
8... Jump pulse generation circuit, 9... Drive amplifier, 10... Detection circuit, 11... Flip-flop, 14... Monostable multivibrator, 15...
...CLV jump circuit, 16...Switching circuit, 21
...Spindle servo device.

Claims (1)

[Scope of utility model registration request] A disk player that can play back both a disk on which signals are recorded at constant angular velocity and a disk on which signals are recorded at constant linear velocity, and in the case of a disk on which signals are recorded at constant angular velocity, it is called a constant angular velocity disk. pulse generating means for generating at least one pulse output per rotation in synchronization with the rotation of the disk when the jump signal is supplied and the signal is recorded at a constant linear velocity; A jump signal for a disk with a constant linear velocity is supplied to generate a jump signal every time an output pulse is generated, and a switching circuit is provided to switch the jump signal according to each disk, and the track to be read when the jump signal is generated is provided. 1. A disk player comprising: a tracking device that jumps back a predetermined number of tracks; and a tracking loop opening/closing means that opens the tracking loop while the tracking device is being driven by the jump signal.