JPH06350955A - Video disk player - Google Patents

Abstract

PURPOSE:To attain fine scanning reproduction from a video disk by replacing a noise signal with a just preceding video signal. CONSTITUTION:Reproduction at a higher speed is attained more than that at standard reproduction by applying track jump to lots of tracks every time a video signal for a predetermined field number is reproduced continuously. A video signal S14W reproduced before one or two field periods from the track jump among reproduced video signals is written in a memory 41. The video signal S14W written in the memory 41 is read for a period when track jump is executed. The read video signal S14W is outputted in place of a video signal from a video disk VD for the period when track jump is executed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to video disc players.

[0002]

2. Description of the Related Art In an optical video disc, for example, an NTSC color video signal (composite color video signal) is converted into an FM signal and the FM signal is recorded as a spiral optical track.

The recording formats at that time include a CAV format and a CLV format. When the video disc is of the CAV format, two fields of video signals are recorded on one track, and the angular position of the vertical synchronization signal recorded on the disc is the same on all tracks, and the same diameter is used. Lined up.

Therefore, when the video disk is in the CAV format, even if the optical head makes a track jump, the phase of the vertical synchronizing signal of the reproduced video signal is shifted before and after the track jump. Absent. Also, if the track jump is performed when the optical head is at the recording position in the vertical blanking period, the track jump does not affect the effective screen.

Therefore, during reproduction, for example, by repeating the reproduction of one track and the track jump of a large number of tracks alternately, scan reproduction (high-speed reproduction) can be realized.

[0006]

However, in order to perform the scan reproduction at a practical speed, the reproduction speed needs to be about 30 times as high as that in the standard reproduction. For that purpose, one track jump is required. Need to do a track jump of dozens of tracks.

However, when a large number of track jumps are performed in this way, it takes about 2 to 6 msec to perform the track jump due to the mechanical inertia of the optical head, and the time required for the track jumps. Exceeds the length of the vertical blanking period.

Therefore, when scan reproduction is performed, a video signal dropout period (noise signal period) occurs before or after the vertical blanking period, and the signal dropout occurs at the upper or lower part of the playback screen. A noise bar is generated.

The present invention is intended to solve such a problem.

[0010]

Therefore, in the present invention, when the reference numerals of the respective parts correspond to the embodiments described later, the video signal is reproduced from the video disc VD in which the video signal is recorded in the CAV format. In the video disc player, each time the video signal is continuously reproduced by a predetermined number of fields, a large number of tracks are track-jumped to perform reproduction at a speed higher than that of standard reproduction. Of these, the video signal S14W reproduced two field periods or one field period before the track jump is written in the memory 41, and the video signal S14W written in this from the memory 41 is recorded during the track jump period. Read out to TX, this read out video signal S14W
Is output in place of the video signal from the video disk VD during the track jump period TX.

[0011]

In the period TX in which the track jump is performed, the video signal reproduced from the video disk VD becomes a noise signal, but this noise signal is replaced by the video signal S14W written in the memory 41, and the noise bar is generated. A clean scan playback screen is played.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, VD indicates an optical video disc. On this disc VD, for example, an NTSC color video signal SNT is converted into an FM signal SFM, and the FM signal SFM is converted into the above-mentioned signal. As described above, it is recorded in the CAV format as a spiral optical track.

In the standard reproduction mode, the disk VD is rotated by the spindle motor 21 at a predetermined rotation speed, and the optical head 11 reproduces the FM signal SFM from the disk VD. Then, the reproduced signal SFM is supplied to the FM demodulation circuit 12 to demodulate the video signal SNT, and the signal SNT is converted into the A / D converter 1
3 and A / D converted into a digital video signal S13. In this case, as an example, the sampling frequency of the signal S13 is four times the color sub-carrier frequency, and one sample is 8 bits.

Then, the digital video signal S13 is
The video signal S which is supplied to the TBC 14 and whose time axis is corrected
14 and the signal S14 is a switch circuit 15 to be described later.
Is supplied to the D / A converter 16 through D / A conversion to the original analog video signal SNT, and this signal SNT
Is taken out to the terminal 17.

Further, a frequency generator 22 is provided directly connected to the spindle motor 21, an alternating signal S22 having a frequency corresponding to the rotation speed of the disk VD is taken out, and this signal S22 is supplied to the spindle servo circuit 23.

Further, a reference horizontal synchronizing signal REFFH having a reference horizontal frequency and a reference vertical synchronizing signal REFVD having a reference vertical frequency are extracted from the master forming circuit 31,
These signals REFFH and REFVD are supplied to the servo circuit 23. Further, the video signal SNT from the demodulation circuit 12 is supplied to the sync separation circuit 24 to extract the horizontal sync signal PBFH and the vertical sync signal PBVD, and these signals PBFH and PBVD are supplied to the servo circuit 23.

The output of the servo circuit 23 is the motor 2
1, the servo circuit 23 servo-controls the rotation of the disk VD as follows. That is, when the rotational speed of the disk VD is out of the specified value, for example, ± 20%, such as when the player is switched from the stop mode to the reproduction mode, the voltage obtained by discriminating the frequency of the signal S22 and the predetermined reference voltage are The voltages are compared, and the comparison output is supplied to the motor 21 to bring the rotation speed of the disk VD close to a specified value.

When the rotation speed of the disk VD is within ± 20% of the specified value, the reproduction horizontal synchronizing signal PBFH and the reference horizontal synchronizing signal REFFH are phase-compared, and the comparison output is supplied to the motor 21 to output the disk. The rotation speed of VD is brought close to the specified value.

In this way, the rotation speed of the disk VD is controlled by the servo control using the output signal S22 of the frequency generator 22 and the servo control using the reproduction horizontal synchronizing signal PBFH to be a prescribed rotation speed.

At this time, the reproduction vertical synchronizing signal PBVD
And the reference vertical synchronization signal REFVD are phase-compared, and the comparison output is supplied to the motor 21 to control the rotation phase of the disk VD, and the reproduction vertical synchronization signal PBVD is made in phase with the reference vertical synchronization signal REFVD.

Further, the optical head 11 is supported by the sled feed mechanism 25, and a head feed signal is supplied from the servo circuit 26 to the feed mechanism 25 to cause the head 1 to move.
The position of one disk VD in the radial direction is controlled. Further, a tracking signal is supplied from the servo circuit 26 to a tracking coil (not shown) of the head 11 to perform tracking servo of the head 11,
Are controlled to correctly scan the tracks of the disk VD.

The above is the operation in the standard reproduction mode.

When the scan reproduction key is pressed in the standard reproduction mode, the scan reproduction is executed at the signal timing shown in FIG. 2 and the noise bar-free video signal SNT is output. .

That is, when the forward or reverse scan reproduction key is pressed at an arbitrary time point, the system control microcomputer 32 causes the servo circuit 26 to operate.
Is controlled and a predetermined head feed signal is supplied from the servo circuit 26 to the sled feed mechanism 25, and the head 11 drives the disk VD at a speed of, for example, 30 times that in the standard reproduction mode.
Can be moved in the radial direction.

Further, the servo circuit 2 is controlled by the microcomputer 32.
6 is controlled, and from the servo circuit 26, for example, as shown in FIG.
As shown in B, the track jump pulse MTJ is output every four field periods. In this case, this pulse M
TJ is located immediately before the reference vertical sync signal REFVD,
Therefore, it is located immediately before the reproduction vertical synchronizing signal PBVD. Then, this pulse MTJ is applied to the head 11
Is supplied to the tracking coil of the track jumper, and a track jump of, for example, 58 tracks is performed.

Therefore, the head 11 alternately executes the reproduction of the FM signal SFM in the continuous four field period and the track jump of 58 tracks, so that the reproduced FM signal SFM of the head 11 has a time axis fluctuation. If not, as shown in FIG. 2C (the number indicates the original field number), the reproduced FM signal SFM has a continuous field number for every four field periods and 58 tracks for every four field periods. The signal of the field number is obtained by jumping for 116 field periods corresponding to.

Further, as indicated by the diagonal lines in FIG. 2C, the track jump is performed during the joint period TX of the continuous four field period and the next continuous four field period. The FM signal SFM is taken out as the noise signal SX by the track jump.

The noise period TX is 2 to 6 msec as described above, and the noise signal SX of the noise period TX causes a noise bar at the upper or lower part of the reproduction screen (effective screen).

From the head 11, such an F
Since the M signal SFM is reproduced, from the TBC14, as shown in FIG.
As shown in C, the digital video signal S14 continues for 4 field periods, and every 4 field periods,
The signal of the contents jumped for 116 field periods is output. That is, the video signal S14 is continuously output for four field periods every 120 field periods.

The video signal S14 is supplied to the switch circuit 15 and the memory 41.

Further, the write signal WRT as shown in FIG. 2D is supplied from the microcomputer 32 to the memory 41. That is, when a period having a length equal to the maximum length of the noise period TX is set as a period TW at a time position separated by two field periods from the noise period TX, a signal for permitting writing to the memory 41 is provided for each period TW. WRT is supplied to the memory 41. Therefore, as shown in FIG. 2E, the signal S14
Among them, the signal S14W in the period TW is written in the memory 41.

Further, as shown in FIG. 2F, the microcomputer 32
From the memory 41 to the memory 41 for each noise period TX.
Is supplied with a signal RD for permitting the reading. Therefore, as shown in FIG. 2G, at the noise period TX, the signal S14W written in the period TW immediately before the noise period TX is read from the memory 41.

Then, the read signal S14W is
It is supplied to the delay circuit 42, which will be described later, and is supplied for two sample periods (
It is supplied to the switch circuit 15 after being delayed by the clock period. Further, a control signal is supplied from the microcomputer 32 to the switch circuit 15, so that the switch circuit 15 receives the noise period T.
During the period excluding X, it is connected as shown in the figure and noise period TX
Is connected in the opposite state of the figure.

Therefore, as shown in FIG. 2H, the switch circuit 15 outputs T during the period excluding the noise period Tx.
Since the video signal S14 from the BC 14 is taken out and the video signal S14W from the delay circuit 42 is taken out in the noise period TX, the noise signal SX in the noise period TX is replaced from the terminal 17 by the video signal S14W. The video signal SNT will be obtained.

In this case, since the writing period TW and the noise period TX are separated by two field periods, if the noise signal SX of the period TX is directly substituted by the video signal S14W of the period TW, it is obtained at the terminal 17. Video signal S
In NT, the phase of the carrier color signal in period TX is 180 °
It means that it is reversed.

Therefore, in this example, the video signal S14W from the memory 42 is delayed by the delay circuit 42. That is, in the A / D converter 13, A / D conversion is performed at a frequency that is four times the color sub-carrier frequency,
Since 180 ° of the carrier color signal corresponds to 2 sample periods,
In the delay circuit 42, the signal S14W is delayed by two sample periods to be delayed by 180 ° before being supplied to the switch circuit 15 and used as a signal that complements the noise signal SX.

In this way, according to the example of FIG. 1, the video signal SNT continuous for four field periods every 120 field periods is output to the terminal 17, that is, scan reproduction can be performed. Then, during the scan reproduction, the video signal S14 reproduced by the track jump.
Even if the noise signal SX is included in the
Is replaced with the video signal S14W of two field periods before, a clean scan reproduction screen can be obtained without generating a noise bar at the upper or lower part of the reproduction screen during scan reproduction.

Moreover, the actual video disc player is not limited to the CAV format video disc.
The memory 4 is constructed so that a CLV format video disk can also be played back and requires a memory for special playback of the CLV format video disk.
It is not necessary to prepare a dedicated memory as 1.

Even if special reproduction is not performed and therefore there is no special reproduction memory, the memory 41 is not used.
Is a low cost, which requires a small capacity corresponding to the longest period of the noise period TX, that is, about 6 msec.

Further, when the video disc VD is a video disc on which a video signal of the MUSE system is recorded,
Since a memory is needed to fix the frame phase of the reproduced MUSE video signal to the MUSE decoder and supply it to the MUSE decoder, the memory can be used as the memory 41, so that the cost does not increase.

Further, when the noise signal SX is substituted by the video signal S14W, if the video signal of one field period is substituted, the phase of the carrier color signal must be corrected by 90 °, and the horizontal synchronizing signal and the vertical synchronizing signal are required. It is also necessary to correct the phase relationship with
In FIG. 1, the video signal S14 two fields before
Since W is used as a substitute, it is only necessary to invert the phase of the carrier color signal, and it is not necessary to correct the phase relationship between the horizontal synchronizing signal and the vertical synchronizing signal, so the configuration is simple.

For example, the delay circuit 42 can be formed by a cascaded two-stage D flip-flop circuit. Alternatively, if the reading of the video signal S14W from the memory 41 is delayed by two sample periods, the delay circuit 4
2 can be omitted.

In the example shown in FIG. 3, the noise period TX
This is a case where the noise signal SX of No. 2 is complemented by the normal video signal S14W, and only the noise signal SX before and after the vertical synchronizing signal PBVD in the period TX is complemented by the normal video signal S14W.

That is, the video signal S from the TBC 14
14 is supplied to the switch circuit 15. In addition, FIGS.
As shown in FIG.
The write signal WRT is supplied in a period excluding the period TV of the vertical synchronization signal REFVD in W, and as shown in FIG. 4E, in the period TW of the video signal S14 supplied to the memory 41, the period TV is changed to the period TV. The signal S14W in the excluded period is written in the memory 41.

Further, as shown in FIG. 4F, the microcomputer 3
2 to the memory 41, the read signal RD is supplied to the memory 41 during the noise period TX excluding the period TV of the vertical synchronization signal REFVD, and as shown in FIG. 4G, the signal S14W written in the memory 41 is The video signal S14W read out from the memory 41 is supplied to the switch circuit 15 through the delay circuit 42. Further, in the forming circuit 31, as shown in FIG. 4H, a digital vertical synchronizing signal REFVD is formed for each vertical synchronizing signal period TV of the noise period TX, and this signal REFVD is also supplied to the switch circuit 15.

Then, from the microcomputer 32 to the switch circuit 1
5 is supplied with a control signal, and the switch circuit 15 outputs T during the period excluding the noise period TX as shown in FIG. 4I.
The video signal S14 from the BC 14 is taken out, the video signal S14W from the delay circuit 42 is taken out during the noise period TX excluding the vertical synchronizing period TV, and the vertical synchronizing signal from the forming circuit 31 is taken out during the period TV. The signal REFVD is taken out.

Therefore, also in this example, the terminal 17
, A video signal SNT for scan reproduction is output. Since the vertical synchronizing signal REFVD of the noise period TX is formed in the forming circuit 31 during this scan reproduction, the vertical synchronizing signal PBVD at this time is stored in the memory 4 during the period TW.
Therefore, it is not necessary to write the data into the memory 1, so that the capacity of the memory 41 can be further reduced.

In the example of FIG. 3, every two field periods, that is, every one rotation of the disk VD.
A track jump can be performed. In that case, as shown in FIG. 5, the video signal S14 of the noise period TX is changed to
The video signal S14W of the period TW which is one field period before is used as a substitute, and the vertical synchronizing signal REFV is generated from the forming circuit 31.
Just insert D.

[0049]

According to the present invention, even when the noise signal SX is contained in the video signal S14 reproduced by the track jump during the scan reproduction, the noise signal SX is replaced with the immediately preceding video signal S14W. A clean scan reproduction screen can be obtained without generating a noise bar at the top or bottom of the reproduction screen during scan reproduction.

Moreover, since the actual video disc player has a memory for special reproduction of the CLV format video disc,
When D is a video disc on which a MUSE video signal is recorded, it has a memory for fixing the frame phase of the reproduced MUSE video signal to a fixed value and supplying it to the MUSE decoder. There is no need to prepare a memory dedicated to scan playback. Even if the special reproduction memory is not provided, the video signal S14W is about 6 msec in time, so the memory may have a small capacity and the cost is low.

[Brief description of drawings]

FIG. 1 is a system diagram showing an example of the present invention.

FIG. 2 is a waveform diagram for explaining the present invention.

FIG. 3 is a system diagram showing another example of the present invention.

FIG. 4 is a waveform diagram for explaining the present invention.

FIG. 5 is a waveform diagram for explaining the present invention.

[Explanation of symbols]

 11 Optical Head 12 Demodulation Circuit 14 TBC 17 Output Terminal 21 Spindle Motor 22 Frequency Generator 23 Spindle Servo Circuit 24 Sync Separation Circuit 25 Head Feed Mechanism 26 Servo Circuit 31 Master Forming Circuit 32 Microcomputer 41 Memory 42 Delay Circuit VD Video Disk

Claims (3)

[Claims] 1. A video disc player for reproducing the video signal from a video disc in which the video signal is recorded in the CAV format, and a plurality of tracks are reproduced every time the video signal is continuously reproduced by a predetermined number of fields. A track jump is performed to perform reproduction at a higher speed than in standard reproduction, and a video signal reproduced from the reproduced video signal two field periods or one field period before the track jump is stored in the memory. Write, read the video signal written in this memory from this memory during the track jump, and read the read video signal from the video disc during the track jump. Video disc designed to output instead of signal Reya. 2. The video disc player according to claim 1, wherein the track jump is performed in a period including a vertical synchronization signal of the reproduced video signal. 3. The video disc player according to claim 2, wherein when the video signal is written in the memory, a vertical synchronization signal included in the video signal is not written, and the track jump is performed. In addition, when outputting the video signal read from the memory in place of the video signal from the video disc, a separately prepared vertical synchronization signal is output in place of the video signal from the video disc. .