JPH077515B2 - Video disc player - Google Patents

Description

TECHNICAL FIELD The present invention relates to a track jump control device for a disc player device.

BACKGROUND ART A conventional example of a track jump control device for a video disc player will be described with reference to FIG.

FIG. 4 is a block diagram showing an example of a track jump control device described in Japanese Patent Application No. 62-202441. It shows three beam spots obtained by converging a laser beam, that is, an information reading spot S ₁ and this spot. When S ₁ moves relative to the disc, a pair of preceding and succeeding tracking information detection spots S ₂ and S ₃ irradiate a recording track T of the disc from a pickup (not shown) with a positional relationship shown. To be done. Reflected beams from the disk due to these beam spots enter photoelectric conversion elements 1 to 3 incorporated in the pickup.

The photoelectric conversion element 1 is arranged so that each light receiving surface is divided into four by two straight lines which are orthogonal to each other, and is composed of four light receiving elements which are independent of each other, and the total output of these elements becomes a read RF signal. . The read RF signal is supplied to the demodulation circuit 13 and demodulated into a composite video signal. The demodulation circuit 13 supplies the composite video signal to the decoding circuit 14 and a video output terminal (not shown), and also supplies the vertical sync signal separated from the composite video signal to the jump pulse generation circuit 8. Decoding circuit 14
For demodulating the performance control information inserted in, for example, a vertical blanking portion (vertical blanking period) of the composite video signal and supplying the demodulated performance control information to the controller 11.

On the other hand, the respective outputs of the photoelectric conversion elements 2 and 3 are supplied to the differential amplifier 4 and the difference between the two outputs is detected, and the difference output is the information reading spot S ₁ in the disk radial direction from the center line of the recording track T. The tracking error signal indicates the amount of deviation.

This tracking error signal is subjected to predetermined phase compensation in the equalizer circuit 5, and then becomes one input of the adder 7 via the loop switch 6. A drive pulse (jump pulse) generated by the jump pulse generation circuit 8 is applied to the other input of the adder 7. The output of the adder 7 is applied to the tracking actuator 10 via the low frequency equalizer circuit 9. The low frequency equalizer circuit 9 includes an actuator 10
It is provided in order to increase the gain of the frequencies lower than the low-range resonance frequency f ₀ . Tracking actuator 10
During normal playing, the information reading spot S ₁ is biased in the radial direction of the disc by a direction and an amount according to the polarity and level of the applied voltage, so that the spot S ₁ accurately follows the center line of the recording track T. Will be done. The circuits 2-7, 9 and 11 form a tracking servo loop.

The jump pulse generating circuit 8 is, as shown in FIG.
A monostable multivibrator (hereinafter, simply referred to as a monostable multi) 8a and 8b to which a vertical synchronizing signal is supplied, and a drive pulse signal having a pulse width and amplitude specified by the controller 11 is generated according to the outputs of both monostable multis. It is composed of a pulse generation circuit 8c.

The controller 11 is composed of, for example, a microcomputer, and when a jump command is issued from the operation unit 12, for example, opens the loop switch 6 and opens a jump pulse having a pulse width and amplitude corresponding to the number of tracks to jump. The jump pulse generating circuit 8 is controlled so as to generate. The performance control information is referred to when controlling the track jump.

With this configuration, CAV (constant angular velocity) as shown in Fig. 6
A case where a track jump is performed during the performance of a disc to perform special reproduction will be described.

In the CAV disc, one screen (frame) composed of the first and second fields is recorded on one track, and the synchronization signals of each track are aligned in the radial direction and recorded. For example, 16H (horizontal scanning) to 18H in the vertical blanking interval,
Picture control codes, chapter number codes, etc., and performance control information, such as frame number codes, are recorded in 280H and 281H, respectively.

For example, when a triple speed reproduction is commanded from the operation unit 12, the controller 11 sequentially turns on a spindle servo, a focus servo, a tracking servo, etc., which are not shown. When each servo locks, the demodulation circuit 13 demodulates the read RF signal supplied from the light receiving element 1 and outputs a composite video signal as shown in FIG. 7 (A). Further, a vertical synchronizing signal as shown in FIG. 7B separated from the composite video signal is supplied to the monostable multis 8a and 8b. Monostable multi 8a
Generates a high level output as shown in FIG. 7C in response to the fall of the vertical synchronizing signal, and continues until before the control data portion. The monostable multi 8b generates a high level output as shown in FIG. 7D in response to the fall of the vertical synchronizing signal, and continues until before the next vertical synchronizing signal. When the pulse generation circuit 8c is supplied with a command to generate a drive pulse from the controller 11, the pulse generation circuit 8c generates a drive pulse as shown in FIG. 7 (E) in response to the fall of the outputs of both monostable multis. The tracking actuator 10 is driven by the positive portion of this drive pulse.
Is energized and braked by the negative part. The switch 6 is opened by the controller 11 while the drive pulse is being supplied. The drive pulse is transmitted to the tracking actuator via the adder 7 and the low frequency equalizer 9.
When supplied to 10, the single-track jump is performed by the drive pulse, and the single-track jump is executed twice in the vertical blanking interval to perform the normal triple speed performance. With the track jump, the level of the tracking error signal also changes as shown in FIG. 7 (F).

In this way, the timing of the track jump is appropriately controlled to enable special reproduction without affecting the reproduction screen.

By the way, in the above example, the timing for performing the track jump is determined by measuring the elapse of a certain time from the supply of the vertical synchronizing signal by the monostable multi.

However, the track jump position in the vertical blanking interval fluctuates due to variations in the timekeeping time of the monostable multi, irregular rotation of the disc, etc. May occur.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a video disc player capable of suppressing the fluctuation of the track jump position on the time axis of a composite video signal.

In order to achieve the above-mentioned object, in a video disc player which reproduces an image based on a composite video signal obtained by playing the information recording disc at a constant number of revolutions while skipping the reading tracks, Sync signal separating means for separating a sync signal, rotation synchronizing signal generating means for generating a rotation synchronizing signal at every predetermined rotation angle of the information recording disk, and integration of the rotation synchronizing signal each time the vertical synchronizing signal is supplied. And an comparing means for generating a detection signal based on a comparison result between the integrated value and a comparison reference value, and a track jumping means for jumping over a read track according to the detection signal. And

Example Hereinafter, an example of the present invention will be described with reference to the drawings.

In the block diagram of the embodiment shown in FIG. 1, the portions corresponding to those in FIG. 4 are designated by the same reference numerals, and the description of those portions will be omitted.

In FIG. 1, the demodulation circuit 13a demodulates the composite RF signal as shown in FIG. 3A from the read RF signal and supplies it to the sync signal separation circuit 13b, the decoding circuit 14 and a video output terminal (not shown). The sync signal separation circuit 13b separates the horizontal and vertical sync signals as shown in FIGS. 3A and 3B from the composite video signal and supplies them to the jump pulse generation circuit 80. When playing a CAV disc, horizontal and vertical sync signals are output corresponding to the rotation angle of the disc. The synchronization signal separation circuit 13b corresponds to the synchronization signal separation means and the rotation synchronization signal generation means.

FIG. 2 shows a configuration example of the jump pulse generation circuit 80.
The horizontal and vertical synchronizing signals are supplied to the integrating input terminal and the reset input terminal of the integrating counter 81, respectively. The horizontal sync signal may include an equivalent pulse in the equivalent pulse added portion of the composite video signal. The laminated value of the counter 81 as shown in FIG.
And 83 are supplied to the respective comparison input terminals. Comparator 82 and 83
Comparison reference values are separately supplied from the data latch circuits 84 and 85 to the respective comparison reference input terminals. The comparison reference value held by each data latch circuit is set by the controller 11a.

In addition to the functions of the conventional controller 11, the controller 11a has a function of setting and controlling an arbitrary comparison reference value in the data latch circuits 84 and 85. For example, the number V ₁ of horizontal synchronizing signals from the vertical synchronizing signal to the area between the equivalent pulse and the control data is set in the data latch circuit 82 in response to the designation of the normal triple speed reproduction mode from the operation unit 12. In the data latch circuit 83, the number V ₂ of horizontal synchronizing signals from the vertical synchronizing signal to the horizontal scanning before the next vertical blanking is set. Note that the number of scanning lines is 525 in the composite video signal of NTSC system, but for example, the number of scanning lines is 625 in the composite video signal of PAL system,
The comparison reference value (corresponding to the jump position in the vertical blanking period) is set corresponding to the type of composite video signal to be demodulated.

The comparator 82 compares the stacking value and the comparison reference value V _1, and when both values match, a first detection signal as shown in FIG. 3 (E) is generated. The comparator 83 compares the integrated value with the comparison reference value V _2, and when both values match, it generates a second detection signal as shown in FIG. 3 (F). The first and second detection signals are supplied to the pulse generation circuit 8c. The outputs of the comparators 82 and 83 are reset by supplying the vertical synchronizing signal.

The pulse generation circuit 8c generates a drive pulse having a width and amplitude designated by the controller 11 as shown in FIG. 3 (G) according to the first and second detection signals and supplies the drive pulse to the adder 7. During the supply of this drive pulse, the switch 6 is opened by the controller 11a. When the drive pulse is supplied to the tracking actuator 10 via the adder 7 and the low frequency equalizer 9, the actuator 10 is driven and the information reading spot jumps to the adjacent track. At this time, the tracking error signal output from the differential amplifier 4 is as shown in FIG. The other structure is similar to that of the circuit shown in FIG.

In this manner, by counting the horizontal synchronizing signals corresponding to the rotation angle of the disc from the supply of the vertical synchronizing signal to determine the track jump position in the vertical blanking period portion, the composite video is not affected by the irregular rotation of the disc. The position of the signal on the time axis is detected more accurately, and stable special reproduction is possible.

FIG. 3 (I) shows a drive pulse generation state when performing still image reproduction. In the still image reproduction mode, one track jump is made at the final scanning portion of the second field image which is not displayed on the TV screen. Therefore, the controller 11a sets a reference value corresponding to the jump position in one data latch circuit, and sets a command in which the comparator does not generate an output in the other data latch circuit.

FIG. 3 (J) shows the state of the drive pulse in the scan operation mode in which the composite video signal is reproduced while repeating the jump of a plurality of tracks.

When jumping a plurality of tracks such as a scan operation, the controller 11a sets the reference value of the data latch circuit so that the track jump ends before the control data portion.

In this way, the jump start timing (reference value) is set according to the width of the drive pulse. For example, the track jump start position may be set near the end of one field before vertical blanking to cause image distortion at the bottom of the playback screen, but the control information can be read reliably.
There is an advantage that the current performance address can be quickly known and the next control operation such as jumping to the target track for a shortage of tracks can be immediately made.

In the embodiment, the horizontal synchronizing signal is used as the signal synchronized with the rotation of the disk, but, for example, the PL synchronized with the rotation of the spindle motor that drives the disk to rotate.
The output pulse of the L oscillator may be used.

EFFECTS OF THE INVENTION As described above, in the video disc player of the present invention, a signal corresponding to a predetermined rotation angle of the disc such as a horizontal synchronizing signal is obtained and integrated, while a reference on the time axis of the composite video signal is obtained. The integrated value is reset by the vertical synchronization signal indicating the position, and the track jump is started when the integrated value and the reference value set corresponding to the position on the time axis of the composite video signal to be jumped match. Since it was set, there is no influence of time axis fluctuation. This is preferable because the track jump position is more accurately determined and stable special reproduction is possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
Fig. Is a block diagram showing a configuration example of the jump pulse generation circuit 80. Fig. 3 is a diagram for explaining the operation of the jump pulse generation circuit 80. Fig. 4 is a block diagram showing a conventional example.
FIG. 5 is a block diagram showing a configuration example of the jump pulse generating circuit 8, FIG. 6 is a diagram for explaining a CAV disc, and FIG. 7 is a diagram for explaining the operation of the jump pulse generating circuit 8. is there. Description of symbols of main parts 1-3 ... photoelectric conversion element 6 ... loop switch 8,80 ... jump pulse generation circuit 9 ... low-frequency equalizer circuit 10 ... tracking actuator 11, 11a ... controller 13, 13a ... … Demodulation circuit 13b …… Sync signal separation circuit

Claims (4)

[Claims] 1. A video disc player for reproducing a picture on the basis of a composite video signal obtained by playing an information recording disc at a constant number of revolutions while skipping a read track. A synchronizing signal separating means for separating a synchronizing signal, a rotating synchronizing signal generating means for generating a rotating synchronizing signal at each predetermined rotation angle of the information recording disk, and an integration of the rotating synchronizing signal each time the vertical synchronizing signal is supplied. And an comparing means for generating a detection signal based on a comparison result between the integrated value and a comparison reference value,
A video disc player comprising track jumping means for jumping over a read track in accordance with the detection signal. 2. The rotation synchronizing signal generating means comprises a horizontal synchronizing signal separating circuit for separating a horizontal synchronizing signal from the composite video signal and outputting the separated horizontal synchronizing signal as the rotating synchronizing signal. Video disc player. 3. The video disc player according to claim 1, wherein the comparison reference value is set corresponding to the number of tracks to be skipped. 4. The video disc player according to claim 1, wherein the comparison reference value is set corresponding to a signal format of the composite video signal.