JPH02267737A - Video disk player - Google Patents

Abstract

PURPOSE:To accurately discriminate a track jump position by controlling a jump pulse based on a comparison of an integrated value of a horizontal synchronizing signal separated from its rotary synchronizing signal with a set value. CONSTITUTION:A composite video signal read out of a video disk by a photoelectric transducer 1 is demodulated 13a, and the horizontal synchronizing signal H and vertical synchronizing signal V are separated from the rotary synchronizing signal by a synchronizing signal separating circuit 13b to be supplied to a jump pulse generating circuit 80. Then, the integrated value of the signal H to be reset by the signal V is compared with a set number of jumps via a controller 11a, and upon coincidence, the jump pulse is controlled to be finished. By this constitution, the track jump position is accurately decided without being influenced by a time base variation of the composite video signal, thus performing always the accurate track jump.

Description

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

BACKGROUND ART A conventional example of a track jump control device for a video disc player will be explained 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, and shows three beam spots obtained by converging a laser beam, namely an information reading spot S1 and this spot S1. When moving relative to the disk, a pair of preceding and succeeding tracking information detection spots S2 and S3, respectively, are irradiated from a pickup (not shown) onto a recording track T of the disk with the positional relationship shown. The beams reflected from the disk by these beam spots are transmitted to the photoelectric conversion element 1 built in the pickup.
~3.

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

On the other hand, each output of the photoelectric conversion elements 2 and 3 is supplied to a differential amplifier 4 to detect the difference between the two outputs, and this difference output is determined by the deviation of the information reading spot S1 in the disk radial direction from the center line of the recording track T. It becomes a tracking error signal indicating the amount.

This tracking error signal is subjected to a predetermined phase compensation in the equalizer circuit 5, and then passes through the loop switch 6 and becomes the output of the adder 7. A drive pulse (jump pulse) generated by a jump pulse generation circuit 8 is applied as the external power to the adder 7. The output of the adder 7 is applied to a tracking actuator 10 via a low frequency equalizer circuit 9. The low-frequency equalizer circuit 9 is provided to increase the gain of frequencies below the low-frequency resonance frequency fo of the actuator 10. During normal performance, the tracking actuator 10 biases the information reading spot St in the radial direction of the disc by a direction and amount depending on the polarity and level of the applied voltage, and from this, the spot S1 is located on the center line of the J-edge track T. will be followed accurately. Circuits 2-7.9 and 11 form a tracking servo loop.

The jump pulse generation circuit 8, as shown in FIG.
Monostable multivibrator supplied with vertical synchronization signal (
(hereinafter simply referred to as a monostable multi) 8a and 8b, and a pulse generating circuit 8C that generates a drive pulse signal having a pulse width and amplitude specified by the controller 11 in accordance with the outputs of the monostable multi.

The controller 11 is constituted by, for example, a microcomputer, and when a jump command is issued from the operation unit 12, it opens the loop switch 6 and generates a jump pulse with a pulse width and amplitude corresponding to the number of tracks to be jumped. The jump pulse generating circuit 8 is controlled to generate the jump pulse. Performance control information is referred to when controlling track jumps.

With this configuration, a case will be described in which special playback is performed by performing a track jump during the performance of a CAV (constant angular velocity) disc as shown in FIG.

In a CAV disc, one screen (frame) consisting of first and second fields is recorded on one track, and synchronization signals of each track are recorded in alignment in the radial direction. For example, 16H (horizontal scanning) to 18 of the vertical blanking section
A picture stop code, a chapter number code, etc. are recorded in H, and performance control information such as a frame number code is recorded in 280H and 281H, respectively.

When, for example, triple speed playback is commanded from the operation unit 12, the controller 11 sequentially turns on the spindle servo, focus servo, tracking servo, etc. (not shown). When each servo is locked, the demodulation circuit 13 demodulates the read RF multiplied 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. 7(B) separated from the composite video signal is supplied to the monostable multiplexers 8a and 8b.

The monostable multi 8a generates a high level output as shown in FIG. 7(C) 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. 7(D) in response to the fall of the vertical synchronizing signal, and continues until 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, it generates a drive pulse as shown in FIG. 7(E) in response to the fall of the output of the both vehicle stabilization multiplier. The tracking actuator 10 is energized by the positive part of this drive pulse, and braked by the negative part. The switch 6 is kept open by the controller 11 while the drive pulse is being supplied. When such a drive pulse is supplied to the tracking actuator 10 via the adder 7 and the low-frequency equalizer 9, a single track jump is performed by the drive pulse, and two single track jumps are performed in the vertical blanking section, resulting in a positive 3 It is played at double speed. As the track jump occurs, the level of the tracking error signal also changes as shown in FIG. 7(F).

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

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

However, due to variations in the clocking time of the monostable multi or uneven rotation of the disk, fluctuations occur in the track jump position in the vertical retrace section, resulting in loss of equivalent pulses and control data in the demodulated composite video signal, disturbances in the playback screen, etc. This may occur.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a video disc player that can suppress fluctuations in track jump positions on the time axis of a composite video signal.

In order to achieve the above object, in a video disc player that plays an information recording disc at a constant rotation speed while skipping the read track to obtain a composite video signal and reproduce images based on this, a vertical synchronization signal separation means for separating synchronization signals; rotation synchronization signal generation means for generating a rotation synchronization signal every predetermined rotation angle of the information recording disk; and integration of the rotation synchronization signal each time the vertical synchronization signal is supplied. The present invention is characterized by comprising an integrating means for repeating the above, a 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 the read track in response to the detection signal. shall be.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

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

In FIG. 1, the demodulation circuit 13a has a third
A composite video signal as shown in FIG. 3A is demodulated and supplied to the synchronizing signal separation circuit 13b, the decoding circuit 14, and a video output terminal (not shown). The synchronization signal separation circuit 13b separates horizontal and vertical synchronization 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 synchronization signals are output corresponding to the rotation angle of the disc. The synchronization signal separation circuit 13b corresponds to synchronization signal separation means and rotation synchronization signal generation means.

FIG. 2 shows a configuration example of the jump pulse generation circuit 80. The horizontal and vertical synchronization signals are supplied to the integration input terminal and reset input terminal of the integration counter 81, respectively. In addition,
The horizontal synchronization signal may include an equivalent pulse in the equivalent pulse added portion of the composite video signal. The integrated value of the counter 81 as shown in FIG. 3(D) is supplied to the comparison input terminals of the comparators 82 and 83, respectively. Comparison reference values are separately supplied from data latch circuits 84 and 85 to comparison reference input terminals of comparators 82 and 83, respectively. The comparison reference value held by each data latch circuit is set by the controller lla.

In addition to the various functions of the conventional controller 11, the controller lla has an additional function of setting and controlling arbitrary comparison reference values in the data latch circuits 84 and 85. For example, the number V1 of horizontal synchronization signals from the vertical synchronization signal to the area sandwiched between the equivalent pulse and the control data is set in the data latch circuit 82 in response to the specification of the normal triple speed playback mode from the operation unit 12, The number v2 of horizontal synchronization signals from the vertical synchronization signal to the horizontal scan before the next vertical blanking is set in the data latch circuit 83. Note that an NTSC composite video signal has 525 scanning lines, but a PAL composite video signal has 625 scanning lines, so the comparison reference value (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 integrated value and the comparison reference value V1, and when both values match, generates a first detection signal as shown in FIG. 3(E). The comparator 83 compares the integrated value and the comparison reference value v2, and when both values match, generates a second detection signal as shown in FIG. 3(F). The first and second detection signals are supplied to a pulse generation circuit 8C. The outputs of comparators 82 and 83 are reset by the application of a vertical synchronization signal.

The pulse generating circuit 8C responds to the first and second detection signals,
The third width and amplitude specified by the controller 11
A driving pulse as shown in FIG. 3(G) is generated and supplied to the adder 7. During the supply of this drive pulse, the switch 6 is opened by the controller lla. 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. 3(H). The other configurations are similar to the circuit shown in FIG.

In this way, by counting the horizontal synchronization signal according to the rotation angle of the disk from the supply of the vertical synchronization signal and determining the track jump position in the vertical retrace period, composite processing is performed without being affected by uneven disk rotation. The position of the video signal on the time axis can be detected more accurately and stable special playback can be performed.

FIG. 3(1) shows a state in which drive pulses are generated when still images are reproduced. In the still image reproduction mode, one track jump is made in the last scanned portion of the second field video that is not displayed on the television screen. Therefore, the controller lla sets a reference value corresponding to the jump position in one data latch circuit, and sets a command for the comparator not to generate an output in the other data latch circuit.

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

When performing a jump of multiple tracks such as a scanning operation, the reference value of the data latch circuit is set by the controller lla 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 1 field before vertical blanking, causing image disturbance at the bottom of the playback screen, but the control information can be reliably read and the current playing There is an advantage that the address can be quickly known and the next control operation, such as jumping to the target track by the amount of missing track, can be immediately carried out.

In the embodiment, a horizontal synchronization signal is used as a signal synchronized with the rotation of the disk, but for example, a P signal synchronized with the rotation of a spindle motor that rotationally drives the disk is used.
The output pulse of the LL oscillator may also be used.

As described in detail, in the video disc player of the present invention, signals corresponding to a predetermined rotation angle of the disc, such as a horizontal synchronization signal, are obtained and integrated, while the time axis reference of the composite video signal is The accumulated value is reset by a vertical synchronization signal indicating the position, and the track jump is started when the accumulated value matches a reference value set corresponding to the position on the time axis of the composite video signal to be jumped. This is preferable because there is no influence of time axis fluctuations, the track jump position can be determined more accurately, and stable special playback is possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration example of a jump pulse generation circuit 80, and FIG. 3 is 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 generation circuit 8, FIG. 6 is a diagram for explaining a CAV disk, and FIG. 1 is a diagram for explaining the operation of jump pulse generation circuit 8. FIG. Explanation of symbols of main parts 1 to 3...Photoelectric conversion element 6...Loop switch 8.80...Jump pulse generation circuit 9...
...Low frequency equalizer circuit 0...Tracking actuator 1, lla
River stiffness controller 13a...Demodulation circuit 3b...Synchronization signal separation circuit

Claims (4)

[Claims] (1) A video disc player that plays an information recording disc at a constant rotation speed while skipping reading tracks to obtain a composite video signal, and reproduces images based on the composite video signal, which generates a vertical synchronization signal from the composite video signal. a rotation synchronization signal generating means for generating a rotation synchronization signal every predetermined rotation angle of the information recording disk, and repeating the integration of the rotation synchronization signal each time the vertical synchronization signal is supplied. an integrating means; a 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 read tracks in response to the detection signal. (2) The rotation synchronization signal generating means comprises a horizontal synchronization signal separation circuit that separates a horizontal synchronization signal from the composite video signal and outputs it as the rotation synchronization signal. 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 in accordance with the signal format of the composite video signal.