JPS59154674A - Track jump circuit of video disk player - Google Patents

Abstract

PURPOSE:To attain stably and surely track jump with simple operation by setting a point of time when acceleration drive is transited to decelerating drive by a driving voltage generating circuit based on a zero cross poing obtained by a zero cross point detecting circuit. CONSTITUTION:When a jump instruction signal J is given, an accelerating voltage Vac is generated from a driving voltage generating circuit 1 and applied to a tracking actuator 2, then a head is moved from a tracking position TG to an adjacent tracking position TN. When the actuator 2 approaches a tracking position TO at the intermediate position and an output voltage of a zero cross detecting circuit 9 changes from a high level H to a low level L, the driving voltage generating circuit 1 generates a decelerating voltage Vde having opposite polarity and the level goes down gradually. Further, when an output of a characteristic approximation circuit 5 reaches zero level. the tracking actuator 2 reaches the objective tracking position TN.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a track jump circuit for a video disc player.

Conventional circuits are designed directly for the purpose of jumping pins and quads between adjacent tracks of a video A disc. For example, if a jump command is issued at a certain point during P/L/□-f, a constant drive signal is generated at the corresponding]-lagging position of the Pino and Quanob to accelerate and drive the Toranoking actuator and the A tightening drive signal is generated at an intermediate position between the tracking position and the next tracking position to decelerate and drive the actuator, thereby moving the dragging position.

However, although such conventional circuits are suitable for making the pickup jump to adjacent tracks, when making multiple tracks jump to 1M, it is difficult to use a single toe, poor camp, etc. It is necessary to perform the above-mentioned jump operation, which is extremely troublesome and does not allow for stable and reliable operation.

This invention was made by focusing on these conventional problems, and it is possible to not only jump a pickup by one rank but also jump multiple trunks stably and reliably with a simple operation. An object of the present invention is to provide a track jump circuit for a video disc player that can be used to perform a track jump circuit for a video disc player.

The present invention will now be explained based on the drawings.

1. First, FIG. 1 shows an embodiment 1-7 in which a pickup (not shown) is caused to jump by one track. In the figure, numeral 1 is a drive voltage generation circuit,
This drive voltage generation circuit 1 supplies a drive voltage of 7 to the 6-actuator 2 via the switch 3 and the actuator driver 4. I'm starting to do it.

Further, this drive voltage vA is supplied to a characteristic approximation circuit 5, and this characteristic approximation circuit 5 is configured to obtain an output approximating the speed of the toe/knock actuator 2.
ing. Further, the output voltage VS of this characteristic approximation circuit 5 is supplied to a switch control circuit 6, and this switch control circuit 6 is configured to output a control signal SC for controlling the switch 3 described above.

On the other hand, the trunking actuator 2 uses a tracking two-volume system consisting of a tracking error detection circuit 7, a phase compensation circuit 8, etc. to maintain the trunking position with high accuracy during normal play. There is. 1
The lagging error Gt number TE obtained from the dragging error detection circuit 7 is supplied to the zero cross detection circuit 9, and the output voltage Vz of the zero cross detection circuit 9 is equal to the output voltage Vz of the driving voltage generation circuit 1. The acceleration period of the output voltage vA can be determined.

Next, the circuit operation in the above-mentioned embodiment will be explained based on the column 1 of FIG. First, Figure 2 (a
), when the di-A/knob command signal J is issued at a certain point to during play, the driving voltage generating circuit 1 simultaneously generates the accelerating voltage Vac as the driving voltage 7. The generation of this accelerating voltage Vac causes the characteristic approximation circuit 5 to operate to obtain an output voltage Vs having characteristics as shown in FIG. 2(g). When this output voltage V8 is generated, the switch control circuit 6 is activated and the output signal S of the switch 3 is activated.
C switches from the normal servo loose contact m side to the track jump contact n side (see Fig. 2 (h)). At the same time as the switch 3 is switched, the output voltage VA of the drive voltage generation circuit 1 is supplied to the acticoator driver 4, and the acceleration current Iac (Fig. 2 (e)
) is supplied to the trunking actuator 2.

In this way] - The lasogging actuator 2 has a speed characteristic (second
(see figure (f)).

In this way, the trunking actuator 2 is activated as shown in FIG.
), it moves from the dragging position To to the adjacent tracking position TN.

Therefore, the level of the tracking error signal TE obtained from the tracking error detection circuit 7 rises as shown in FIG.
-~-Ta 2 is the intermediate tracking position T.

When it approaches , it begins to descend again. When the tracking actuator 2 reaches the intermediate dragging position ftTo, the tracking error signal TE changes to zero cross L.
-U The output voltage V2t of the zero cross detection circuit 9 changes from high level H to low level L.

As a result, the drive voltage generation circuit 1 has the previous acceleration voltage Va,
A deceleration voltage Vde having a polarity opposite to that of c is generated. Since this deceleration voltage Vde is supplied to the actuator driver 4 and the characteristic approximation circuit 5, the speed of the tracking actuator 2 and the output of the characteristic approximation circuit 5 are determined by the second
The level gradually decreases as shown by f1 in Figures (t) and (g), respectively. During this time, the previous signal level is maintained so that the output switch 3 of the switch control circuit 6 is moved to the track jump contact n side. Then, when the output of the axial approximation circuit 5 reaches zero level, the output of the switch knob control circuit 6 changes so as to move the switch 3 toward the contact m side of the servo/l/-.

In this case, as the output of the characteristic approximation circuit 5 becomes zero level, the tracking position by the tracking actuator 2 shifts to the next tracking position. During this time, the tracking error signal TE is applied to the previous tracking position T.
It changes in the form of a sine wave with one cycle extending from o to the next tracking position ff1TN. By switching the switch 3, the tracking actuator 2 can be subjected to normal servo control at its dragging position TN.

The characteristic approximation circuit 5 is a circuit designed so that its output waveform is approximately equal to the velocity waveform of the dragging actuator 2. Therefore, when the output of the characteristic approximation circuit 5 returns to the zero level, it can be considered that the speed of the tracking actuator 2 has also become zero. At this time, if the switch 3 is turned to the contact point m side of the servo lube, the dragging actuator 2 will be in a state where it has no kinetic energy -C
This makes two-bore control very easy.

Next, FIGS. 3 and 4 show an embodiment in which a jump of a plurality of tracks is performed. In addition, -)
The same reference numerals will be used for the same or equivalent constituent parts as those in the embodiment, and redundant explanation will be omitted.

In FIG. 3, reference numeral 10 denotes an edge detection circuit that detects only the rising and falling edge timing signals of the output pulse i obtained from the zero-cross detection circuit 9, and the output pulse V of this edge detection circuit 10.

- I/) is supplied to the counter 11. This counter 11 inputs the jump number setting signal JN and counts the output pulse vG by a predetermined number, and also counts the output pulse vG by a predetermined number.
- The subsequent output is supplied to the drive voltage generation circuit 1.

(If the configuration is as follows: 10), for example, if a jump of 5 tracks is to be performed, a certain point t.

As in the case described above, the accelerating voltage Vac is obtained from the drive voltage generation circuit 1 by issuing the command Shinzuki J, but the counter 11
A setting signal JN corresponding to the number of jumps of 5 is supplied to '
Since counter 1] stops counting J'
When this happens, the output level of the characteristic approximation circuit 5 increases. That is, the l-racking error signal TJ! E is shown in Figure 4 (c
), trunking actuator as shown in (d), -
The dragging position by Eta 2 is T+1'121
...Since it is obtained as a signal with a period corresponding to the change from T5, the number of edge typos is equal to half of the number of edge typos in the output pulse ■ generated during the entire jump period of the zero cross detection circuit 9. The acti-elk driver 4 is supplied with the accelerating current Iac until the counter 11 starts counting (FIG. 4(e),
(f), (g)). In other words, counter 11
The tracking actuator 2 is accelerated and driven until it counts five pulses, and after the count ends, the deceleration voltage Vde is applied from the drive voltage generation circuit 1, so the output level of the characteristic approximation circuit 5 gradually decreases until it reaches zero. When the level is reached, the racking actuator 2 reaches the target tracking position T5. In this way, normal servo control is performed at the l-ranking position T5 in the same manner as described above. The above example explains the case where five trunks are made to jump, but the same explanation applies to other numbers of tigers and jumps.
It is possible.

As explained above, according to the present invention, the number of jumps of the pickup truck can be freely selected, and the jump can be performed reliably and stably with simple operation. 1. Furthermore, since the transition from normal tracking to no-vo drive and inter-trunk jump operation can be made very smoothly, there is no problem with the various functions of the video disc player.

[Brief explanation of the drawing]

1 is a block diagram illustrating one embodiment of the present invention, FIG. 2 is a timing chart illustrating the circuit operation of FIG. 1, and FIG. 3 is a diagram illustrating another embodiment of the present invention. The block diagram to be explained, FIG. 4, is a tie ζ blow chart explaining the circuit operation of FIG. 3. 1. Drive voltage generation circuit, 2. Tracking actuator, 5. Characteristic approximation circuit, 6. Switch.
control circuit, 9...zero cross detection circuit.

Claims (2)

[Claims] (1) A drive voltage generation circuit that accelerates and decelerates the drag position between the dragging positions to be jumped by receiving a jump command signal, and the tracking by receiving the output of the drive voltage generation circuit. a characteristic approximation circuit that obtains an output that approximates the speed of the actuator; and a control circuit that switches the tracking actuator from dragging servo drive to inter-trunk acceleration/deceleration drive while obtaining the output of the characteristic approximation circuit. , During the operation period of the control circuit, the tracking position is obtained from the error amount centered on the tracking position of the eta, and detects the zero cross point of the trussogging error which has a period between adjacent tra and nogging positions. and a zero-crossing point detection circuit, wherein the drive voltage generation circuit sets a time point at which the tracking actuator is shifted from acceleration driving to deceleration driving based on the zero-crossing point obtained by the zero-crossing point detection circuit, and the characteristic A toranokujiyoung circuit for a video disc player, characterized in that the deceleration drive state of a tracking actuator is stopped by detecting that the approximation circuit output has returned to a value immediately before the start of acceleration. (2) The zero-crossing point obtained by the zero-crossing point detection circuit is determined by the signal L/
The pulse is converted into different pulses, and each edge timing of the pulse is detected and the edge timing is counted by the number of tracking positions to be jumped.
8. The video disc player according to claim 1, wherein the counting time is the time when the driving voltage generating circuit shifts from acceleration driving to deceleration driving of the tracking actuator. amplifier circuit.