JPS6124068A - Reproducing device of information signal recording disc - Google Patents

Abstract

PURPOSE:To improve the stability of system by relaxing the rise and fall of a track moving signal through an integration circuit and giving the result to a tracking coil to decrease the overshoot of a stylus. CONSTITUTION:The track movement signal from a track movement signal generating circuit 12 is fed to the tracking coil 3 while the rise and fall of it are unsharpened by the integration circuit 15. Then the track moving signal (a) extracted from the track movement signal generating circuit 12 is unsharpened more or less for the rise and fall at the integration circuit 15 and becomes a signal (c), which is fed to an adder 13, where the signal is added to a tracking error signal. Thus, the overshoot of the stylus the rise is reduced, and the servo sensitivity of the system is kept equal while using the system of oscillation with high servo sensitivity and the stability of the stylus is improved at the track movement.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an information signal recording disk reproducing device, and a method for stably moving a stylus for reproducing information signals from an information signal recording disk (hereinafter referred to as a disk) to any information signal track. The present invention relates to a playback device that is forcibly moved.

The conventional technology disk has the configuration shown in Fig. 3, where the solid line indicates the information signal track where the video signal and audio signal tube are recorded, and the broken line and the two-dot chain line indicate the information signal track for accurately tracing the information signal track with the stylus. The provided tracking control signal fPIl[P2 track, vv' respectively indicates the recording position (vertical synchronization signal period) of the tracking control signal polarity switching signal (hereinafter referred to as switching signal) fP3.

FIG. 4 shows a block diagram of a conventional stylus tracking control system of the above-mentioned disc reproducing apparatus. In the figure, a signal reproduced from a disc 1 by a stylus 2 and a pickup circuit 4 is RF multiplied by a preamplifier 5, and a tracking control signal r is sent by a low-pass filter 6.
Only p+ and rρ2 are taken out, and tracking control signals rp1. rp2 is isolated. On the other hand, the polarity switching signal generation circuit 9 outputs a switching signal fp3 (
During normal playback, a signal whose H level and L level are alternately inverted each time the disk 1 rotates, while when moving a track, a signal whose polarity traces the destination track is extracted. , switch 10 is switched. As a result, the tracking control signals fp+ and fp2 are alternately switched and supplied to the comparison circuit 11.

In the comparison circuit 11, tracking control signals fp+, f
pz is compared and a tracking error signal is extracted,
The track movement signal from the track movement signal generation circuit 12 is added in an adder 13, and the result is made into a drive signal by a drive circuit 14.

This drive signal is supplied to the tracking coil 3 of the stylus 2, and controls the amount of displacement in the tracking direction so that the stylus 2 accurately traces the information signal track, and also controls the amount of other track movement.

Note that when the switching signal fp3 is at H level (L level),
The tracking control signal fp+ is on the right side of the information signal track.
(fp2), and the tracking control signal fpz (
fp+) is located, and furthermore, the track numbers are assigned as 1, 2° 3, etc. from the outermost circumference.
It is defined that the tracking control signal fp2 (fp+) is located on the left side in odd-numbered tracks (even-numbered tracks).

In the conventional device having the above configuration, when forcibly moving the stylus 2 from the nth track to the (n+1)th track, the track movement signal generation circuit 12 outputs the track movement signal a shown in FIG. 2(A). do.

The track movement signal is composed of a positive pulse and a negative pulse, as shown in FIG. are respectively displaced toward the outer circumference of the disk 1. In this case, the positive pulse outputted later cancels out the displacement force of the stylus 2 toward the inner circumference due to the negative pulse outputted earlier. On the other hand, when moving the stylus 2 toward the outer circumference of the disk 1, a signal with a polarity opposite to that shown in FIG. The displacement force of the stylus 2 toward the outer circumferential side due to the positive pulse outputted to the stylus 2 is offset.

In response to the signal a, the stylus 2 is displaced as shown in FIG. 2(B), with a particularly large overshoot at the rising edge.

In general, the stylus tracking control system has vibrating servo characteristics with a large amount of overshoot because it is necessary to increase the servo sensitivity during normal playback. Since the stylus movement control signal has a large amplitude, servo sensitivity is not required as much.

As is clear from Figure 2 (A>), the large overshoot at the rise during forced movement is due to the high servo sensitivity of stylus 2, and the servo sensitivity of tracking is inversely proportional to the stability of the system. It is in.

Problems to be Solved by the Invention Conventional devices have the same servo sensitivity as during normal playback even during forced movement, which does not require much servo sensitivity.
In particular, there were seven problems with low stability of the system during forced movement.

In particular, it is an object of the present invention to provide a playback device that reduces the amount of overshoot of the stylus when the stylus is forced to move to a certain track, and has a highly stable system.

Means for Solving the Problems FIG. 1 shows a block system diagram of an embodiment of the apparatus of the present invention, in which the same components as in FIG. 4 are given the same numbers and their explanations are omitted. . In the figure, 12 is a track movement signal generation circuit, 15 is an integration circuit that integrates the track movement signal, 13 is an adder that adds the output of the integration circuit and the tracking error signal, and 14 is the output of the adder 13 as a drive signal. The converting drive circuit 3 is a tracking coil that displaces the stylus 2 in the tracking direction.

The track movement signal from the active track movement signal generating circuit 12 is made gentle in its rising and falling edges by an integrating circuit 15, and then supplied to the tracking coil 3, thereby stabilizing the displacement of the stylus 2.

Embodiment In FIG. 1, the track movement signal a (FIG. 2(A)) taken out from the track movement signal generation circuit 12 is processed by the integrating circuit 15 to have its rising and falling waveforms somewhat gentler. The signal C shown in (C) is supplied to the adder 13 and added to the tracking error signal.

As a result, the stylus 2 moves as shown in FIG. 2(D).
The amount of overshoot at rise is reduced. Therefore, while using a vibrating system with high servo sensitivity, the servo sensitivity of the system can be kept the same as before, and the stability of the stylus can be improved during track movement.

The other configurations and operations are the same as those of the device shown in the fourth figure, so their explanation will be omitted.

Effects of the Invention The device of the present invention is configured to supply the track movement signal to the tracking coil through an integrating circuit with its rise and fall being gentle, so during normal playback, the servo sensitivity remains the same as in the conventional case and the stylus Only when forced to move,
It has features such as being able to reduce the overshoot amount of the stylus when reaching the target track and increasing the stability of the system.

[Brief explanation of the drawing]

1 and 2 are a block system diagram and a timing chart for explaining the operation of a first embodiment of the device of the present invention, FIG. 3 is a schematic diagram of an information signal recording disk, and FIG. 4 is a block diagram of an example of a conventional device. It is a system diagram. DESCRIPTION OF SYMBOLS 1... Information signal recording disk (disc), 2... Stylus, 3... Tracking coil, 7.8... Tank circuit, 9... Polarity switching signal generation circuit, 10...
Switch, 11...Comparison circuit, 12...Track movement signal generation circuit, 13...Adder, 14...Drive circuit, 15...Integrator circuit. \＋＋＋. Figure 2 Makiro → Figure 4

Claims (1)

[Claims] When forcibly displacing the stylus from one track of the information signal track spirally provided on the information signal recording disk to another track, a track movement signal composed of successive pulses of different polarities is sent to the tracking coil of the stylus. An information signal recording disk reproducing apparatus provided with a function of supplying an information signal, characterized in that the track movement signal is passed through an integrating circuit so that its rise and fall are gentle, and then the information signal is supplied to the tracking coil. Recording disc playback device.