JPS5862837A - Disk reproducing device - Google Patents

Abstract

PURPOSE:To easily retrieve a track, by exactly counting a track position by a direction signal in case when a track reproducing signal pickup means crosses the track, and the number of times of crossing of the track. CONSTITUTION:To a terminal T1, a reproducing signal is applied, its terminal T1 is connected to an envelope detecting circuit 1, and the detecting circuit 1 is connected to one input terminal of an exclusive logical circuit 9 through a waveform shaping circuit 2, etc. On the other hand, to a terminal T2, a track error signal is applied, and an output of the terminal T2 is provided to a counting circuit 10 through a waveform shaping circuit 3, etc. In this way, once the reference of a track position is decided, a track position can be detected exactly even if eccentricity exists in a video disk, etc., and a track can be retrieved easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a track detection RE for searching playback tracks of video discs (hereinafter referred to as VD) or digital audio discs (hereinafter referred to as DAD).

VD-? In DADK, generally, a playback signal pickup means such as a playback head is freely attached to the target track.
In the place where PM@ is used, the position information once recorded on the truck is taken and the reproduced signal pickup means is moved to the truck corresponding to the desired position.
However, when playing these VD +DAD tt on the turntable of the playback station, or VD +DA
D) Due to the eccentricity that occurs when punching the center hole during manufacturing, it is eccentric by several tens to hundreds of tracks to make 1gl@-f) Rack position information + After removing the target track, it is not possible. Just pick up the playback signal! There is a need to move the truck with R, but if you move the reproduced signal pickup means slowly at this time, you will not be able to tell how many tracks have been transferred to that direction difference just by the number of times the track F signal is repeated. Eccentric shielding work 9 It was necessary to move the head in V as soon as possible. For this reason, it takes a lot of time to perform the trunk servo while shifting it from track to track, requiring a large amount of power to drive the manual pick-up of the reproduced signal, and the disadvantage is that it requires a plurality of circuits.

Essentially, M provides a disc playback device that eliminates the above-mentioned drawbacks, and its first feature is that when the track playback signal beat-up means of the disc crosses, it detects this direction; The track position is now counted accurately based on the direction signal and the number of tracks crossed.9. The above-mentioned direction signal when crossing the track, ie, track movement direction signal, is obtained from a reproduction signal obtained from the track and a track error signal.

Hereinafter, an exemplary embodiment of the present invention will be shown in Figures 1 to 5.
Please describe in detail.

FIG. 1 shows a system diagram of the present invention, in which a reproduction signal recorded on a disk is given to a terminal (T1), and the terminal (
Tl) ri-c:/Bello, P-detection printing circuit (17K
1 m m -g and m connected to one envelope detection circuit (υ is a waveform shaping circuit e). Output of waveform shaping circuit (2) ri First differentiating circuit φ2 Second AND gate circuit (
7) The -10,000 input terminal is connected to the external logic circuit (T10,000).-10,000 (Ts) is given a track error signal, and the terminal (Tz) is connected to the rt waveform shaping circuit. φ) The output of the axillary waveform shaping circuit (8) is connected to one input terminal of the first and second differential circuit (6), and the first and second The output of the flip-flop circuit (6) is connected to the set (a) and reset (R) input terminals of the flip-flop circuit (8). ) and the counter circuit (6), the load signal is given to the terminal (T3), and the terminal (T3) is connected to the counter circuit (6).
The output of 1) is given to a counter circuit (2).

The operation of the present invention configured as described above is illustrated in FIG.
This will be explained using the waveform of Seki.

The playback signal applied to the 1N terminal (Ts) K is the 11th □
1 Figure 2 (A) obtained when the DAD or map track (C) shown in Figure 2 is moved in the D1 direction & the spora from the reproduction signal pickup means (8P) is moved.
As shown in the waveform, the maximum reproduction sensitivity output is obtained at the center of the track and the minimum between the tracks.

As shown in Figure 2B, the tracking error signal (B) applied to the terminal (T) has a waveform in which the voltage changes linearly at the center of the rack (C). The servo is adjusted so that

Since a method for detecting such a tracking error signal has been proposed extensively and is public knowledge, the details thereof will be omitted, but these reproduced signals and the tracking error signal riDAD-?
Due to the eccentricity of VD, the waveforms shown in FIG. 6 (M') and (B') occur. That is, in order to perform envelope detection in the reproduced signal, an envelope detection circuit (in addition to υ) is formed with the waveform shown in FIG. 6(a).

The waveform shown in FIG. 6(a) is sliced at an average level of 1 and the waveform is shaped by the first waveform shaping circuit (2).tL#i The track reproduction signal shown in FIG. 3(o) is obtained.

If the waveform obtained in FIG. 6(b) is differentiated by the differential circuit of jll (in addition to the rising nine portions of the waveform), the differential waveform in FIG. 6(b) is obtained.

1:2y% 51st! ! In addition to the second waveform shaping circuit (3) which slices and shapes the tracking error signal 1 shown in (B') at an average level of 2', a second differentiating circuit obtains the waveform shown in FIG. 6(C). By adding it to ωλ, j [f
A waveform of f1 (8') is obtained.

The outputs of the first and second differentiating circuits (4) and (5) are given to the first and second AND gate circuits (6) and (7), as well as to the JLL AND gate circuit (6). is the second waveform! The output of Figure S (c) from the 1st form (3) and the waveform of Figure 5 (a') of the differential circuit of Ml (from 4) are manually input, so only when these waveforms are present at the same time. The waveform shown in Figure ts3 (2') is output.

In addition, the second AND GO) 1 circuit (7) has the waveform shown in Fig. 3 <a> of the first waveform shaping circuit (■) and the second differential circuit (
5) The waveform of the third waveform (in FIG. 6, where the output pulse is produced when the negative and negative outputs are simultaneously present) is obtained.

The AND gate circuit of iris 1 and [2 (output at 6 bar operates the flip-flop circuit (8) (Fig. For example, by counting the data shown in FIG. 6(b), it is possible to reliably know in which direction and how many tracks the robot has moved from the position of the predetermined value.

In the counter circuit 4, the waveform shown in FIG. 6 (b) from the first waveform shaping circuit (2) and the output of the flip-flop circuit (marked in FIG. 6 (e)) are added to the exclusive logic circuit (9). - Therefore, the waveform shown in Figure 5 (b) is counted through the exclusive/pull logic circuit (9).

The counter circuit (the output of 10 is the same as shown in Figure 6) rack area has the same count, and the predetermined value is the terminal (
T1) should be given a lower rotor signal (L).

Since the present invention is constructed and operated according to the above-mentioned knowledge, once the reference for the track position is set, the track position can be reliably detected even if there is an eccentricity in the ma A useful disc playback device

[Brief explanation of drawings]

Fig. 1 is a system diagram of the disc playback device of the present invention, Fig. 2 is a waveform diagram for explaining the playback signal and tracking error code obtained from the trunk of DAD etc. and the playback spot, and the 6th figure is the rattan figure 1. A waveform diagram is used to explain this. In the figure, U) is an envelope detection circuit, (2) (8) r
i first and second waveform shaping circuits, (4) and (5) are first and second differentiating circuits, (first and second AND gate circuits on 6 bar 7J, (8) are flip-flop circuits, (9)r
! Exclunbu logic circuit, (IQ is a counter path. Patent applicant H Hon Columbia Co., Ltd. 1 Figure 1 Figure 31

Claims (2)

[Claims] (1) The phase of both the level detection means for detecting the signal corresponding to the V bell of the reproduced signal obtained from the Tisfufu and the trunk error detection means 9 for detecting the track error No. 9 corresponding to the trunk clearance fL of the disk is detected. A disc reproducing apparatus characterized in that the direction of relative movement between the reproduction signal pickup means and the reproduction track is determined by detection. (2) The first range of relative movement of the F-track is controlled by controlling the forward/reverse direction of the track signal counter and counting the number of relative movements of the F-track based on the relative movement direction detection signal between the playback signal pickup means and the playback trunk.
゛Disc playback device for distribution.