JPH067430B2 - Conveyance control device for recording disc signal detection means - Google Patents

Description

The present invention relates to a disc-shaped recording medium such as a video disc (hereinafter,
The present invention relates to a transport control device of signal detection means for detecting a signal recorded on a disc.

2. Description of the Related Art It is known that there are various types of video discs. Here, the VHD method, which is one of the methods, will be described as an example. FIG. 2 shows a typical conventional configuration diagram regarding the transport control of the signal detection means of the VHD system player, and FIG.
FIG. 3 shows a schematic diagram of recording of an information signal, a tracking signal, an index signal and an address signal of a disc of the system. In FIG. 3, a solid line indicates an information signal track, a one-dot chain line indicates one tracking signal, a two-dot chain line indicates the other tracking signal, and a hatched portion indicates an index signal, A ₀ ,
A ₁ , A ₂ , and A ₃ are recording positions of address signals indicating positions on the disc. Reference numeral 13 is a signal detecting means, which is composed of a signal detecting section 13A for detecting a signal recorded on the disc and a signal detecting section transporting section 13B for mounting / transporting the signal detecting section 13A.

Generally, in order to cause the signal detecting means 13 to accurately scan the track of the information signal, the signal detecting portion 13A is moved to the radius of the disk so that the detection levels of the two types of tracking signals detected by the signal detecting portion 13A become substantially equal. Drive control in the direction,
In addition, the drive control direction in the radial direction is reversed at the recording position of the index signal. At this time, while the signal detection section transport section 13B is stopped, only the signal detection section 13A is driven and controlled in the radial direction of the disc, and for example, the position B ₀ → B in FIG.
_When the tracks of the information signal are scanned from the outer circumference to the inner circumference of the disc as in _one direction, the inclination of the signal detection unit 13A with respect to the signal detection unit transport unit 13B is larger at the position B ₁ than at the position B _0. Become. Since the signal detection unit 13A is limited to the movable range, when the inclination reaches the limit, it becomes impossible to accurately scan the track of the information signal. For this reason, the following means have been used to suppress the inclination of the signal detection unit 13A to the minimum, in other words, to control the signal detection unit 13A in the approximate center of its movable range.

In order for the signal detection means 13A to accurately scan the track of the information signal, the differential tracking signal which is the difference between the detection levels of the two types of tracking signals is used. To actually drive the signal detecting means 13A, the differential tracking signal is subjected to phase compensation and a tracking control signal suitable for driving is generated.

110 in FIG. 4 is a tracking control signal when the position B _{0, that} is, the inclination of the signal detecting means 13A is minimum. 111
Is a tracking control signal for the position B ₁ . It is generally known that when the inclination of the signal detector 13A changes, the DC component of the tracking control signal changes in proportion to the inclination. Therefore, the signal detector 13A is located at the position B.
_When the number reaches ₁ , the DC component of the tracking control signal changes like the signal 110 as compared with the signal 110. Therefore, it is necessary to minimize the fluctuation of the DC component, that is, the signal detection unit.
Signal detector transport section 13B so that the inclination of 13A can be minimized
Drive control. That is, as the signal detection unit 13A moves in the direction of the position B ₀ → B ₁ , the signal detection unit transport unit is proportional to the variation of the DC component of the tracking control signal.
13B is also moved in the direction of position B ₀ → B ₁ . By performing such control, it is possible to accurately scan the track of the information signal from the outermost circumference to the innermost circumference of the disc.

FIG. 2 is a transport control block diagram of a conventional typical signal detecting means having this control means.

Reference numeral 10 is a disc, 11A is a turntable on which the disc is mounted, 11B is a turntable motor that drives the turntable 11A to rotate, 12 is a turntable motor controller, and 13 is a turntable motor control unit.
Is a signal detecting means composed of the signal detecting section 13A and the signal detecting section conveying section 13B, 14 is a detecting signal amplifying section for amplifying the signal detected by the signal detecting means 13, and 15 is amplified by the detecting signal amplifying section 14. A circuit that extracts one tracking signal from the signal, similarly 16 is a circuit that extracts the other tracking signal,
Reference numeral 17 is a circuit for extracting the index signal. The differential tracking signal generator 18 generates a differential tracking signal 104 from the difference between the detection levels of the two types of tracking signals and the index signal. The phase compensator 24 performs phase compensation on the differential tracking signal and generates the tracking control signal 100 required for the signal detector 13A to accurately scan the information signal track.

19 indicates the signal detection unit 13 based on the tracking control signal 100.
A tracking control drive unit for driving A in the radial direction of the disk. The reference numeral 20 detects the DC component of the tracking control signal 100, and in proportion to the DC component, the signal detection section carrier section 13
This is a signal detection means conveyance control unit for driving and controlling B and minimizing the inclination of the signal detection unit 13A.

Problems to be Solved by the Invention The conventional technique as described above has the following problems. That is, when the signal detection unit 13A is detecting a signal from the disc 10, foreign matter such as dust may adhere to the disc 10 or the signal detection unit 13A and the signal cannot be accurately detected from the disc 10. At this time, two kinds of tracking signals or index signals cannot be detected,
As a result, the tracking control signal 100 is the curve 1 in FIG.
An abnormal signal such as 13 is generated, the signal detector 13A is largely shaken in the radial direction of the disk 10, and the inclination is largely changed. Due to the abrupt change of the inclination of the signal detection unit 13A, the DC component of the tracking control signal is the curve 11 in FIG.
As shown in FIG. 4, the signal detecting section transporting section 13B moves violently, and it becomes more difficult to detect the signal from the disc 10, and the player becomes extremely unstable.

The present invention, when foreign matter such as dust adheres to the disc or the signal detection unit and an accurate signal cannot be detected from the disc, causes an unstable movement of the signal detection unit conveyance unit due to an abnormality of the tracking control signal. The purpose is to reduce.

Means for Solving the Problems In the present invention, in order to solve the above problems, an address signal recorded on a disk is used, and if the address signal cannot be accurately detected for a certain period of time, a signal is generated. A function of suspending the use of the tracking control signal for the drive control of the detection section transporting unit and restarting the use of the tracking control signal when the address signal is detected after a predetermined time or again is added.

Effect In the present invention, by using the above means, when the accurate signal cannot be detected from the disk, the tracking control signal is not used for drive control of the signal detection section transport section, so that the signal detection section operates abnormally on the disk. Even if this is done, unstable movement of the signal detection section transport section is reduced.

Embodiment FIG. 1 is a block diagram showing an embodiment of drive control of signal detecting means in the present invention. The same components as those shown in FIG. 2 are designated by the same reference numerals. Reference numeral 21 is an address signal extracting unit that extracts an address signal from the signal amplified by the detection signal amplifying unit 14. Address signal determination unit 22
Is the address signal 103 obtained by the address signal extracting unit 21.
If the address signal 103 cannot be accurately detected for a certain period of time, the tracking control signal switching signal 101 is output as shown in FIG. It has a function to control not to input.

The tracking control signal switching unit 23 receives the instruction of the tracking control switching signal 101, prohibits the sending of the tracking control signal 100 to the signal detection means conveyance control unit 20, and the tracking control signal 100 during this period when the sending is prohibited. Instead of delivering a constant voltage. That is, the switching unit 23 generates the correction tracking control signal 102 so that the signal detection unit transport unit 13B does not operate in an unstable manner. In FIG. 6, the time for determining whether or not the address signal can be accurately detected by the address signal determining section 22 is the signal detecting section transport section 13B after the abnormality of the tracking control signal occurs.
It is preferable to set the time shorter than the time until the unstable movement is performed. Further, when the address signal is detected again as shown in FIG. _6C01 , the tracking control signal 100 is controlled to be input again to the signal detection means conveyance control section 20, and the conveyance of the signal detection conveyance section 13B is stably performed. Get control. In the present embodiment, the case of the VHD system has been described, but even in the case of other systems, it is similarly effective when carrying the transport control of the signal detecting means by using the tracking signal.

The example of restarting the use of the tracking signal on condition that the address signal is detected after the use of the tracking signal is interrupted has been explained, but the method of restarting the use after a certain time has elapsed after the interruption, or the error display and the reading is interrupted. It is also possible to do it.

As described above, according to the present invention, even if the signal detection unit 13A cannot detect the tracking signal from the disc for a certain period of time, the signal detection unit transport unit 13B does not move unstablely and is stable. It becomes possible to control.

[Brief description of drawings]

FIG. 1 is a block diagram showing control of a signal detecting section conveying section in one embodiment of the present invention, and FIG. 2 is a block diagram showing control of a conventional representative signal detecting section conveying section. Figure 3 shows VHD
FIG. 4 is a schematic diagram of recording of tracking signal, index signal and address signal of a disc of the method, FIG. 4 is a waveform diagram of an essential part of FIG. 3, FIG. 5 is a waveform diagram of an essential part of FIG. 2, and FIG. FIG. 3 is a waveform diagram of a main part of FIG. 1. 13 ... Signal detecting means, 13A ... Signal detecting section, 13B ... Signal detecting and conveying section, 18 ... Differential tracking signal generating section, 19
...... Tracking control drive unit, 20 ...... Signal detection means conveyance control unit, 21 ...... Address signal extraction unit, 22 ...... Address signal determination unit, 23 ...... Tracking control signal switching unit, 24 ......
Phase compensation section, 100 ... Tracking control signal, 101 ... Tracking control signal switching signal, 102 ... Corrected tracking control signal, 103 ... Address signal

Claims (2)

[Claims] 1. An information signal recorded concentrically or spirally on a disk-shaped recording medium, a tracking signal for accurately operating a track of the information signal, and an address signal indicating a position on the recording disk. A conveyance control device of a signal detection means for detecting, using the tracking signal,
Means for causing the signal detecting means to accurately scan the track of the information signal, and means for carrying the signal detecting means,
A recording disk signal detecting means for monitoring the address signal, and interrupting the use of the tracking signal for carrying control of the signal detecting means when the address signal cannot be read for a predetermined time. Transport control device. 2. An information signal recorded concentrically or spirally on a disk-shaped recording medium, a tracking signal for accurately operating a track of the information signal, and an address signal indicating a position on the recording disk. A conveyance control device of a signal detection means for detecting, using the tracking signal,
Means for causing the signal detecting means to accurately scan the track of the information signal, and means for carrying the signal detecting means,
A means for monitoring the address signal and interrupting the use of the tracking signal for carrying control of the signal detecting means when the address signal cannot be read for a predetermined time, and the signal detecting means for detecting the address signal after interruption. And a means for restarting the use of the tracking signal for the transport control of the recording disk signal detecting means.