JPS6037733Y2 - Recording disc playback device - Google Patents

Description

[Detailed explanation of the idea] This invention relates to a recording disk reproducing device.

In recent years, video signal information and the like are recorded on a rotating disc-shaped recording medium, a so-called recording disc, which is placed on a turntable and rotated, while a reproducing element is traced along the information track to record the video signal information, etc. A recording disc playback device has been developed that detects and plays video signals and the like.

There are two methods of rotating a recording disk (hereinafter referred to as a video disk) on which video signal information is recorded: a method of keeping the angular velocity constant and a method of keeping the linear velocity constant.

If the recording density of a video disc is limited, the amount of information that can be recorded on a single video disc is greater with the latter method.

FIG. 1 shows a conventional example of a recording disk reproducing apparatus that detects signal information while keeping the linear velocity constant.

That is, the signal information detecting section 13 detects signal information from the video disc 12 placed on the turntable 11 and rotating.

Note that video signals and audio signals are generally recorded on the video disc 12 after being subjected to frequency modulation (FM).

Since the detection signal information is an extremely small signal, it is sufficiently amplified by the amplifier circuit 14.

This amplified output is processed by a signal processing circuit 15 including an FM detection circuit, etc.
The signals are converted into video and audio signals that can be played on television receivers, etc.

A synchronization signal (horizontal or vertical synchronization signal) is separated from the video output of the signal processing circuit 15 by a synchronization separation circuit 16 .

The phase comparison circuit 18 compares the phases of the synchronization signal thus obtained and the reference signal (set to a horizontal frequency, for example) from the reference signal generation circuit 17.

This phase comparison output is smoothed by an integrating circuit 19 and then supplied to a motor drive circuit 20.

Thereby, the motor drive circuit 20 controls the rotation speed of the motor 21.

By controlling the motor 21, the rotation of the disk 12 is controlled so that the synchronization signal and the reference signal are in phase, and the linear velocity is kept constant.

On the other hand, the signal information detection section 13 is moved in the radial direction of the disk 12 by a carriage mechanism (not shown), and this movement control is also performed in accordance with a control signal from the motor 21.

For example, the center side of the disk 12 is transferred at a fast transfer speed, and the outer circumferential side of the disk 12 is transferred at a slow transfer speed.

To start playing the disc 12, the motor control circuit 23 is operated by a signal from the input key 22, and the output of the motor control circuit 23 causes the motor 21 to rotate the turntable 11. This is done by driving a carriage mechanism.

On the other hand, when the signal information detection section 13 reaches the recording end point of the signal information, conventionally a switch device 24 is provided at a position corresponding to this recording end point, and this switch device 24 is activated by the carriage mechanism of the signal information detection section 13, for example. By turning on (or off), the motor control circuit 24 is controlled to return the signal information detection section 13 to, for example, the reproduction start point.

However, with this method of detecting the position of the signal information detection unit 13 using the switch device 24, the accuracy of the detection position is determined by mechanical factors such as the mounting position of the switch device 24. There were problems such as easy to vary.

This idea was made in order to deal with the above situation, and by making it possible to detect the position of the signal information detection section on the recording disk by electrical means, the accurate position of the recording disk can be reliably detected. The purpose is to provide a playback device.

Hereinafter, one embodiment of this invention will be described in detail with reference to the drawings.

In FIG. 2, 31 is a turntable.

32 is a video disc placed on the turntable 31 and driven to rotate.

33 is a signal information detection section that detects signal information recorded on the video disc 32.

This signal information detection section 33 is attached to, for example, an arm device (not shown), and this arm device is controlled to move in the radial direction of the disk 32 by a carriage device (not shown), so that the playback needle traces the track and detects the signal information. It is something to detect.

The carriage device is, for example, a device that transmits the rotational motion of a motor 41 (described later) to the arm device via a deceleration mechanism, a timing belt, etc., and controls the arm device to move in the radial direction of the disk 32.

The output of this signal information detection section is an FM-modulated video signal or audio signal, which is amplified to a sufficient amplitude for FM detection by the subsequent amplifier circuit 34.

This amplified output is transmitted to a signal processing circuit 35 including an FM detection circuit, etc.
The signals are then converted into video and audio signals that can be played on television receivers, etc.

The video output of this signal processing circuit 35 is supplied to a synchronization separation circuit 36, where a synchronization signal (horizontal or vertical synchronization signal) is separated.

This separated synchronization signal is supplied to a phase comparator circuit 37, where the phase is compared with a reference signal from a first reference signal generation circuit 38, and the rotational state of the disk 32 is detected.

This comparison output is supplied to a smoothing integration circuit 39 and converted into a low frequency signal.

This smoothed output is supplied to the motor drive circuit 40.

The motor drive circuit 40 controls the rotation speed of the motor 41 according to the level of the supplied smoothed output.

As a result, the turntable 31 is rotationally driven so that the synchronization signal of the reproduced video signal has a predetermined period, so that normal reproduction is performed even on the disk 32 of the constant linear velocity force type.

Since the signal information detection section 33 has a transition speed controlled in accordance with the control signal from the motor drive circuit 40, signal reproduction can be performed satisfactorily.

By the way, when reproducing a disk 32 of a constant linear velocity force type, the number of revolutions of the disk 32 is small on the outer peripheral edge side of the disk 32, and the transition speed of the signal information detection section 33 is also slow.

On the contrary, on the center side of the disk 32, the number of rotations of the disk 32 is high, and the transition speed of the signal information detection section 33 is also fast.

The output of the integrating circuit 39 is low when the outer edge of the disc 32 is being reproduced, and is high when the center of the disc 32 is being reproduced.

Therefore, by detecting the output of the integrating circuit 39, it is possible to detect where on the disk 32 the signal information detecting section 33 is located.

This point will be explained below.

Reference numeral 43 denotes a reference voltage generation circuit as a second reference signal generation circuit, which derives a voltage equal to the output voltage of the integration circuit 39 when, for example, the signal information detection section 33 is located at the recording end point of the signal information on the disk 32. do.

The output of the reference voltage generation circuit 43 is compared with the output of the integration circuit 39 by a voltage comparison circuit 42.

The voltage comparison circuit 42 derives a detection signal when, for example, the output voltage of the reference voltage generation circuit 43 and the output voltage of the integration circuit 39 match.

Therefore, by driving the motor control circuit 44 using this detection signal, the signal information detection section 33 can be moved to, for example, a reproduction start point.

Further, by driving the display circuit 45, it is possible to inform the user that the signal information detection section 33 has reached the recording end point of the signal information.

For example, if a voltage-switchable reference voltage generating circuit 43 is used, the user can set the detection position arbitrarily, and if a plurality of different voltages can be set, the user can set the detection position at will. Signal information detection unit 33 in
It is possible to sequentially detect the positions of

In addition, 46 in the figure is an input key to temporarily stop playback (stop).
), fast forward, fast reverse, etc., and switches the driving state of the motor control circuit 44 for the motor 41 by deriving a signal corresponding to each operation.

In the device configured and operated as described above, the phase comparison circuit 37, reference signal generation circuit 38, and integration circuit 39 constitute error signal detection means, and the voltage comparison circuit 42 and reference voltage generation circuit 43 constitute position detection means. be done.

In addition, a motor drive circuit 40, a motor control circuit 4
4 constitutes rotation control means for the motor 41.

This embodiment described in detail above has the following effects.

Since the configuration electrically detects the position of the signal information detection section 33, the accurate position of the signal information detection section 33 can be detected reliably.

In addition, by appropriately changing the output voltage of the reference voltage generation circuit 43, the detection position can be accurately set at a desired location on the disk 32, and if a voltage switchable one is used as the reference voltage generation circuit 43, the detection position can be set accurately. The setting position can be easily and freely selected.

In this regard, conventional devices require the provision of multiple switch devices in order to be able to arbitrarily select the detection position, and also require control means to operate only the desired switch device. The disadvantage is that the configuration is complicated.

In addition, by being able to reliably detect the set position as described above, the signal information detection unit 3
If the control operation of the motor control circuit 44 for the motor 41 is set to move the motor 41 to the recording start point when the number 3 is reached, reproduction can be reliably performed without causing problems such as unreproduced parts.

Note that this invention is not limited to the previous embodiment.

For example, in the previous embodiment, the output of the phase comparison circuit 37 was integrated by the integration circuit 39 and used as the position detection signal, but the output of the phase comparison circuit 37 may also be used.

Various other modifications can be made without departing from the gist of the invention.

As described above, according to this invention, it is possible to provide a recording disc reproducing apparatus that can reliably detect the accurate position of the signal detection section on the recording disc.

[Brief explanation of drawings]

FIG. 1 shows the countries that constitute a block for explaining a conventional recording disk reproducing apparatus, and FIG. 2 shows the countries that constitute a block showing an embodiment of the recording disk reproducing apparatus according to this invention. 32...Video disk, 33...Signal information detection unit, 36...Synchronization separation circuit, 37...
...Phase comparison circuit, 38...Reference signal generation circuit, 39...Integrator circuit, 40...
Motor drive circuit, 41...Motor, 42...
... Voltage comparison circuit, 43 ... Reference voltage generation circuit, 44 ... Motor control circuit.

Claims (1)

[Scope of utility model registration request] Signal information detection in which video and audio signal information is recorded according to a linear velocity constant force formula, and the signal information is detected by controlling the movement along the radial direction on a recording disk that is placed on a turntable and driven to rotate. , a sync separation circuit that separates a sync signal from a video signal obtained by reproducing the output of the signal information detection section, and a phase comparison between the output of the sync separation circuit and the output of the first reference signal generation circuit. means for detecting an error signal according to the phase difference, and comparing the output of the error signal detection means and the output of a second reference signal generation circuit to detect the position of the signal information detection section on the recording disk. and means for controlling the rotation of the motor for driving the turntable and the signal information detecting section in accordance with the output of the error signal detecting means and the output of the position detecting means.