JPS6348657A - Controller for disk drive motor in video disk player - Google Patents

Abstract

PURPOSE:To contrive to reduce the cost by detecting a frequency of a reproduced FM signal so as to detect whether or not a spindle motor reaches the specified number of revolutions thereby eliminating the need for a potentiometer and a frequency generator. CONSTITUTION:If number of revolutions of the spindle motor 1 is deviated largely, a phase difference detector 7 cannot output information of speed deviation and the control of number of revolutions of the spindle motor 1 is disabled. In such a state above, since the output of a frequency detector 8 is at the outside of the range between voltage conversion values VL and VH, the level of an output line 11 of a level detector 9 goes to an L level and a switch 10 selects a line 12. In this state, a speed control loop taking the frequency of the reproduced FM signal at the normal state as an object of the number of revolutions of the spindle motor 1 is formed and the spindle motor 1 is controlled to reach the specified number of revolutions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to rotational control of a disc drive motor of a video disc player, and in particular to the rotation control of a disc drive motor of a video disc player.
instant 1inear velocity:
The present invention relates to a drive motor control device for such a disc, which can be suitably used when playing a disc (constant linear velocity).

[Conventional technology]

Such a conventional disc drive motor control O1l' device is as follows:
As described in Japanese Patent Laid-Open No. 52-40308, the rotational speed π is set according to the radial position of the disk where the pickup is located, such as constant linear velocity (CLV) disk, that is, 1800 rpm at the inner periphery of the disk and 600 rpm at the outer periphery. When playing a disc that adopts the method of changing the speed, a potentiometer for indicating the playback position (pickup position) in the radial direction of the disc 4 is linked with a spindle motor as a disc drive motor to control the rotational speed of the motor. A frequency sputtering device was used to control the change according to the playback position and to detect the entire rotational speed of the motor.

In other words, in a CLV disc, in order to keep the recording density constant, the rotation speed changes between the inner and outer circumferences of the disc being played.For example, if it is a 30 crrL disc, as mentioned earlier, , 180 Or at the innermost circumference
pm, and at the outermost periphery, it is necessary to set it to about 1/3 of that, 60 Orpm. This means that the output frequency of the frequency generator, that is, the rotation speed of the spindle motor, is controlled so that it becomes the normal rotation speed, with the value of the potentiometer linked to the pickup as the target for the total rotation speed.

However, since it is not possible to maintain the motor rotation speed at an accurate rotation speed using only such a control loop for rotation speed control, it is necessary to use the synchronization signal extracted from the playback video signal and the reference synchronization signal generator. The spindle motor is controlled to maintain an accurate rotational speed by comparing the phase with a reference synchronization signal and superimposing the phase mirror cover output on the control loop described above.

However, such a conventional configuration requires an expensive potentiometer and a frequency generator, and requires strict precision in mounting the potentiometer, making it very expensive in terms of cost.

[Problem that the invention seeks to solve]

The above conventional technology detects the playback position (pickup position) t in the half-i direction of the disk based on the value of the potentiometer during playback of a CLV disk, and fully variable control of the rotational speed of the spindle motor accordingly. During playback, the number of revolutions will not be the same for the same playback position, and an error will inevitably occur between them, and in order to minimize that error, install a potentiometer! The problem is that very strict accuracy is required. Furthermore, since a frequency generator and a potentiometer are required, there is a problem in that the cost becomes high.

An object of the present invention is to configure a speed control loop even for a disc, such as a CLV disc, where the number of revolutions must be variably controlled according to the playback position in the disc radial direction, without requiring a potentiometer or a frequency generator. An object of the present invention is to provide a control device a for a disk drive motor (spindle motor) that can realize a normal rotational speed of 1vIaII at low cost and low cost.

[Means for solving problems]

The above purpose is to detect the frequency of the reproduced FM signal,
This is achieved by detecting whether or not the disk deviates from the normal rotational speed (for a CLV disk, the rotational speed changes depending on the Tj% position). In other words,
This means that CAV (constantangular
The frequency of the FM signal obtained by playing a velocity disc or a CL disc is always constant as long as the disc's rotational speed is in line with the regular rotational speed. There is.

Since the disc playback signal is an FM signal, its frequency is modulated in a predetermined format, and the frequency varies within a predetermined deviation range. Therefore, when the frequency of the reproduced FM signal deviates outside the deviation range, it can be determined that the disc rotational speed has deviated from the normal rotational speed.

Therefore, in the present invention, the error can be reduced to zero using a phase error output obtained by comparing the phases of the horizontal synchronization signal extracted from the reproduced video signal and the horizontal synchronization signal obtained from the reference synchronization signal generator. The disk drive motor, that is, the spindle motor, is controlled so that the Since this control loop is a phase control loop, once the rotational speed of the motor deviates from the normal rotational speed, it becomes impossible to bring it back to the normal rotational speed. Therefore, in such a case, the frequency of the reproduced FM signal 'r! i is detected and the control is switched to a control loop that controls the rotational speed of the motor so that the frequency becomes a constant predetermined frequency, that is, a speed control loop that focuses on the frequency of the reproduced FM signal.

For this purpose, a predetermined lower limit or upper limit of deviation is set for the frequency of the reproduced FM signal, and when the frequency of the reproduced FM signal is within the range of the above set value, the motor rotation speed will be increased. ! Since the rotation speed is in line with the normal rotation speed, it is only necessary to enable the above-mentioned phase control loop, and if the frequency of the reproduced FM signal deviates from the set value range, the motor rotation speed will be adjusted to the normal rotation speed). Since this is the case, the configuration is such that the speed control loop is switched to the above-mentioned speed control loop focusing on the frequency of the reproduced FM signal. As a result, when the motor rotation speed reaches the normal rotation speed, the speed control loop focusing on the frequency of the reproduced FM signal is switched to the above-mentioned phase control loop, and the motor rotation speed is drawn into the phase control loop.

[Effect]

As already explained, the frequency of the reproduced FM signal can be said to indicate whether or not the rotational speed of the spindle motor is in accordance with the normal rotational speed.

Therefore, if the frequency of the reproduced FM signal is detected and it is detected that the frequency is within a certain predetermined range,
It can be determined that the spindle motor is rotating accurately at the normal rotation speed. If the frequency of the reproduced FM signal deviates from the predetermined range, the spindle motor may be controlled so that the frequency falls within the predetermined range. Therefore, by detecting the frequency of the reproduced FM signal, it is possible to detect whether the spindle motor is following the normal rotation speed, thereby eliminating the need for a potentiometer or a frequency generator, thereby reducing costs. Can be done.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained with reference to FIG.

In Fig. 1, 1 is a spindle motor, 2 is a disk, and 3 is a pickup for reproducing the entire FM m number from the rotating disk and comparing the readings.
The M signal is input to an FM demodulator 4 and a frequency detector 8.

The video signal (video signal) which is the demodulated output of the FM demodulator 4 is input to a horizontal synchronizing signal separation circuit 5, where the horizontal synchronizing signal is separated. The reproduced horizontal synchronizing signal separated by the circuit 5 is input to one input terminal of the phase difference detector 7, and the reference horizontal synchronizing signal output from the reference horizontal synchronizing signal generator 6 is input to the phase difference detector 7. is input to the other input terminal,
An output corresponding to the phase difference between the two is output to line 13 and guided to one input side of switch 10.

On the other hand, the above-mentioned frequency detector 8 is usually composed of a frequency-voltage converter, and the output voltage of the frequency detector 8, which is different from the frequency of the input reproduced FM signal, and the reference voltage (reproduced When the frequency of the FM signal is within a predetermined range, the error voltage obtained by comparing the corresponding predetermined voltage) 20 with the comparator 21 is outputted from the comparator 21 and applied to the switch 10 via the line 12. guided to the other input side.

At the same time, the output of the frequency detector 8 is transmitted to the level detector 9.
is input to. The level detector 9 is for detecting whether the output level from the frequency detector 8 manually input is within a predetermined level range. In other words, the frequency of the reproduced FM signal is within a predetermined level range. This is to detect whether the frequency is within the frequency range of . In other words, the voltage value m at a frequency slightly lower than the lower limit frequency when the reproduced FM signal is normal is set as vL, and the voltage equivalent value m at a frequency slightly higher than the upper limit frequency is set as vH. However, if the output signal from the incoming frequency detector 8 is within the range from vL to vH, its output line 11 outputs an H level, and if it is lower than vL or higher than VH, the output line 11 outputs an H level. 11 outputs L level.

Furthermore, when the line 11 is at the L level, the switch 10 selects the line 12, and when the line 11 is at the H level, the switch 10 selects the line 13.

In this configuration, when the spindle motor 1 rotates at the normal rotation speed, the output of the frequency detector 8 is between vL and VHO and is normal, so the line 1
1 becomes H level, and the signal on line 13 is selected by switch 10 and connected to spindle motor 1 as its speed control signal.

That is, the reproduced horizontal synchronizing signal and the reference horizontal synchronizing signal are phase-compared by the phase difference detector 7, and the rotation speed of the spindle motor 1 is fully controlled based on the phase difference output so that the phase difference becomes zero.

On the other hand, if the rotation speed of the spindle motor 1 deviates significantly,
The output of the phase difference detector 7 cannot provide a seasonal report of the misalignment, and it becomes impossible to control the rotational speed of the spindle motor 1.

In such a situation, the output of the frequency detector 8 is
Since it is outside the range of vL and vH, the level detector 9
The output line 11 of is at L level, and the switch 10 is at line 12.
Select. In this state, a speed control loop is configured in which the normal frequency (reference voltage 20) of the reproduced FM signal is used as the target value for the rotation speed of the spindle motor 1, and the spindle motor 1 is controlled to have the normal rotation speed. Ru. When the rotation speed of the spindle motor 1 is controlled to such an extent that the output of the frequency detector 8 falls within the range of vL and vH again, the switch 10 selects the line 13 again and switches to the phase control loop. , the rotational speed of the spindle motor 1 can be precisely controlled.

As explained above, by applying speed control that focuses on the frequency of the reproduced FM (M number), the speed of the spindle motor 1 can be applied not only to CAV discs but also to CLV discs, regardless of the radial position of the reproduction pickup. The rotation speed can be easily controlled.

When the number of times a is normal, the reproduction horizontal synchronization signal
A phase 1 fishing control loop is formed by comparing the phase of the reference horizontal synchronization signal, and the readiness information detected from the frequency of the reproduced FM signal is not included in the control Q'J loop. The frequency fluctuation does not adversely affect rotational speed control.

The frequency information of the reproduced FM signal is not effective when the motor rotation speed deviates significantly, and in this case, the motor is designed to quickly return the rotation speed to near the normal rotation speed. . Another advantage of configuring such a speed control loop is that it can be started no matter where the reproducing pickup on the disk is located along the radial direction of the disk.

Normally, in order to speed up the startup of the spindle motor, full power is applied to the spindle motor at K and startup R.
In many cases, the system detects that the rotational speed has risen to a certain degree and then switches to a speed control loop, but in this case, it is recommended to use a high-frequency generator to detect the rising rotational speed at startup. Then, in the case of a CLV disk, it is necessary to return the pickup position j+'l- to the innermost circumferential position and set the disk rotational speed to the highest level before starting the disk.

However, in this embodiment, since the rotational speed is detected by detecting all frequencies of the reproduced FM signal, as long as the rotational speed is at the normal speed at any position in the radial direction of the disk, the reproduced F artificial signal is detected. Since the frequency should be constant, it can be activated from any position in the radial direction of the disk.

In the embodiment shown in FIG. 1, an integrator or hysteresis circuit may be added in the middle of the heel 11 to stabilize the control operation.

Next, the reason why a reproduced FM signal is intentionally used in the present invention will be described. In order to detect the rotation speed of the spindle motor, it is also possible to adopt a method that uses the horizontal synchronization signal, vertical synchronization signal, burst signal, etc. in the video signal obtained from the FM demodulator. It is.

However, due to the demodulated Si characteristics (commonly called 8-character characteristics) of the FM demodulator 4, the frequency range of the FM signal that can be demodulated is limited. There is a problem that the signal is not demodulated.

In this respect, it is advantageous for the reproduced FM signal to be detected even if the deviation in rotational speed is wide if the frequency characteristics of the pickup 3 are wide enough.

In an optical video disk player, since the frequency of the FM signal is high, about 8 MHz, a frequency divider having an appropriate frequency division ratio may be added in front of the frequency detector 8.

Next, another embodiment will be explained with reference to FIG. In FIG. 2, the same reference numerals as in FIG. 1 indicate the same functions. In this embodiment, the output of the comparator 21 is input to the dead band circuit 14, the output of which is input to one input terminal of the adder 15, and the other input terminal of the adder 15 has a phase difference The output of the detector 7 is input. Then, the output of the adder 15 is sent to the spindle motor 1 at a speed of 411
It is folded as ＠ > and controls the rotational speed.

The dead band circuit 14 is configured such that the output of the frequency detector 8 is a reproduced FM
If the change is within the deviation frequency range of the signal and is recognized as normal, the output of the comparator 21 is inactive, that is, it is not output to the line 16 and is in an open state. When the input to the dead band circuit 14 becomes large enough to exceed the dead band, the input to the dead band circuit 14 is output as is on the line 16.

It is desirable that the dead band of the dead band circuit 14 is set to work for range 2B exceeding the normal deviation of the reproduced FM signal.

Also in the embodiment shown in Figure 2, if the rotational speed of the spindle motor l is in the normal range, the gauze 16 is opened, and the phase control loop in which the spindle motor 1 impulse jJ is controlled by the output of the phase difference detector 7 is established. is configured, and if the rotation speed deviates significantly,
Speed difference (frequency difference) information is output to the line 16, and the spindle motor 1 is controlled to the normal rotation speed, and when the normal rotation speed is reached, the control loop returns to the phase-1 control loop as described above. , the rotation speed is accurately controlled.

Also on the implementation side of Figure 2, a frequency divider may be forced to pass before the frequency detector 8.

Further, the dead band circuit 14 does not necessarily need to be provided.

In other words, if the output of the frequency detector 8 is within the normal range,
The output of the comparator 21 is also small, and even if this is added to the adder 15, the output of the phase difference detector 7 acts more dominantly.
This is because when the output of the frequency detector 8 is significantly distorted, the output of the comparator 21 also becomes large, and when this is added to the adder 15, it acts more dominantly than the output of the phase difference detector 7.

As explained above, according to the present invention, it is possible to self-start from any position in the radial direction regardless of the type of disk, and it is inexpensive and stable as it eliminates the need for expensive potentiometers and frequency generators. A control circuit for a spindle motor can be obtained.

〔Effect of the invention〕

According to the present invention, it is possible to eliminate the need for an expensive potentiometer and a frequency generator, and therefore it is possible to construct a spindle motor OE control circuit as a disc hib motor in a video disc player with an inexpensive configuration. , performance can also be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the invention, and FIG. 2 is a block diagram showing another embodiment of the invention. Explanation of symbols 1...Spindle motor, 2...Disc, 3...Pickup, 4...F
hiul adjustment tM, 5...Horizontal synchronization signal separation port, 6...Reference horizontal synchronization signal generator, 7...
... Phase difference detector, 8 ... Frequency detector, 9
...Rehe/'Nlf [, 10... Switch, 14... Dead band circuit, 15...
Adder, 20...Reference voltage, 21...
Comparator representative Benmeshi Akira Namiki Fusha 1 diagram

Claims (1)

[Claims] 1. A control device for a disc drive motor in a video disc player, comprising: an FM demodulator that receives a reproduced FM signal reproduced from a disc, demodulates a video signal, and outputs the demodulated video signal; a phase difference detector that compares the synchronization signal separated from the reference synchronization signal with a reference synchronization signal and detects the phase difference; a frequency detector that receives the reproduced FM signal and detects and outputs the frequency; a comparator that compares the frequency output with a reference frequency output and generates an error output; a frequency output level detector that receives the frequency output detected by the frequency detector and detects and outputs the output level; When the detection level by the level detector is at a normal level, the output of the phase difference detector is selected as the speed control signal for the disk drive motor, and when the detection level is not at the normal level, the output from the comparator is selected. 1. A control device for a disc drive motor in a video disc player, comprising: a selection circuit for selecting an error output of the disc drive motor as a speed control signal for the disc drive motor. 2. In the control device for a disk drive motor in a video disk player as set forth in claim 1, the frequency output level detector is configured such that the inputted frequency output corresponds to the upper limit frequency of the reproduced FM signal during normal operation. When the frequency is within the range between a certain upper limit level that represents the frequency and a certain lower limit level that also represents the lower limit frequency, it is determined that the level is at the normal level, and when it is outside the range, it is determined that the level is not at the normal level. 1. A control device for a disc drive motor in a video disc player, characterized in that: 3. In the control device for a disk drive motor in a video disk player according to claim 1, in place of the frequency output level detector and the selection circuit, an error output from the comparator and an error output from the phase difference detector are provided. 1. A control device for a disk drive motor in a video disk player, characterized in that an adder is provided which receives the outputs of the outputs of the outputs of the outputs of the disk drive motor, adds the sum of the outputs, and outputs the sum as a disk drive motor control signal. 4. A control device for a disk drive motor in a video disk player as set forth in claim 3, characterized in that the adder inputs the error output from the comparator via a dead band circuit. A control device for a disc drive motor in a video disc player.