JPH0828038B2 - Disk rotation control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc rotation control device, and more particularly to electronic still video reproduction for reproducing a still image signal recorded on a disc by rotation control of the disc. Disk rotation control device.

[Prior Art] Conventionally, in this type of device, information obtained from a signal reproduced within one rotation before the rotation position of the disk is used as a reference signal used for rotation control of a motor for controlling rotation of the disk. Was.

[Problems to be Solved by the Invention] Therefore, in the conventional apparatus, there is a delay time from the detection of the above information to the rotation control of the motor, and the jitter component of the signal recorded on the disc is less than this delay time. There is a drawback that the rotation of the motor cannot be controlled for a small case.

It is therefore an object of the present invention to eliminate the above-mentioned drawbacks and to provide a disc rotation control device for electronic still video reproduction in which a reproduction signal with less jitter can be obtained.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an image signal recorded on a track rotated by a motor by continuously tracing the same track on the disk. In the disk rotation control device for predicting and controlling the rotation speed of the motor on the basis of the horizontal synchronizing signal in the image signal, the T-th (T is an arbitrary integer of 1 or more) rotation trace of the disk Measuring means for measuring the interval of the horizontal synchronizing signal in the image signal, storage means for storing the measured value measured by the measuring means, and the measured value and a predetermined specified value stored in the storage means On the basis of the information on the difference and the rotation control value of the motor at the time of the Tth rotation of the disk, Control means for predicting the rotation control value of the motor so that the interval of the horizontal synchronizing signal becomes equal to the specified value.

[Operation] According to the present invention, in a disk device that reproduces a still image signal, the same head can trace the same track continuously for two or more revolutions, and the jitter component included in the same still image signal on the same track is When the reproducing head traces a disc rotating under the same conditions, T (T
Is an arbitrary integer greater than or equal to 1) There is a correlation between the trace at the 1st rotation and the trace at the T + 1st rotation, and as a reference signal used for the rotation control of the motor that controls the rotation of the disk, The measured value of the interval of the H signal separated from the still image signal reproduced at that time is used to predictably control the rotation of the disc so that the interval of the H signal at the time of reproduction becomes equal to the specified value. Because I did
It is possible to obtain a reproduced signal with less jitter by eliminating the conventional defects.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the circuit configuration of an embodiment of the present invention. In the figure, 1 is a disk rotation motor, 2 is a disk including a recording medium for recording an image signal by rotation control,
3 is a head for reproducing the image signal recorded on the disk 2, 4 is an amplifier (amplifier) for amplifying the reproduced signal input from the head 3, and 5 is a horizontal synchronization (hereinafter referred to as H) from the image signal amplified by the amplifier 4. H signal separation circuit for separating and extracting signals, 6 is a fixed frequency oscillator (CLK) that oscillates a fixed frequency f, and 7 is a count value of the fixed frequency f and outputs a count value n of the H period. A counter, 8 is a latch circuit for holding a count value n in the m-th (m is an arbitrary integer indicating the number of H periods) H period of the counter 7, and 9 is a theoretical prescribed value N corresponding to the prescribed H period. And other constants are stored in advance in the memory. Further, 10 is a rotation control signal of the motor 1 in the H period.
The latch circuit holds the representative value v ₂ of v ₁ and synchronizes with the count value n held by the latch circuit 8.

11 is a calculated value for predicting and controlling the rotation speed of the motor 1 when the signal is reproduced from the head 3 after the disk 2 makes one rotation, using the count value n, the specified value N, and the representative value v _2. An arithmetic circuit for calculating v ₃ , 12 is a delay circuit for delaying the arithmetic value v ₃ by subtracting the delay time of the electric system and the mechanical system from the time required for one rotation of the disk to generate a delay signal v ₄ ,
15 removes a high frequency component from the delayed signal v _4, a low-pass filter to produce a control signal v ₁ (LPF), the 16 control signal v ₁
Is a driver that drives the motor 1 in accordance with.

 Next, the operation of the above configuration will be described.

The disk 1 is driven by the motor 1 at a constant speed (for example, 3600r.
pm), the still image signal is reproduced from the disk 2 by the head 3, amplified by the amplifier 4, and then input to the H signal separation circuit 5. In the H signal separation circuit 5, the input still image signal is the H signal used in the internal circuit,
It is separated into a reproduced still image signal to be output to an external circuit.

On the other hand, the counter 7 is counted up by the oscillation output f of the oscillator 6, and when the m-th H signal separated by the H signal separation circuit 5 is input, after holding the count value n in the latch circuit 8, Will be reset.

Here, the count value of the latch circuit 8 in the m-th H period from the generation of the vertical synchronization (hereinafter abbreviated as V) signal reproduced at the Tth (T is an arbitrary integer of 1 or more) rotation of the disk. If n is larger than the specified value N stored in advance in the memory 9, the difference Δn between both N and n is
Is expressed by the following equation (1). In this case, based on the representative value v ₂ when the m-th H period in the T-th rotation trace of the disk 2 is traced, the representative value is changed to the m-th in the T + 1-th rotation trace. Before tracing the H period of, the calculation value v ₃ shown in the following equation (2) is set.

Δn = N−n <0 (1) The (2) v ₃ by equation, v is a value obtained by performing a change in the addition corrected according to the difference between v ₂ specified value ₂ N and the count value n.

Similarly, when the count value n of the latch circuit 8 is smaller than N of the memory 9, the difference Δn between the two N and n becomes the following expression (3), and the calculated value v ₃ shown by the following expression (4) And

Δn = N−n> 0 (3) Therefore, since the following equation (5) is generally obtained from the above equations (1) to (4), the arithmetic circuit 11 calculates the arithmetic value v ₃ represented by the following equation (5), and the delay circuit 12 Output to.

In the delay circuit 12, the delay signal v ₄ is generated by delaying the above-mentioned calculated value v ₃ by the time obtained by subtracting the delay time of the electrical system and the mechanical system from the time required for the disk 2 to make one rotation,
Send to low pass filter 15. With the low pass filter 15,
A control signal v ₁ is created by removing the high frequency component from the delay signal v ₄ and sent to the motor driver 16.

That is, a new predicted value v ₃ is obtained based on the information on the difference obtained by comparing the arbitrary H interval of the Tth rotation with the specified value, and this is delayed by one rotation, and the new predicted value v ₃ is delayed for the T + 1th rotation (next rotation). This is used as a rotation control prediction value, and a highly accurate prediction value can be obtained by using the correlation obtained by tracing the same track continuously, and the jitter component below the delay time of mechanical system and electrical system is also removed. can do.

By repeating the above operation, a reproduced signal with less jitter can be obtained.

Next, the operation value in the operation circuit 11 in the embodiment of the present invention described above.
Another calculation method for calculating v ₃ will be described.

First, as the first calculation method, the difference Δn in the above equations (1) and (3) and the lower limit l of | Δn | satisfy the following equation (6) only when the above equation (5) Calculated value by v ₃
And the others output the representative value v ₂ as it is as the calculated value v ₃ .

| Δn | -l> 0 (6) Further, as the second calculation method, the difference Δn in the above equations (1) and (3) and the upper limit value h of | Δn | Only when 7) is satisfied, the calculated value v _{3 according} to the above equation (5)
And outputs the constant C ₁ as the calculated value v ₃ .

| Δn | −h <0 (7) As a third calculation method, a constant C ₂ is set in advance, and the above equation (6), the above equation (7), and the above equation (1) are calculated. When satisfying at the same time, the following formula (8) is used, and when satisfying the above formula (6), the above formula (7) and the above formula (3) at the same time, the calculation value v ₃ is calculated using the following formula (9). To do.

_{v 3 = v 2 + C 2} ...... (8) v 3 = v 2 -C 2 ...... (9) Furthermore, the fourth from the third first described as a method of calculating the
It combines the calculation methods of.

When the above-mentioned first calculation method is used, malfunction due to noise components can be prevented, and when the second calculation method is used, the control abruptly changes when the H signal is missing or due to noise. It is possible to prevent this, and the third arithmetic method has an advantage that the arithmetic circuit can be simplified.

FIG. 2 shows a modification of the embodiment of the present invention shown in FIG. In FIG. 2, 13 is a representative value v ₂ of the control signal in the H period.
And a delay circuit for generating the correction delay signals v ₆ and v ₇ from the calculation value v ₃ , and 14 is a calculation circuit for calculating the correction calculation value v ₅ from the delay signals v ₄ , v ₆ , and v ₇ and other components. Since it is the same as the embodiment shown in FIG. 1, only the contents of addition and modification will be described below.

In the delay circuit 13, the typical value v ₂ output from the latch 10
Then, the calculation value v ₃ output from the calculation circuit 11 is delayed by a delay time corresponding to the H period of a constant number a to generate correction delay signals v ₆ and v ₇ and output to the calculation circuit 14. The arithmetic circuit 14 uses the correction delay signals v ₆ and v ₇ and the variable X to calculate the delay signal v ₄ output from the delay circuit using X ′ obtained by the following equation (10) by the following equation (11). is corrected by the arithmetic expression shown, it makes a correction calculation value v _5, and outputs the correction calculation value v ₅ to the low-pass filter 15.

_{X'= X + (v 7 -v} 6) ...... (10) v 5 = v 4 + X'...... (11) in the low-pass filter 15 from the correction calculation value v ₅ by removing high frequency components make the control signal v _1, Send to the motor driver 16.

In this example, based on the information of the mth H period of T rotations, the delay signal v ₄ for predictively controlling the mth H period of T + 1 rotations is the m−ath H period of T + 1 rotations. Correction is performed using the information of. Therefore, if the track cannot be traced under the same condition at the T-th rotation and the T + 1-th rotation of the disk due to an external factor, the conventional defect that the error of the prediction control becomes large because the correlation of the jitter component becomes weak is surely prevented. can do.

[Effects of the Invention] As described above, according to the present invention, in a disk device for reproducing a still image signal, the same head can trace the same track continuously for two or more revolutions, and the same still image on the same track. The jitter component contained in the signal is used when the reproducing head traces a disk rotating under the same condition, and there is a correlation between the Tth (T is an arbitrary integer of 1 or more) rotation and the T + 1th rotation. Then, as the reference signal used for the rotation control of the motor for controlling the rotation of the disk, the measured value of the interval of the H signal separated from the still image signal reproduced when the disk was rotated one rotation or more before is used. Thus, the rotation of the disk is predicted and controlled so that the interval of the H signal at the time of reproduction becomes equal to the specified value. It is possible to obtain an effect that it is possible to obtain a reproduction signal with less noise.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an embodiment of the present invention, and FIG. 2 is a block diagram showing a circuit configuration of another embodiment of the present invention. 1 ... motor, 2 ... disk, 3 ... head, 4 ...
Amplifier, 5 ... H signal separation circuit, 6 ... Fixed frequency oscillator, 7 ... Counter, 8 ... Latch circuit, 9 ... Memory, 10 ... Latch circuit, 11 ... Arithmetic circuit, 12 ... Delay circuit , 13 ... delay circuit, 14 ... arithmetic circuit, 15 ... low-pass filter, 16 ... driver.

Claims (1)

[Claims] 1. When reproducing an image signal recorded on the track by continuously tracing the same track on a disk rotated by a motor by a head, based on a horizontal synchronizing signal in the image signal. In a disk rotation control device for predictively controlling the rotation speed of the motor, a measuring means for measuring an interval between horizontal synchronization signals in the image signal by tracing the T-th (T is an arbitrary integer of 1 or more) rotation of the disk. Storage means for storing the measurement value measured by the measurement means, information on the difference between the measurement value stored in the storage means and a prescribed value, and a trace at the time of the T-th rotation of the disk. Based on the rotation control value of the motor, (T +
1) A disk rotation control device comprising: a control unit that predicts a rotation control value of a motor at the time of the trace of the rotation so that the interval of the horizontal synchronizing signal becomes equal to the specified value.