JP2534725B2 - Disk rotation control device - Google Patents

Description

The present invention relates to a disc rotation control device, and more particularly to a disc rotation control device for reproducing a signal recorded on an optical disc or a magnetic disc by controlling the rotation of the disc. The present invention relates to a disk rotation control device that performs feedback (silent loop) control.

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

[Problems to be Solved by the Invention] Therefore, in the conventional apparatus as described above, a delay time is generated from the detection of information to the rotation control of the motor, and the jitter component of the signal recorded on the disk is delayed by this delay. When the time is smaller than the time, there is a drawback that the rotation of the motor cannot be controlled.

On the other hand, in the case where only the information obtained from the signal reproduced one rotation or more before the rotation control position of the disk is used as the reference signal used for the rotation control of the motor for controlling the rotation of the disk, When the head cannot trace the track under the same condition in the previous rotation and the current rotation due to an external factor, the correlation of the jitter component is weakened, resulting in a large error in the prediction control.

Therefore, it is an object of the present invention to eliminate the above-mentioned drawbacks and provide a disk rotation control device that can obtain a reproduction signal with less jitter.

[Means for Solving the Problems] In order to achieve such an object, according to the present invention, it is possible to continuously reproduce the recording signal on the same track on the disc on which the signal is recorded by the same head. In the disc rotation control device of the signal reproducing device, a driving unit that rotationally drives the disc, and a measuring unit that measures the generation interval of the synchronization signal included in the reproduction signal from the head at the cycle of the synchronization signal, First correction means for correcting the rotation control signal for controlling the rotation of the disk on the basis of the comparison between the measurement value measured by the measurement means and a predetermined specified value for each measurement operation of the measurement means; The first
The output of the correction means said (v ₃₎ disk delaying time obtained by subtracting the delay time of the control system from the time that one revolution first delay means (12), the output of the first correction means (v ₃ ) And a rotation control value (v ₂ ) of the disk at a predetermined time, which is delayed by a predetermined time shorter than the first delay means, the first correction at the predetermined time during one rotation of the disk. Means output (v ₇ )
And a second delay means (13) for obtaining the rotation control value (v ₆ ) of the disk, and the output of the first delay means based on the outputs (v ₆ , v ₇ ) of the second delay means. A calculation means (14) for correcting (v ₄ ) and calculating a control value (v ₅ ) to be supplied to the driving means is provided.

[Operation] The present invention includes a sync signal interval (H interval) which is included in a reproduced signal of a signal analog-recorded or digitally recorded on a disc and is arranged to be arranged at equal intervals.
Paying attention to the fact that the same head can trace the same track continuously for two or more revolutions, and the jitter component contained in the same reproduction signal on the same track is when the same head traces a disk rotating under the same condition. , There is a correlation between the traces of the previous rotation and the current rotation,
Since the difference between the rotation conditions of the previous rotation and the current rotation can be corrected by the information in the current rotation, the rotation of the disk is predicted and controlled so that the H interval at the time of reproduction becomes equal to the specified value. It is possible to eliminate the conventional drawbacks and obtain a reproduced signal with less jitter.

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

FIG. 1 shows a circuit configuration of one embodiment of the present invention. In the figure, 1 is a disk rotation motor, 2 is a disk including a recording medium for recording a recording signal by rotation control,
Reference numeral 3 is a head for reproducing the recording signal of the disk 2, 4 is an amplifier for amplifying the reproduction signal from the head 3, and 5 is an H separation circuit for extracting a horizontal synchronizing signal (H) from the amplified reproduction signal. It is stipulated that Hs are arranged at equal intervals included in the reproduced signal.

6 is a fixed frequency oscillator (CLK), 7 is a counter that counts the fixed frequency of the fixed frequency oscillator 6 and outputs the count value n of the H period, 8 is a latch circuit that latches the count value n of the counter 7, and 9 is A memory that stores a specified value (fixed value) N of the oscillation output count value of the oscillator 6 corresponding to an ideal H period, 10 is a latch circuit that latches a control signal v ₁ described later in synchronization with the H signal, 11 Is n, N, v ₂
Arithmetic circuit for calculating a calculation value v ₃ from 12 the delay circuit to produce a delayed signal v ₄ from the arithmetic value v _3, 13 are representative values of v ₁ in the H period v ₂ and correcting the delayed signal v from the calculated value v _{3 A} delay circuit that produces ₆ and v ₇ , and 14 is an arithmetic circuit that calculates the correction arithmetic value v ₅ from the delay signals v ₄ , v ₆ , and v ₇ . Reference numeral 15 is a low-pass filter that removes high-frequency components from the correction calculation value v ₅ to generate the control signal v ₁ , and 16 is a driver that drives the motor 1 in accordance with the control signal v ₁ .

 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, 3600
After rotation at (rpm), the signal recorded on the disk 2 (for example, a still image signal of analog recording) is reproduced by the head 3, and the reproduced signal is amplified by the amplifier 4. The amplified reproduction signal is separated in the H separation circuit 5 into H (synchronization signal) used in the internal circuit and the reproduction signal output to the external circuit.

On the other hand, the counter 7 is counted up by the oscillation output f of the oscillator 6, and every time H is input from the H separation circuit 5,
After holding the count value n at that time in the latch circuit 8,
Will be reset. Further, the rotation control signal of the motor 1 in the m-th (m is an arbitrary integer indicating the number of H periods) H-period
The representative value v ₂ of v ₁ is held by the latch circuit 10 and
Count value n in the m-th H period held in
, And m (the order of the H period) is synchronized by the latch circuit 10, and v ₂ and n thereof are input to the arithmetic circuit 11. At the same time, the specified value N corresponding to the specified H period is output from the memory 9 to the arithmetic circuit 11.

In the arithmetic circuit 11, the above-mentioned count value n and the representative value
Using v ₂ and the specified value N, a calculated value v ₃ for controlling the rotation speed of the motor 1 when the signal is reproduced from the head 3 after the disk 2 has rotated once is calculated as described later.

That is, in the m-th H period of the Tth rotation of the disk 2 (T is an arbitrary integer indicating the number of rotations), both when the count value n is larger than the specified value N, that is, when the rotation of the disk is fast. The difference Δn between n and N is given by the following equation (1). In this case, the representative value v ₂ when the mth H period of the Tth rotation is traced is traced, and the mth H period of the T + 1th rotation is traced. The calculated value v ₃ previously expressed by the following equation (2) is used.

Similarly, when the count value n is smaller than the specified value N, that is, when the rotation of the disk is slow, the calculated value v ₃ shown by the following equations (3) and (4) is used.

The rotation control signal in the m-th H period of the (T + 1) th rotation such that the H interval becomes the same as the specified value N is obtained from the above equations (1) to (4) as in the following equation (5). Therefore, in the arithmetic circuit 11, the arithmetic value v _{3 represented} by the following equation (5)
Then, in the next delay circuit 12, the calculated value v ₃ is delayed by a time obtained by subtracting the delay time of the electric system and the mechanical system from the time required for the disk 2 to make one rotation based on the calculated value v ₃ . The delay signal v ₄ is created and output to the arithmetic circuit 14.

Further, the above-mentioned representative value v ₂ and calculated value v ₃
In 13, the correction delay signals v ₆ and v ₇ are delayed by a delay time corresponding to the H period of a (a is a constant, and is the number of H periods up to the H period slightly before the mth H period). Is generated and output to the arithmetic circuit 14. The arithmetic circuit 14 calculates the delay signal v ₄ by the correction delay signals v ₆ and v ₇ and the multiplication correction coefficient b.
Is calculated as described later to calculate a correction calculation value v ₅ .

That is, in the m−a th H period of the disk 2, the delay signal v ₆ having the representative value v ₂ is the delay signal v ₄ obtained from the information in the m th −m th H period of the Tth rotation and the T + 1th rotation. _Is a predictive control value added with the addition correction variable x _ma obtained from the information in the m−2a-th H period of
Since the delay signal v ₇ of v ₃ is a control value obtained from the control result in the m−a th H period of the T + 1th rotation, the difference between the correction delay signals v ₇ and v ₆ becomes a prediction control error. Here, since the addition correction variable x _ma in the m−a th H period of the T + 1 th rotation is added to v ₆ , the correction value x _m in the m th H period of the T + 1 th rotation is calculated by the following equation (6) ) Is required.

x _m = x _ma + (v ₇ −v ₆ ) b (6) Then, the control signal v ₄ of the mth H period of the T + 1 rotation
Is the information in the m-a th H period of the T rotation and T +
According to the result of the above formula (6) obtained by using the information in the m-a th H period of the first rotation, when the correction is performed as the following formula (7), the rotation conditions of the Tth rotation and the T + 1th rotation are The difference is corrected and the correction calculation value v ₅ is calculated.

v ₅ = v ₄ + x _m (7) The correction calculation value v ₅ calculated by the calculation circuit 14 in this way is
Further, high-frequency components are removed by the low-pass filter 15 and sent as a control signal v ₁ to the motor driver 16 and the latch 10.

It is possible to obtain a reproduction signal with less jitter by circulating and executing the reproduction feedback control described above.

Next, as a modified example of the above-described embodiment of the present invention, another calculation method when the calculation value v ₃ is calculated by the calculation circuit 11 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 (8) only when the above equation (5) Calculated value by v ₃
And the other uses the representative value v ₂ as it is as the calculated value v ₃ .

| Δn | -l> 0 (8) As the second calculation method, the difference Δn in the above equations (1) and (3) and the upper limit h of | Δn | ) Is satisfied, the calculated value v ₃
And the others use the constant c ₁ as the calculated value v ₃ .

| Δn | −h <0 (9) As a third calculation method, a constant c ₂ is set in advance, and the above equation (8) and the above equation (9) are applied to the above equation (1) at the same time. When satisfying the following equation (10), and when satisfying the above equation (8), the above equation (9) and the above equation (3) at the same time, the following equation (11) is used.
Is used to calculate the calculated value v ₃ .

v ₃ = v as _{2 + c 2 ... (10)} v 3 = v 2 -c 2 ... (11) further fourth computing method is intended to combine the third calculation method from the first described above.

The first calculation method described above can prevent malfunctions due to noise components, and the second calculation method can prevent a sudden change in control due to a defect in the H signal or noise. In addition, there is an advantage that the arithmetic circuit can be simplified by using the third arithmetic method.

[Effects of the Invention] As described above, according to the present invention, a synchronization signal which is included in a reproduction signal of a signal analog-recorded or digitally recorded on a disc and is arranged to be arranged at equal intervals is defined. Paying attention to the interval (H interval), the same head can trace the same track continuously for two or more revolutions, and the jitter component contained in the same reproduction signal on the same track is the same for disks rotating under the same conditions. When the head traces, by utilizing the fact that there is a correlation between the traces of the previous rotation and the current rotation, and that the difference between the rotation conditions of the previous rotation and the current rotation can be corrected by the information in the current rotation, Since the rotation of the disk is predicted and controlled so that the interval becomes equal to the specified value, the conventional defects can be eliminated and a reproduced signal with less jitter can be obtained. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an embodiment of the present invention. 1 ... Motor, 2 ... Disk, 3 ... Head, 4 ... Amplifier, 5 ... H separation circuit, 6 ... Fixed frequency oscillator, 7 ... Counter, 8 ... Latch, 9 ... Memory, 10 …… Latch, 11 …… Operation circuit, 12 …… Delay circuit, 13 …… Delay circuit, 14 …… Operation circuit, 15 …… Low-pass filter, 16 …… Driver.

Claims (1)

(57) [Claims] 1. A disc rotation control device of a signal reproducing device capable of continuously reproducing a recording signal on the same track on a disc on which a signal is recorded by the same head. B. Drive means for performing the measurement, c. Measurement means for measuring the generation interval of the synchronization signal included in the reproduction signal from the head in the cycle of the synchronization signal, and d. For each measurement operation of the measurement means. First correction means for correcting the rotation control signal for controlling the rotation of the disk on the basis of the comparison between the measurement value measured by the means and a predetermined specified value; and e. The output of the first correction means ( v ₃ ) said disk is 1
A first delay means (12) for delaying a time obtained by subtracting a delay time of a control system from a rotating time, f. An output (v ₃ ) of the first correcting means, and a rotation control of the disk at a predetermined time. By delaying the value (v ₂ ) by a predetermined time shorter than the first delay means, the output (v ₇ ) of the first correction means and the rotation of the disk at the predetermined time during one rotation of the disk. A second delay means (13) for obtaining a control value (v ₆ ), and g. An output (v ₄ of the first delay means based on the outputs (v ₆ , v ₇ ) of the second delay means. ) To calculate the control value (v ₅ ) to be supplied to the drive means (14)
A disk rotation control device comprising: