JPH02179287A - Rotary servo control system - Google Patents

Abstract

PURPOSE:To reduce power consumption by returning a servo state to a rough servo state when the servo is out of synchronization thereafter when a lead-in speed.phase servo is completed. CONSTITUTION:An optical disk 1 is rotated by a spindle motor 2 driven by a driver 3, which is controlled by a rotary servo system 4. Further, disk information is processed through an optical pickup 5, a waveform shaper 6, a synchronizing signal detector 7, a digital signal processor 8, and has a PLL circuit 9 and a reference signal generator 10. The servo system 4 has a rough servo circuit 11, a speed servo circuit 12, a phase servo circuit 13 and a selector 14. When a servo lead-in is completed up to a phase servo, it is returned to te rough servo when the servo is thereafter out of synchronization.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial application field This invention is applicable to, for example, a compact disc player (CD
This invention relates to a rotation servo control system used in players, etc.

(B) Conventional technology In the conventional spindle (CLV) servo system, as shown in Figure 3, servo retraction is performed from the rough servo which takes the servo in a relatively large chunk of data, and then the speed servo is retracted by detecting a synchronization signal. Then, the rotation speed is controlled to shift to phase servo, and operation continues with speed and phase servo.

On the other hand, if the rotational speed abnormally deviates during operation, the system goes from the speed/phase servo to the speed servo, and then returns to the rough servo.

(c) Problems to be Solved by the Invention In the above-mentioned conventional rotation servo control, there is a reversible transition between the rough servo and the speed servo, and between the speed servo and the speed/phase servo. When conversion is performed, the speed/phase mode and the speed mode are repeated, and switching the selector causes an increase in jitter and power consumption, which is a problem. Further, there is a problem in that the speed servo must always be passed in order to return from the speed/phase servo to the rough servo, which requires time.

This invention has been made in view of the above problems, and provides a rotation servo control system that eliminates switching after pulling in, reduces jitter and power consumption, and does not require time to shift to rough servo in the event of an abnormality. It is intended to.

(d) Means and Effects for Solving the Problems The rotary servo control system of the present invention is a rotary servo system in which the outputs of a rough servo circuit, a speed servo circuit, and a phase servo circuit are switched and outputted by a selector. , speed servo, and speed/phase servo, and when the servo comes off, the speed/phase servo returns to rough servo.

In this rotation servo control method, when the servo is retracted, it goes from the rough servo to the speed servo, and then enters the speed/phase servo, as in the conventional method. However, once the pull-in is completed, even if some speed modulation is applied from the outside, the speed/phase servo will not return to the speed servo.
If the speed/phase servo deviates significantly and the synchronization signal cannot be picked up, it will return to the rough servo.

(e) Examples Hereinafter, this invention will be explained in more detail with reference to Examples.

FIG. 1 is a block diagram of a CD player in which the present invention is implemented. However, parts unrelated to the rotation servo system are omitted from illustration. In FIG. 1, an optical disc 1 on which information to be reproduced such as music is recorded is rotated by a spindle motor 2, and the spindle motor 2 is driven by a driver 3. The driver 3 is controlled by a rotary servo system 4. Further, the information on the optical disc 1 is read by the optical pickup 5, and is read by the waveform shaping circuit 6.
The double signal waveform is shaped, and the signal is input to the digital signal processing circuit 8 via the synchronizing signal detection circuit 7.

The digital signal processing circuit 8 demodulates the EFM signal to obtain digital audio data and a parity code for error correction and detection. The results of the data processing here are subjected to other processing, such as D/A conversion processing (not shown), and then output. In addition, a PLL circuit 7.9 for clock reproduction and a reference signal generation circuit 10 for generating a reference clock CLK and the like are provided.

The rotary servo system 4 includes a rough servo circuit 1, a speed servo circuit 12, a phase servo circuit 13, and a selector 14 for switching and deriving the outputs of these servo circuits. The rough servo circuit 11 includes waveform shaping circuits 6 to E.
F M (Eight t.

(Forteen Modulation) signal and a clock signal CLK from the reference signal generation circuit 10,
The longest part of data in the EFM signal is LIT (T:
1/4.3218MHz)" = 2540 nS. The speed servo circuit 12 receives the synchronization signal 5YNC from the synchronization signal detection circuit 7, receives the clock signal CLK from the reference signal generation circuit 10, and Adjust the rotation speed so that the frame length is 5887 (approximately 136 nS).Phase servo circuit 1
3 receives a reference clock signal WFCK conforming to the PLL disk circuit from the synchronization signal detection circuit 7 and a reference clock signal RFCK for phase adjustment from the reference signal generation circuit 10, and matches the phase of the data with the phase of the reference signal. .

The selector 14 receives a synchronization signal continuous detection signal and a speed monitor from the synchronization signal detection circuit 7, and switches each output of the rough servo circuit 11, speed servo circuit 12, and phase servo circuit 13 depending on the detection status of these signals. This selector 14 outputs the 0th order to the driver 3.
The switching selection operation of the servo circuit will be explained with reference to FIG.

When the MS source is turned on, the rough servo is started first, and the output of the rough servo circuit 11 is given to the driver 3 via the selector 14. Eventually, when the synchronization signal is detected a predetermined number of times, the selector 14 switches the output to the speed servo circuit 12 and outputs it. Then, the rotational speed is monitored, and when the rotational speed falls within a specified range of, for example, 15%, the mode shifts to the speed/phase mode. In this mode, the output of the speed servo circuit 12 is still derived, the output of the phase servo circuit 13 is also derived, and the driver 3
In addition to servo control. If the servo is not disconnected, the operation continues in this mode. If, for example, the rotational speed deviates significantly due to some abnormality, the synchronization signal will not be picked up at all, and in this case, the system will return to the rough mode. That is, the selector 14 provides the output of the rough servo circuit 11 to the driver 3.

(f) Effects of the Invention According to this invention, when the servo is pulled in, once the speed/phase servo is entered, it is difficult to disengage, and even if speed fluctuation factors such as external sysmics enter, the speed/phase servo and the speed There is no reciprocating between servos, therefore there is less switching, and there are advantages of less jitter generation and less power consumption. Furthermore, when the servo comes off, it does not return to the rough servo via the speed servo, but immediately returns to the rough servo from the speed/phase servo, which has the advantage of being able to re-retract in a short time. be.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a CD player in which the present invention is implemented, FIG. 2 is a mode switching flow diagram of the rotary servo system of the same CD player, and FIG. 3 is a mode switching mode of the rotary servo system of a conventional CD player. FIG. 3 is a diagram showing a switching flow. 1: Optical disk, 2: 3: Driver, 4: 5: Optical pickup, 6: 7: Synchronous signal detection circuit, 9: 10 = Reference signal generation circuit, 11: Rough servo circuit, 12 Nispeed servo circuit, 13: Phase servo Circuit, 14 Spindle motor, rotating servo system, waveform shaping circuit, PLL circuit, :Selector.

Claims (1)

[Claims] (1) In a rotary servo system where each output of the rough servo circuit, speed servo circuit, and phase servo circuit is switched and outputted using a selector, the servo is pulled in in the order of rough servo, speed servo, and speed/phase servo. Rotary servo control method that controls from phase servo back to rough servo.