JPS6381653A - Control method for rotary speed - Google Patents

Abstract

PURPOSE:To attain rotary control with constant linear velocity by generating a reference signal based on an address previously written in a disk and comparing with a reference signal corresponding to the rotational frequency of a motor rotating the disk. CONSTITUTION:An address decoder 2 detects an address signal among signals read from the disk D in a write/read means 1, and a CPU 3 generates the reference signal S1 corresponding to the position of the means 1. On the other hand, a motor 4 which rotates and drives the disk D incorporates with a frequency signal generator, which outputs a frequency signal corresponding to the rotational frequency of the motor 4, namely, the comparison signal S2. The signal S1 and the signal S2 are compared in a phase comparator 5. With a comparison signal S3 outputted from the comparator 5, the rotational frequency of the motor 4 is controlled. Thus, rotary control with a constant linear velocity is attainable.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method for controlling the rotational speed of a recording medium such as a disk.

Conventional technology A technique for recording information at a constant density by rotating a disk at a constant linear velocity (relative speed between the writing/reading means and the disk) is disclosed in Japanese Patent Publication No. 60-14421, for example.
Disclosed in the No.

When recording information on a disk, in order to control the rotation at a constant overall linear speed of the disk, it is necessary to adjust the position of the writing and reading means (optical) in the radial direction of the disk.
It is necessary to create a reference signal that is half-proportional. In the prior art described above, a potentiometer is used to create such a reference signal. However, with such a conventional configuration, an accurate reference signal cannot be obtained unless the potentiometer has a good value.

Further, the writing/reading means is started from a predetermined initial position (innermost track position), and each time the disk rotates, the color/return is added by 1, and based on this count value (for example, the count value is It is also possible to create the t-reference signal as described above (by converting it into a voltage-frequency converter), but with this method, if a counting error occurs, an accurate reference signal cannot be obtained. Repeated counting errors accumulate and cause the reference signal to become even more inaccurate.

Furthermore, when considering writable (additional recording or recording/erasing possible) electro-optical discs, the value of linear velocity is not uniquely determined depending on the material and purpose of the disc, and it is necessary to record at various linear velocities. In the prior art, it was difficult to change the circuit configuration in order to vary the linear velocity depending on the individual disks used.

＼Problems to be Solved by the Invention The present invention seeks to propose a rotation control method that can perform accurate rotation control at a constant linear velocity and can also easily change the linear velocity.

2. Means for solving the problem The present invention changes the frequency corresponding to the number of states by varying the number of states of a program executed by a microprocessor based on addresses written in advance on the disk. a step of obtaining a reference signal from a microprocessor, which corresponds to the number of rotations of a motor that rotates the disk, and a step of obtaining nine reference signals corresponding to the number of rotations of a motor that rotates the disk; and controlling the rotation of the motor based on a comparison signal between the reference signal and the reference signal. When the address recorded in advance on the disk is read out, this address indicates the position of the reading means in the disk radial direction at that time. Since it is accurately indicated, an accurate reference signal can be created based on this address. By the way, when creating a reference signal based on an address, the number of states of a program executed by a microprocessor is used, so by varying the number of states, it is easy to create reference signals with various frequencies. Can be created.

Embodiment FIG. 1 shows a block diagram of a device that implements the disk rotation control method according to the present invention. At least one address signal is prerecorded on the disk (D) in the form of, for example, a concave and convex pattern for one call. This address signal is recorded in a non-erasable manner. An address signal is detected by the address decoder (2) from among the signals read from the disk CD by the writing/reading means (1), and this address signal is detected by the microprocessor (3).
) is input. A reference signal (St) corresponding (inversely proportional) to the position of the V@ loading/reading means (1) is created by the microprocessor (3). -10,000, disk CD)? The motor (4) for rotating the motor (4) includes a frequency signal generator and has a frequency of 721. A frequency signal, that is, a comparison signal (S!) is output.The reference signal (Sl) and comparison signal (St) are compared in a phase comparator (5), and the comparison signal (S!) is output from the phase comparator (5). , ) control the rotational speed of the motor (4), thereby achieving a constant linear velocity.

Now, the method for creating the reference signal is as shown below.

Now, the linear velocity to be achieved is V (m/5ec), and the motor (
4) If the number of pulses output from the motor (4) corresponding to one rotation is E, and the frequency of the reference signal is f几(N), then fR■-2□R■×E...・・・・・・・・・・・・
...The relationship expressed by equation (1) holds true. However, R■
indicates the distance from the center of disk 0 to the writing/reading means (1).

The innermost recording track (T) from the center of the disc (CD)
If the distance to r1 is the recording track of the recording track and the D1 address is N, then R■-r+D@N・・・・・・・・・・・・・・・・・・
・・・・・・・・・(Period TR of the 21 type reference signal
From formula (1), T1 minus 1/ = 2r Ha ('') V-BxR (company)... (3
) expressionNow, if the address to be taken into the microprocessor (3) is in units of 100, then the address n is ()F
Dividing iN by 100 indicates the integer part when t. and r-
25x10 (m), D-1,6x10 (m)
Then, formula (2) is false) -25x10 +1.6x1
0 x 100 x bamboo = 25 x 10-3 + 1.6 x 10
−'x [rare].

Now, assuming V-2m/Jets E-72, the period T(0) of the reference signal at the innermost track is = 1.0
The cycle of the reference signal in the track of 9 x 10 (sec) and t1 address (N) TR uses a Z80At- that operates with a 4MHz clock as the microprocessor (3), and the above cycle is calculated by a micro7' processor ( Converting to the number of states, which is the instruction time in 3), if you create a program that creates a loop with states to set the duty of the reference signal pulse to 50, and execute this on the microprocessor (3), A reference signal having a frequency twice the predetermined frequency can be obtained, and by inputting this into a 7-pig/70-tube circuit and dividing the frequency by A, a reference signal having a predetermined frequency of duty 50 can be obtained.

FIG. 2 shows a flowchart for obtaining the fixed reference signal described above. The address (N) is in units of 9, 100, as described above. The time saving loop is a loop in which a program of explicit instructions (for example, an instruction to move the contents of a register) is repeatedly executed by the number of nine states.

In this embodiment, at least one address is provided for one track, but as mentioned above, the frequency of the reference signal is determined every 100 track calls. From this point of view, it is not necessary to provide an address for each track, but since the address is also used for searching recorded information, it is sufficient to take this point into account when providing the address.

Effects of the Invention As described above, according to the present invention, the reference signal is created by software based on the addresses recorded in advance on the disk, so the configuration is simple and there is no error when reading a single address. Even if an error occurs, if the next address can be read accurately, accurate rotation control can be performed again from then on, and the influence of one error will not continue until later.

Furthermore, for example, by recording information about the linear velocity of the disk in advance on the head of the disk and changing the number of program states accordingly, the linear velocity corresponding to each individual disk can be easily adjusted. It can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an apparatus for implementing the rotational speed control method according to the present invention, and FIG. 2 is a flowchart for generating a reference pulse signal. (1) is a writing/reading means, (2) is an address decoder, (3) is an I'm microprocessor, (4) is a motor, and (5) is a phase comparator. Figure 1

Claims (1)

[Claims] (1) A step of obtaining from the microprocessor a reference signal having a frequency corresponding to the number of states by varying the number of states of the program executed by the microprocessor based on the address written in advance on the disk. , a step of obtaining a reference signal corresponding to the number of rotations of a motor that rotates the disk; and a step of controlling the rotation of the motor based on a comparison signal between the reference signal and the reference signal. Control method.