JPH0585981B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for writing clock pulses onto a disk-type recording medium, and more particularly to an apparatus capable of accurately writing a desired number of clock pulses.

[Conventional technology]

When writing data at a precise position in the circumferential direction of the disk, such as when writing magnetic head positioning data (servo data) on the recording surface of a hard magnetic disk used as a servo disk, it is necessary to It is necessary to use a clock pulse of a specified frequency precisely synchronized with the reference frequency. Therefore, when writing servo data to a certain disk, the entire track on the recording surface on the opposite side of the disk or a certain track on the recording surface of another appropriate disk in the same disk pack must be written. A prescribed number of clock pulses are written in advance over the entire area, and writing is performed using the clock pulses read from the track as a reference.

As a method for writing such a specified number of clock pulses, for example, the following method has been conventionally adopted.

(1) A method of writing a specified number of clock pulses by controlling the oscillation frequency of an electrical clock pulse oscillator to a constant frequency according to the rotational speed of the disk.

(2) A rotation angle sensor, etc. that generates a pulse at each rotation angle that equally divides the circumferential angle (i.e. 360°) is attached to the disk rotation mechanism, and the sensor is synchronized with this pulse.
A method of writing a specified number of clock pulses using the output clock pulses of a PLL circuit.

(3) A method of writing a specified number of clock pulses using the output clock pulses of a PLL circuit synchronized with a signal such as an index signal that is applied every time the disk rotates.

[Problem that the invention seeks to solve]

However, in method (1) above, since the rotation of the disk and the frequency of the clock pulses are asynchronous, it is often impossible to write the specified number of clock pulses accurately due to unevenness in the rotational speed of the disk.
I had to rewrite it many times until I got it right. In addition, in method (2) above, it may be necessary to use a rotation angle sensor with a different resolution depending on the difference in the specified number of values, and depending on the specified number of values, it may be necessary to use a rotation angle sensor with a corresponding resolution. There were times when it was not possible to prepare an angle sensor. Furthermore, in the method (3) above, since the synchronization is only performed with a signal applied once per revolution, the intervals between the written pulse trains are often uneven.
As described above, with all conventional methods, it is difficult to write a specified number of clock pulses accurately and efficiently, and therefore it is difficult to write servo data at accurate positions based on this. It was hot.

This invention was made in view of the above points,
It is an object of the present invention to provide a clock pulse writing device that can accurately and efficiently write a desired number of clock pulses to a disk.

[Means for solving problems]

The clock pulse writing device according to the present invention includes:
rotation synchronization pulse generating means for generating a predetermined number (Mx) of rotation synchronization pulses per rotation of the disk type recording medium in synchronization with the rotation of the disk type recording medium;
Divide the desired number of pulses (M) to be written in one rotation of the disk type recording medium by a predetermined integer (N) to obtain the quotient (a) and remainder (b), and use this quotient (a) to calculate the number of pulses written in the integer. means for determining the number (a) of blocks consisting of the number of pulses corresponding to (N), the ratio (Mx/M) of the predetermined number (Mx) and the desired number of pulses M, the quotient (a) and the remainder According to (b), a means for executing the following formula [{Mx-(b×Mx/M)}/a]=e remainder f, and a means for executing the quotient (e) of the above formula by the rotation synchronization for each block. The reference number of pulses is taken as the number of blocks corresponding to the remainder (f) of the above formula, and the number (e+1) obtained by adding 1 to the reference number (e) is assigned to each of these blocks, and the remaining number is means for allocating the reference number (e) to each block, and means for sequentially counting the number of rotation synchronization pulses and assigning the number (e or e+) to each block.
1) a means for generating a block pulse every time the block pulse is reached, and a pulse oscillation period variable for each block period so as to generate clock pulses corresponding to the predetermined integer (N) in one block period in synchronization with the block pulse; A phase-locked loop type clock pulse oscillation means for oscillating the clock pulse while controlling the clock pulse, and a writing means for writing the clock pulse generated from the clock pulse oscillation means onto the disk type recording medium, desired number of pulses (M
This is characterized in that clock pulses of =a×n+b) can be written as evenly as possible.

[Effect]

The desired number M of pulses to be written in one revolution of the disk type recording medium is divided into a blocks each having a number of pulses corresponding to a predetermined integer N, and the number of rotation synchronizing pulses e or e corresponding to each block period is divided into a blocks.
+1 is required. In other words, the rotation synchronization pulse is
If the oscillation period of the clock pulse is variably controlled so that N clock pulses are generated for each block of clock pulses or e+1 clock pulses, the number of clock pulses per revolution becomes a×n+b=M,
A desired number of clock pulses (M=a×n+b) can be written as evenly as possible. Note that the number of pulses corresponding to the remainder b is automatically oscillated at a period corresponding to the last block period because the clock pulse oscillation means is of a phase-locked loop type.

In this way, since the number of pulses Mx generated by the rotation synchronization pulse generating means corresponds to one rotation of the disk, the number of Mx pulses generated from the clock pulse oscillating means is Clock pulses are written by the writing means to the disk (or to another disk rotating synchronously with the disk) during every revolution of the disk. This allows the desired M
The clock pulses can be accurately and efficiently written to the disk, and since the writing is performed in synchronization with the rotation of the disk, the clock pulses can be written without being affected by uneven rotation.

Incidentally, the number of pulses Mx generated by the pulse generating means may be an appropriate number, so that such a pulse generating means can write an appropriate number of clock pulses to the disk using, for example, an electric clock pulse oscillator and read out the disk. Even by doing,
It can also be easily realized by attaching a rotation angle sensor having an appropriate resolution to the disk rotation mechanism.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a clock pulse writing device according to the present invention. This clock pulse writing device 1 writes a specified number of clock pulses to disk 24 of hard magnetic disks 24 and 25 in the same disk pack.

In the writing device 1, a crystal oscillator 2 generates clock pulses of constant frequency. crystal oscillator 2
The clock pulses generated from the write circuits 3 and 9 are supplied to the write circuits 3 and 9. The write circuit 3 outputs a clock pulse having a portion interrupted for a certain period of time based on the applied clock pulse.
This clock pulse output from the write circuit 3 is applied via a write amplifier 4 to a read/write head 5 corresponding to a certain recording surface of the disk 24. This clock pulse is written to the disk 24 by the head 5, overwriting the entire area of a certain track.

The signal read out by the head 5 from the track of the disk 24 is applied to a pulse forming circuit 7 via a read amplifier 6, and is waveform-shaped by the pulse forming circuit 7 to become a pulse signal as shown in FIG. 2a. After being converted, it is applied to the index detection circuit 8. The index detection circuit 8 outputs an index pulse as shown in FIG. 2b in response to interruption of the pulse signal for a certain period of time while the pulse signal is being applied from the pulse generation circuit 7. This index pulse is applied to the control input C of the write circuit 9.

Based on the applied clock pulse and using the index pulse as a signal, the write circuit 9, like the write circuit 3, detects a portion interrupted for a certain period of time while the disk 24 (and therefore also the disk 25) just rotates once. It outputs a clock pulse having a certain value. This clock pulse outputted from the write circuit 9 is applied via a write amplifier 10 to a read/write head 11 corresponding to a certain recording surface of the disk 25. On disk 25,
Head 11 writes this clock pulse over the entire area after a certain track.

The signal read out by the head 11 from the track of the disk 25 is given to the pulse forming circuit 13 via the read amplifier 12, and is waveform-shaped by the pulse forming circuit 13 to become a pulse signal as shown in FIG. 2c. After being converted, it is applied to the index detection circuit 14 and the PLL circuit 15 with an internal frequency division ratio of "1". The index detection circuit 14, like the index detection circuit 8, outputs an index pulse in response to interruption of the pulse signal for a certain period of time while the pulse signal is being applied from the pulse generation circuit 13. PLL circuit 15
outputs a pulse signal with the same frequency as the applied pulse signal (see Figure 2e). PLL circuit 15
The pulse signal output from the index detection circuit 14 is applied to the counter 16, and the pulse signal output from the index detection circuit 14 is applied to the control input C of the counter 16. Using the index pulse as a signal, the counter 16 counts the pulse signal applied from the PLL circuit 15 while the disk 25 rotates once or more. A signal indicating the count value Mx of the counter 16 is given to the CPU 17.

The CPU 17 uses a preset desired number of pulses M per disk rotation and a frequency divider 2 to be described later.
A frequency division ratio N of 1 is stored, and these values are used to perform arithmetic processing as shown in FIG. 3 regarding the count value Mx for one disk rotation given from the counter 16. In FIG. 3, first, in step 101, the number of pulses M is divided by the frequency division ratio N to obtain a quotient a and a remainder b (both a and b are integers) as the number of blocks per revolution of the disk. Next, in step 102, the remainder b obtained in step 101 is added to the ratio of the count value Mx and the number of pulses M.
Multiply Mx/M to find the product c+d (where c is the integer part of the product and d is the decimal part of the product). Next, in step 103, it is checked whether the decimal part d of the product obtained in step 102 is greater than or equal to "0.5". If d is “0.5” or more, judge YES and proceed to step.
The process proceeds to step 104, where the product of b and Mx/M is set to c+"1," and then the process proceeds to step 106. On the other hand, if d is less than "0.5", it is determined as NO and the process proceeds to step 105.
Step 106 sets the product of b and Mx/M to c, and then proceeds to step 106. In step 106, b and
Product of Mx/M (i.e. c or (c+
"1")) is subtracted from the count value Mx and divided by the number of blocks a per disk rotation determined in step 101, and the quotient e and remainder f (both e and f are integers) are determined. When step 106 is completed, the process proceeds to step 107, where the number of blocks in which the number of pulses in one block is e is determined as (a-f), and the number of blocks in which the number of pulses in one block is (e + "1") is f. The remainder obtained in step 106 is distributed to each block on average so that

A signal indicating this calculation result of the CPU 17 is applied to the control input C of the programmable divider 18. In addition, this programmable divider 18 includes
A pulse signal output from the PLL circuit 15 is given. Programmable divider 18 is CPU1
Based on the calculation result of step 7, as shown in FIG. 4a and b, e or (e+
The output pulse signal of the PLL circuit 15 is frequency-divided by outputting a block pulse every time "1" pulse is applied. In this way, from the programmable divider 18, during one rotation of the disk 25 (and therefore also the disk 24), the a
block pulses are output.

The block pulse output from the programmable divider 18 is applied to a phase detector 20 within the PLL circuit 19. In the PLL circuit 19, the phase detector 20 compares the phase of the output signal of the frequency divider 21 with the internal frequency division ratio N with this block pulse signal, and as a result, the VCO 22 outputs the signal as shown in FIG. 4c. A clock pulse is output which is synchronized with the block pulse signal and has a frequency N times that of the block pulse signal.

This clock pulse output from the VCO 22 is given to the write circuit 23. light circuit 2
The index pulse outputted from the index detection circuit 14 is applied to the control input C of No. 3.
The write circuit 23 uses the index pulse as a signal to write the data on the disk 25 (and therefore also on the disk 24).
) It outputs the given clock pulse as it is during just one revolution. This clock pulse output from the write circuit 23 is applied to the head 5 via the write amplifier 4. In the head 5, this clock pulse is written over a certain track of the disk 24 while the disk 24 rotates once or twice.

In the writing device 1 having the above-described configuration, first, when writing of a signal to the disk 24 is completed and an index pulse is obtained from the index detection circuit 8 based on the read signal, this index pulse is used as a signal to A clock pulse of a specified frequency output from the crystal oscillator 2 is written over a certain track of the disk 25. However, the count value Mx of the output pulse signal of the PLL circuit 15 based on the read signal of the disk 25 is usually a value different from the desired number of pulses M per one rotation of the disk due to unevenness in the rotational speed of the disk 25. (For example, M=
For example, Mx = ``103000'' for ``100000'' (see Figure 5a)).

The CPU 17 performs arithmetic processing as shown in FIG. 3 described above regarding this count value. That is,
For example, if the internal frequency division ratio of the PLL circuit 19 is "128", the CPU 17 first performs the calculation in step 101 as follows: M/N=100000/128=781 remainder 32, and the value of a is "781", and the value of b is "781". Find the value "32". Next, in step 102, the calculation b×Mx/M=32×103000/100000=32.96 is executed, and the value of c is “32” and the value of d is “0.96”.
seek.

Next, in step 103, since 0.96>0.5
If it is determined to be YES, the process proceeds to step 104, sets b×Mx/M=c+1=33, and proceeds to step 106. In step 106, (Mx-b・Mx/M)/a=103000-33/781=131 remainder 656 is calculated, and the value of e is "131" and the value of f is "656".
seek. Finally, in step 107, the remainder "656" is averaged so that the number of blocks in which the number of pulses in one block is "131" is "125" and the number of blocks in which the number of pulses in one block is "132" is "656". Allocate to each block.

From programmable divider 18, this
Based on the calculation results of the CPU 17, the disk 24,
During one rotation of 25, the disk 24,
781 block pulses synchronized with 25 rotations are output (see FIG. 5b).

The PLL circuit 19 outputs a clock pulse having a frequency 128 times that of this block pulse signal (see FIG. 5c) in synchronization with this block pulse signal. This clock pulse is written across a certain track of disk 24 during just one revolution of disk 24. That is, at this time, the disk 24 has 781×128+32=100000 pieces as shown in FIG. 5c (generally, a×N+ as shown in FIG. 4c)
A pulse signal having a number of pulses (b=M) is written, thereby making it possible to write a preset desired number of clock pulses to the disk evenly, accurately, and efficiently.

In this embodiment, a clock pulse of a predetermined frequency is written across a certain track of the disk 25, and the recorded contents of the disk 25 are read out to obtain a pulse signal synchronized with the rotation of the disk. For example, such a pulse signal may be obtained by attaching a rotation angle sensor having an appropriate resolution to the disk rotation mechanism.

〔Effect of the invention〕

As described above, according to the clock pulse writing device for a disk type recording medium according to the present invention,
Since the desired number of clock pulses are written in synchronization with the rotation of the disk, the desired number of clock pulses can be written evenly, accurately, and efficiently even if the rotational speed of the disk is uneven. Therefore, by using, for example, a clock pulse read from this disk-type recording medium as a reference, servo data can be easily written at an accurate position on the disk-type recording medium used as a servo disk.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the clock pulse writing device according to the present invention, and FIG. 2 is a timing chart showing an example of output signals of each part in FIG. , b shows an example of the output index pulse of the index detection circuit 8, c shows the output pulse signal of the pulse generator 13, d shows the output index pulse of the index detection circuit 14, and e shows an example of the output pulse signal of the PLL circuit 15. FIG. 3 is a flowchart schematically showing the arithmetic processing program executed by the CPU 17 in the same embodiment, and FIG. 4 is a timing chart showing another example of output signals of each part in FIG. the output pulse signal of the circuit 15;
b is the output block pulse of the program divider,
5a to 5c are timing charts showing specific examples of the relationships among the signals shown in FIGS. 4a to 4c. 1... Clock pulse writing device, 2... Crystal oscillator, 3, 9, 23... Write circuit, 4, 10
...Write amplifier, 5,11...Read/write head, 6,12...Read amplifier, 7,13...
... Pulse circuit, 8, 14 ... Index detection circuit, 15, 19 ... PLL circuit, 16 ... Counter, 17 ... CPU, 18 ... Programmable divider, 20 ... Phase detector, 21 ... Frequency division Equipment, 22...VCO, 24, 25...Hard magnetic disk.

Claims (1)

[Scope of Claims] 1. Rotation synchronization pulse generating means for generating a predetermined number (Mx) of rotation synchronization pulses per rotation of the disk type recording medium in synchronization with the rotation of the disk type recording medium, and said disk type recording medium. Divide the desired number of pulses (M) to be written in one revolution by a predetermined integer (N) to find the quotient (a) and remainder (b), and calculate the value corresponding to the integer (N) by this quotient (a). means for determining the number (a) of blocks consisting of the number of pulses to Therefore, a means for executing the following formula [{Mx-(b×Mx/M)}/a]=e remainder f, and the quotient (e) of the above formula is used as the reference number of the rotation synchronization pulses for each block. , the number of blocks corresponding to the remainder (f) of the above equation is arbitrarily selected, and for those blocks, the number (e
+1) to each block, and means to allocate the reference number (e) to each of the remaining blocks; and means for sequentially counting the number of rotation synchronization pulses and counting each time the number (e or e+1) assigned to each block is reached. means for generating block pulses; and means for generating the clock pulses while variably controlling the pulse oscillation period for each block period so as to generate clock pulses corresponding to the predetermined integer (N) in one block period in synchronization with the block pulses. A phase-locked loop type clock pulse oscillation means for oscillating, and a writing means for writing clock pulses generated from the clock pulse oscillation means onto the disk type recording medium, the clock pulse oscillation means generating a desired number of pulses per rotation of the disk type recording medium. 1. A clock pulse writing device for a disk type recording medium, characterized in that clock pulses of M=a×n+b can be written as evenly as possible.