JPH0810887Y2 - Rotating recording medium recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a rotary recording medium recording / reproducing apparatus, and includes two tracking servo signals on a rotary recording medium of an embedded servo system (for example, a magnetic disk, hereinafter referred to as “disk”). The present invention relates to a rotary recording medium recording / reproducing device for selecting and writing each of the required frequencies.

2. Description of the Related Art Conventionally, there is an embedded servo type magnetic disk in which a tracking servo signal is written on a data recording surface on which an information signal is written. In such a magnetic disk, a plurality of servo sectors in which tracking servo signals are written are arranged at every predetermined angular range or every predetermined interval.

FIG. 6 shows a schematic perspective view of an example of a main part of a conventional rotary recording medium recording / reproducing apparatus. In the figure, a plurality of magnetic disks 1a
1e are arranged at predetermined intervals along the shaft 2, and are rotated in the direction of arrow A together with the shaft 2.
On the other hand, the head positioning unit 3 causes each of the magnetic disks 1a to 1e.
Magnetic heads 4a ₁ to 4 arranged on both signal recording surfaces of
The e ₁ and 4a _{2 to} 4e ₂ are moved together with the head positioning portion 3 in the directions shown by the arrows B and C, whereby each magnetic disk 1a is moved.
Data is written to and read from ~ 1e. In this case, for example, a tracking servo signal is written at predetermined intervals along at least one of the signal recording surfaces 1a ₁ and 1a ₂ of the magnetic disk 1a along the circumferential direction of the magnetic disk as indicated by a broken line S.

Here, on the signal recording surface 1a ₁ of the disk 1a, for example as shown in Figure 7, circumferential, etc. servo sectors S ₁ to S ₈ and data sectors D ₁ to D ₇ and the like each disc Recording tracks are alternately formed at predetermined intervals along the track.

Tracking servo signals T ₁ and T ₂ having different frequencies are written in the servo sectors S _{1 to} S _{8 and the} like adjacent to each other in the radial direction of the disk with the center of the track as a boundary. On the other hand, a synchronization signal (Sync), an index signal (ID), data (Data), an error correction code (ECC) and the like are written in the data sectors D _{1 to} D _{7 and the} like.
In addition, the above ID is the address mark (AM), cylinder number (CYLH and CYLL), head number (HD), sector number (SE
C) and CRC (Cyclic Redundancy Check Code).

By the way, various signals written on the disc are subjected to, for example, MFM (Modified Frequency Modulation) modulation, and the frequency component of the signal is composed of a finite number of basic spectra with a certain frequency as the least common multiple. Further, the frequencies of the tracking servo signals T ₁ and T ₂ are also written on the disk at any of the fundamental spectrum frequencies among the above frequencies.

Next, when the disk is reproduced, a servo gate pulse synchronized with the tracking servo signal is generated, and the reproduction tracking servo signal is extracted from the reproduction signal of the disk by this servo gate pulse. Therefore, as is well known, the magnetic head 4a _{1 and the} like are moved in the direction of arrow B or C by the head positioning unit 3 so that the frequency components of the reproduction tracking servo signals T ₁ and T ₂ become equal. As a result, the magnetic heads 4a _{1 and the} like are always controlled to be accurately located at the on-track position.

However, in the above-mentioned conventional rotary recording medium recording / reproducing apparatus, the rotation fluctuation of the spindle motor for rotating the disk and the rotational speed of the disk provided for generating the servo gate pulse are detected. There is a possibility that the servo gate pulse synchronized with the cycle of the tracking servo signal and the cycle of the reproduction tracking servo signal may deviate due to the malfunction of the sensor and the circuit, and their noise resistance.

Therefore, if the digitally modulated information signal is written in the data sector at the same frequency as the tracking servo signal, the information signal is mistaken as a reproduction tracking servo signal through a frequency selection circuit or the like for extracting the reproduction tracking servo signal. There was a problem that the output was made and a tracking error occurred.

Therefore, an object of the present invention is to provide a rotary recording medium recording / reproducing apparatus which solves the above problems by writing different frequencies of a digitally modulated information signal and a tracking servo signal on a disc.

Means for Solving the Problems The rotary recording medium recording / reproducing apparatus according to the present invention has one oscillator and a first frequency-divided information signal frequency obtained by dividing the frequency of each signal obtained from the oscillator. Means for generating a first tracking servo signal having a frequency and a second tracking servo signal having a second frequency different from the frequency of the digitally modulated information signal, and recording tracks for the first and second tracking servo signals, respectively. Means for writing adjacent to each other in the radial direction of the rotating recording medium in the upper servo sector, wherein the first and second frequencies are frequencies given as least common multiples of all fundamental spectra of the digitally modulated information signal frequency. N (where n is a natural number) times the frequency, and is selected as a frequency different from all the basic spectra. .

Operation The first and second frequencies are set so as to be different from the digitally modulated information signal frequency. Further, the first and second tracking servo signals are written next to each other in the radial direction of the disk in the servo sectors on the recording tracks of the disk.

Embodiment FIG. 1 shows a block system diagram of an embodiment of a recording system of a rotary recording medium recording / reproducing apparatus according to the present invention. Before explaining this embodiment, first, the mechanical structure of the device of the present invention will be briefly described with reference to FIG.

FIG. 2 shows a sectional view of the device of the present invention, which is a disk.
Reference numeral 11 is fixed by a disk holder 15 to a disk rotation drive motor (spindle motor) including a stationary shaft 12, a magnet 13, coils 14a, 14b and the like. This disk rotation drive motor is configured so that the disk holder 15 and the like rotate about the stationary shaft 12, and as a result,
The disk 11 is rotated. Also, flexure 16
Heads (sliders) 18a and 18b fixed to the carriage 17 by a and 16b are floating magnetic heads and are arranged to face both signal recording surfaces of the disk 11.

On the other hand, the rack 20 fixed to the lower ends of the pinion 19 and the carriage 17 is meshed with each other, and the carriage 17 and the heads 18a and 18b fixed to the rack 20 by the rotation of the pinion 19 are engaged.
Etc. are moved in the direction of arrow D or E. By controlling the rotation angle of the pinion 19 by a small amount based on the tracking servo signal, tracking control of the heads 18a, 18b is performed.

Now, as shown in FIG. ₃ , three basic spectra P ₁ , P ₂ and P ₃ of the MFM-modulated information signal to be recorded on the disk 11 are respectively 1F, (4/3) F and 2F (however, F Indicates a predetermined frequency. For example, if 1F = 800kHz, (4/3) F≈1.06M
Hz, 2F = 1.6MHz). In this case, if any _two basic spectra of the above three basic spectra P ₁ , ₂ , P ₃ are selected as the two tracking servo signal frequencies, the tracking error will occur as described above.

Therefore, the present invention is characterized in that the basic spectrum and the tracking servo signal frequency are different from each other, and a method of selecting an example of the tracking servo signal frequency will be described below.

First, the frequency 4F (= 3.2 MHz), which is the least common multiple of the three basic spectrum frequencies 1F, (4/3) F, and 2F, is obtained. In this case, the frequencies 1F, (4/3) F, 2F are values obtained by dividing the frequency 4F by 1/4, 1/3, 1/2 as shown in the table below. Next, when the frequency 8F (= 6.4MHz) that is twice the frequency of the least common multiple is obtained, the frequencies 1F, (4/3) F, 2F are 1/8, 1/6, 1 /
The value is divided by 4. In this case, frequency 1F, (4/3) F, 2
Frequency f ₁ divided by frequency 1/8 and frequency 1/5 within the range of F ₁
And f ₂ (f ₁ ≈ 0.91 MHz, f ₂ = 1.28 MHz) exist. Therefore, if the frequencies f ₁ and f ₂ are selected as the frequencies of the _two tracking servo signals T ₁ and T ₂ , respectively, as shown in the table below, the occurrence of the tracking error as described above can be prevented.

Next, the recording system of the device of the present invention will be described with reference to FIG. Here, the oscillator 21 has a crystal oscillator 22,
Generate a signal of frequency 8F (= 6.4MHz), which is equivalent to twice the least common multiple of the fundamental spectrum frequency of the book, and generate 1 / N frequency divider 23.
And to the 1 / M frequency divider 24, respectively.

The frequency division ratios 1 / N and 1 / M of the frequency dividers 23 and 24 are selected to be 1/7 and 1/5, respectively.
The tracking servo signal T _{1 of the} frequency f ₁ (= 8F / 7≈0.91MHz) is generated from 23, while the tracking servo signal T ₁ of the frequency f ₂ (= 8F / 5 = 1.28MHz) is generated from the frequency divider 24. The signal T ₂ is generated. This tracking servo signal T ₁ ,
T ₂ is supplied to the terminals 25a and 25b of the switch circuit 25, respectively.
This switch circuit 25 is a tracking servo signal control device.
Switching control is performed by a control signal from 26, and either _{one of} the tracking servo signals T ₁ and T ₂ is output to the terminal 27a of the switch circuit 27 as described later.

On the other hand, the information signal generator 28 generates an MFM-modulated information signal and outputs it to the terminal 27b of the switch circuit 27. Further, the write signal switching device 29 generates a switching signal corresponding to the servo gate pulse coming from the terminal 30 and supplies the switching signal to the switch circuit 27 for switching control.

Therefore, the switch circuit 27 selectively outputs either the output tracking servo signal of the switch circuit 25 or the digitally modulated information signal according to the switching signal. The output signal of the switch circuit 27 is sent to the head 13 via the terminal 31.
The signals are supplied to a, 13b, etc., and thereby a write signal composed of the digitally modulated information signal and the tracking servo signal is written on the disk 11.

Next, the signal writing procedure to the disk 11 will be described with reference to FIG. First, the switch circuit 25 is connected to the terminal 25a side, while the switch circuit 27 is connected to the timing terminal 27a side according to the servo gate pulse, whereby the tracking servo signal T ₁ is transmitted to the disk.
Writing is performed at predetermined intervals over the entire 11 signal recording surfaces.

After that, the switch circuit 25 is connected to the terminal 25b side,
This time, the tracking servo signal T ₂ is written at positions adjacent to each other in the radial direction of the disk 11 with respect to the already written tracking servo signal T ₁ . As a result, the servo sectors S _{1 to} S _{8 and the} like are recorded by forming concentric tracks on at least one signal recording surface of the disk 11.

Next, the switch circuit 27 is connected to the terminal 27b side at the timing corresponding to the servo gate pulse, and by the operation of the tracking servo circuit 46 and the like described later. Head based on already recorded tracking servo signals T ₁ and T ₂
18a, tracking control 18b is the digital modulated information signal while performed is written as intermittently data sectors D ₁ to D ₇ and the like concentrically track on the disk 11.

Next, the tracking servo system of the device of the present invention will be described with reference to FIG.
Of the 11 signal recording surfaces 11a, 11b, the servo
Sectors S ₁ , S _2, etc. shall be recorded and formed. Further, this tracking servo system is used to control the heads 13a and 13b so as to always be in the on-track position at the time of writing and reading the information signal. The operation will be described.

Here, on the signal recording surface 11a of the disk 11, the digitally modulated information signal is a tracking servo signal St (here,
The tracking servo signals T ₁ and T ₂ are collectively referred to as St) and are written in the format as shown in FIG. 7, while only the information signal is recorded on the signal recording surface 11b at predetermined intervals. It has been written. In this case, when the disk 11 is reproduced, the heads 18a and 18b respectively move to the fifth position.
Reproduced signals a and b as shown in FIGS. 7A and 7B are obtained and output to the amplifier and head selection circuit 41.

On the other hand, the pulse generator 42 generates a servo gate pulse c as shown in FIG. 5C at the timing synchronized with the reproduction tracking servo signal St in the reproduction signal a and outputs it to the amplifier and head selection circuit 41. This amplifier and head selection circuit 41 extracts a reproduction tracking servo signal St as shown in FIG. 5 (D) from the reproduction signal a based on the incoming servo gate pulse c and outputs it as a signal d. Output to.

The frequency selection circuits 43 and 44 constitute a band-pass filter having the characteristics shown by W ₁ and W ₂ in FIG. 3 and a detection circuit for detecting the filter output signal, and a tracking servo circuit 46 together with a comparator 45. From the incoming signal d, the reproduction tracking servo signals T ₁ and T ₂ are frequency-selected by a band-pass filter, respectively, taken out, subjected to envelope detection by a detection circuit, and then outputted to the comparator 45.

The comparator 45 generates a tracking control signal according to the level difference between both incoming detection signals, supplies the tracking control signal to the drive motor of the pinion 19 via a terminal 47, and controls the rotation angle thereof. Thereby, as described above, the heads 18a and 18b are controlled so as to always be in the on-track position.

The configuration of the device of the present invention is not limited to the one for writing and reading the information signal on one disk 11 as shown in FIG. 2, and for example for writing and reading the information signal on many disks as shown in FIG. The configuration may be such that reading is performed. The method of selecting the two tracking servo signal frequencies described above is not limited to the method described in the present embodiment, and all basic spectra of the information signal and the two tracking servo signal frequencies may be different from each other. Any method may be used as long as it can be selected.

Therefore, the modulation / demodulation method of the information signal is not the MFM modulation / demodulation method described in the present embodiment, but may be (2,7) RLL (Run Length).
Limited) code modulation / demodulation method (for example, described in Nikkei Electronics, August 3, 1981, no.270, pp106-119), etc., when all spectrum intervals are short, all basic spectra The two tracking servo signal frequencies may be selected to be lower than the lowest frequency of the above or higher than the highest frequency thereof.

Further, the signal writing means for the disk 11 (that is, the switching timing of the switch circuits 25 and 27) is not limited to the procedure described in the present embodiment, and may be another procedure. The disk on which the information signal and the like are written and read by the device of the present invention is not limited to the hard disk, but may be a floppy disk or a recordable / reproducible optical disk.

Effect of the Invention As described above, according to the present invention, the frequency of the digitally modulated information signal and the tracking servo signal are made to be different from each other and written to the disc, so that only the reproduction tracking servo signal is easily reproduced from the reproduction signal of the disc. Therefore, the head tracking control can be surely performed without generating the tracking error described above, and the output signal of one oscillator can be divided to simplify the operation. In addition, since two tracking servo signals having a frequency different from the frequency of the digitally modulated information signal can be obtained, the device of the present invention can be realized with a simple and inexpensive circuit configuration, and the target signal is digitally modulated. Since it is a signal, the frequency of the servo signal is in and out of the band compared to that for analog modulation. It has the features that it can be set regardless of whether or not it is easy to perform circuit design.

[Brief description of drawings]

FIG. 1 is a block system diagram showing an embodiment of a recording system of a rotary recording medium recording / reproducing apparatus according to the present invention, FIG. 2 is a sectional view showing a mechanical structure of the apparatus of the present invention, and FIG. Frequency spectrum diagrams of various signals written on the disk, FIGS. 4 and 5 (A) to (D) are a block system diagram showing an embodiment of the tracking servo system of the device of the present invention and signal waveforms for explaining the operation thereof, respectively. FIG. 6 is a schematic perspective view of an example of a main part of a conventional rotary recording medium recording / reproducing apparatus, and FIG. 7 is a schematic diagram showing a general data format. 11 ... Disc, 11a, 11b ... Signal recording surface, 12 ... Stationary shaft, 13 ... Magnet, 14a, 14b ... Coil, 15 ... Disc holder, 16a, 16b ... Flexure, 17 ... Carriage, 18a, 18b
… Head (slider), 19… Pinion, 20… Rack, 21
Oscillator, 22 ... Crystal oscillator, 23 ... 1 / N frequency divider, 24 ... 1 / M frequency divider, 25, 27 ... Switch circuit, 26 ... Tracking servo signal controller, 28 ... Information signal generator, 29 ... write signal switching device, 30 ... servo gate pulse input terminal, 31 ... write signal output terminal, 41 ... amplifier and head selection circuit,
42 ... Pulse generator, 43, 44 ... Frequency selection circuit, 45 ... Comparator, 46 ... Tracking servo circuit, 47 ... Tracking control signal output terminal.

Claims (1)

[Scope of utility model registration request] 1. A rotary recording for controlling a head to always be in an on-track position based on two tracking servo signals having different frequencies written together with a digitally modulated information signal on at least one signal recording surface of a rotary recording medium. In a medium recording / reproducing apparatus, one oscillator, a first tracking servo signal having a first frequency different from a digitally modulated information signal frequency obtained by frequency-dividing a signal obtained from the oscillator, and the digitally modulated signal. A means for generating a second tracking servo signal having a second frequency different from the information signal frequency, and a radius of the rotating recording medium for each of the first and second tracking servo signals in a servo sector on a recording track. Means for writing adjacent to each other in the direction, the first and second frequencies being respectively the digitally modulated signal. It is obtained by dividing the frequency of n (where n is a natural number) times the frequency given by the least common multiple of all the basic spectra of the report signal frequency, and is selected as a frequency different from all the basic spectra. A rotary recording medium recording / reproducing apparatus characterized in that.