JPS6050774A - Generation system of magnetic head positioning information - Google Patents

Abstract

PURPOSE:To generate positioning information securely even if there is a defect in a disk surface by providing a means which extracts a defect indication signal from servo data and outputs a defect control signal and a peak holding circuit for a position information signal, and controlling the operation of the holding means with said control signal. CONSTITUTION:If there is a defect in a block 2 on the disk surface, a synchronizing signal Y2 to be recored in the block 2 is erased. Therefore, when servo data SV1 on the block 2 is supplied to a synchronizing signal extracting curcuit 10, a synchronizing signal SY is not extracted and no pulse P is generated. Consequently, capacitors 25 of respective peak holding circuits 13a-13d hold peak values when discharging is stopped according to the last peak holding operation (e.g. block 1). The peak holding operation of a block 3 is the same as that of the block 1. Thus, the circuits 13a-13d send output signals VA(-VD) shown in a figure, and the position signal of a head is generated on the basis of the signals.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for generating magnetic head positioning information in a magnetic disk device.

[Technical background of the invention and its problems]

Generally, in a magnetic disk drive, the positioning operation of the magnetic head (hereinafter simply referred to as head) is performed on the disk surface (
For example, a search is performed based on data recorded in a 100-page system.

The sensor data usually consists of a position information signal (hereinafter referred to as position bit), which is positioning data, and a synchronization signal for sampling the position bit. Serve data is serviced so that position bits for each area are divided into synchronization signal areas. recorded on the surface.

Incidentally, in order to position the head, it is necessary to read servo data from the disk and generate a position signal. To generate a position signal, a method is often used in which a peak value (hereinafter referred to as a peak value) of a position bit of servo data is sampled and a position signal is generated based on this peak value. However, with these methods, if there are defects such as magnetic state defects on the disk surface, especially in the position bit part, a normal peak value cannot be obtained, and as a result, the normal position signal cannot be obtained. There is a drawback that production is hindered. The above-mentioned defects on the disk surface are caused by variations in manufacturing and are therefore more than a few, and have become a serious problem, especially as the density of information recorded on disks has increased in recent years.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to provide a magnetic head positioning system that can reliably generate the front position signal necessary for positioning the magnetic head even if a defect exists in the position bit portion of the disk surface. The objective is to provide an information generation method.

[Summary of the invention]

In the present invention, a defect instruction signal indicating the presence or absence of a defect is written in each area in which a position information signal is placed on a disc on which sensor data is recorded.

This defect indication signal is extracted from the data by the defect extraction means. The peak hold circuit is a capacitor for holding the peak value of the position information signal (liii, charge and discharge control of this capacitor is based on a control signal corresponding to a defect instruction signal from the defect extraction means). It is configured as follows: As a result, even if there are defects on the disc surface, the This is because a stable peak value corresponding to the data digit 1'1 information signal can be held.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to all the drawings. FIG. 1 shows a sensor according to an embodiment. FIG. 2 is a block diagram showing the configuration of a decoding circuit. In FIG. 1, a synchronization signal extraction circuit 1o receives input of surze data SVJ read out from a disk surface not shown in the figure (surface 2) via a head.
This sir? The synchronization signal SY is extracted from the data Sv1.

Here, as shown in the data 5V71d, i3 diagram, position bits (AJ=-DJ, A;?~02, AJ~D3) for each area (Block 1~Block 3) and synchronization for sampling it. Signal (X1~X
,? , Y1 to Y3) S Y are arranged and recorded on the disk surface. In this case, the synchronization signal s corresponding to the area of the position bit where the defect exists
Delete y. The synchronization signal extraction circuit 10 usually consists of a converter/mother and a monostable, and the synchronization signal (third
When Y1 to Y and 9) SY in the figure are extracted, they are output to the *gurus generation circuit 11. This pulse generating circuit 11Fi outputs a pulse signal P which rises in synchronization with the synchronizing signal SY and falls immediately before the next synchronizing signal sy is generated. No J? The pulse generating circuit 11 includes a monostaple, and is configured to set its output at the falling edge of the synchronizing signal sy, and to set the time so that the pulse signal is generated until immediately before the next synchronizing signal SY.

The Sanzoringtz f pulse generation circuit 12 generates a synchronization signal SY and /? In synchronization with pulse signal P, sampling pulses TA-TD for sample-holding position pits A-D are output to each peak-hold circuit 13h-13d, respectively.

Each of the peak hold circuits 13a to 1.9d is a sensor? When data 5v2 (same as data Sv1 but with an appropriate positive DC offset) is supplied, each position bit A-D is set based on sampling pulses TA-TI) and pulse signal P. Operates to peak hold the peak value.

The peak hold circuits 13a to 13dJd are specifically circuits as shown in FIG. That is, the sampling pulse TA-TD is supplied to the NPN type emitter grounded transistor 20, and the power supply +v2 is supplied to the collector through the resistor 21. This power supply +v2 is also supplied to the emitter of a PNP type common collector transistor 22 via a resistor 21. Serp data SV2 is applied to this transistor 22 via a resistor 23. The NPN type train 6, cluster 24, has its base connected to the emitter of the transistor 22, and its collector supplied with a power supply v2. The capacitor 25 is connected to the power supply +v according to the operation of the transistor 24.
2 is supplied. One end of this capacitor 25 is grounded, and the other end is connected to an output terminal 26. Further, one end of an analog switch (for example, an N-channel MO8 transistor) 28 is connected to the other end of the capacitor 25 via a resistor 27f. The other end of the analog switch 28 is grounded, and the gate is controlled according to the operation of the NPN type emitter-grounded transistor 29, so that the analog switch 28 performs a switching operation. The transistor 29 has a collector supplied with the power supply +v1 via a resistor 301r, and a base supplied with the i4 pulse generation circuit 11.
A pulse signal P from is given.

In the above configuration, the operation according to the embodiment is performed in the third embodiment.
This will be explained with reference to the timing chart shown in the figure. First of all, lol
-1 Assume that a defect exists in position bits A2 to D2 of block 2 on the disk surface (serve surface). Then, the serve data SV2 read from the disk surface is given to peak hold circuits 13h to 13d. First, the sampling/'P pulse generation circuit 12
The peak hold circuit 1 responds to the sampling pulse TA from ? Position bit A of block 1 in FIG. 3 is supplied to a. In this case, as shown in FIG. 2, the sampling pulse TA (low level) turns off the transistor 20, and the position bit A1 of the serve data SV2 turns on the transistors 22 and 24. This allows Δ? The capacitor 25 is charged with a voltage corresponding to the wave height value (peak value) of the position bit AI.

When the amplitude of position bit A1 becomes smaller than the terminal voltage vA of capacitor 25, transistors 22 and 24 are turned off. Further, when the sampling pulse reaches a high level, transistor 20 is turned on and transistors 22 and 24 are maintained in an off state. At this time,·
Since the pulse signal P from the signal generating circuit 1 is at a high level, the transistor 29 and the analog switch 2
8 is turned on. Therefore, the charge stored in the capacitor 25 is discharged through the resistor 27 based on a predetermined time constant. Similarly, position B1 of block 1.
In the case of DI, the mocapacitor 25 is charged and discharged. No, in position bit CI, there is no output, so transistors 22 and 24 remain off, and capacitor 2
5 includes no charging.

Next, the peak hold operation of block 2 will be explained. As mentioned above, it is assumed that block 2 has a defect. In this case, in the present invention, the synchronization signal (Y2) that should originally be recorded in block 2 on the disk surface is deleted.

As a means of deleting such a synchronization signal, the server slices and monitors one position bit at a predetermined DC level during a read check after writing data, and determines whether or not extrinsic pulses or missing pulses occur. , an extra pulse or a missing pulse is generated, this can be achieved by removing the synchronizing signal Y of that block and rewriting. In addition, when writing data, the control of the position in the radial and circumferential directions of the disk surface is much more precise than that in normal data writing, and it is possible to rewrite the same information at the same position on the disk surface. is possible. Therefore, when the serve data Sv1 of block 2 is supplied to the synchronization signal extraction circuit 10, the synchronization signal SY is not extracted, and the pulse generation circuit 11 does not generate the i9 pulse signal P. Therefore, transistor 20 is on and transistor 29
and analog switch 28 remains off. Therefore, the capacitors 25 of each of the peak hold circuits 13a to 13d maintain the peak value at which they stopped discharging according to the previous peak hold operation (for example, block 1). Furthermore, since the peak hold operation of block 3 is similar to that of block 1, the explanation will be omitted.

As described above, output signals vA-VD as shown in FIG. 3 are output from each peak hold circuit 10-138 to 1.9d, and a head position signal is generated based on these signals VA to vr3. will be done. In this case, in the present invention, a predetermined area (block 2) on the disk surface is
If a defect exists in the position bit portion of , the peak value before the peak hold operation is maintained in each peak hold circuit 13a to 13d.

For this reason, in the conventional method, an unstable sampling pulse TA-TD (dotted line in Figure 3) is generated due to the defect, and the peak value vA-VD (Figure 3) fluctuates greatly compared to the normal peak value of block 1. (dotted line) may be output, but in the method of the present invention, block 1 is output as described above.
There is almost no fluctuation with respect to the peak value.

Therefore, even if there are defects on the disc surface,
Since large fluctuations in the peak value due to defects can be prevented, the adverse effects of defects on the generation of position signals can be largely prevented.

〔Effect of the invention〕

As detailed above, according to the present invention, even if a defect exists in the position bit portion of the disk surface, it is possible to prevent fluctuations in the peak value due to the defect and to hold a stable peak value of the position information signal. can. Therefore, a position signal can be reliably generated based on the peak value held as a result, and the positioning operation of the magnetic head can be performed accurately. Further, since even a disk with many defects can be used as a second surface, there is an effect that the manufacturing yield of the disk can be greatly improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a decoding circuit according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing a specific configuration of the peak hold circuit shown in FIG. 1, and FIG. 2 is a timing chart for explaining the operation of the server decoding circuit shown in FIG. 1. FIG. DESCRIPTION OF SYMBOLS 10... Synchronization signal extraction circuit, 11... Mother pulse generation circuit, 12... Sampling pulse generation circuit, 13a
~13d...Peak hold circuit. Applicant's agent Patent attorney Takehiko Suzue 13- Figure 1

Claims (1)

[Claims] A disk on which serve data consisting of position information signals of magnetic heads arranged in each of a plurality of areas and a defect instruction signal indicating the presence or absence of a defect in each area is recorded, and the server y1? read from this disk. a defect extracting means for extracting the defect instruction signal based on data and outputting a defect control signal; a capacitor for holding the peak value of the position information signal of the data; A magnetic head positioning information generation system comprising: a peak hold circuit including a control circuit that performs control based on the defect control signal.