JPS58208928A - Writing system of position signal on floppy disk - Google Patents

Abstract

PURPOSE:To adjust easily and with high accuracy a position shift of a head, by inclining a gap of the head against the center of a disk and writing a reference position signal. CONSTITUTION:A reference position signal of wavelength lambda is recorded by inclining a reference head 1 by b/a against the center of a disk. When this recording is read by a practical head 2 of a position shift (e), the maximum read-out output EP corresponding to magnitude and a direction of the shift (e) for satisfying the equation I is measured, and in accordance with this measured result, the position shift of the head can be adjusted easily and with high accuracy. In this regard, K is a constant corresponding to (a), (b), etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention The present invention relates to a floppy disk position signal writing method, and in particular to a method for detecting the amount of positional deviation of a head at any time with respect to a reference medium used for tracking adjustment of a Fronbie disk device, etc. The present invention relates to a method for writing position signals.

Prior Art When manufacturing a floppy disk device, it is necessary to align the head position of the floppy disk device with a reference on the medium in order to provide a compatible frame for the medium. For this purpose, there are conventionally the following two methods. One method is to mechanically measure and adjust the head position from the center of the media rotation spindle, and the other method is to write a highly accurate position signal on the reference medium and adjust the floppy disk. This is a method of adjusting the position of the head by attaching it to a device and detecting a position signal written on the medium. The latter adjustment method using a reference medium uses a highly precisely positioned head 1, writes a signal H of a constant frequency at a specified position on the reference medium, and when adjusting the device, as shown in 11iU(&), , when the position of the head 2 to be adjusted is equal to the media position signal H,
The adjustment is performed by taking advantage of the fact that the gaze output is lower than the output of the head 1, that is, the head output that completely overlaps with the position signal H. For example, the output of head 1 is 10
0, if the output of the head 2 is 70, the position signal H
This means that there is a difference of 30%. As described above, the peak output changes depending on the positional characteristics of the head and the decrease in the magnetic output of the media. Depending on the method, it is necessary to set the head 1 to the state and detect the peak output. Looking at the reference media as a whole, as shown in Figure 1(b), at the position of head 7, the output is 100 because it overlaps with the position signal H of the reference media, but at the positions of heads 8 and 9, the output is I can't get the cuff to 0L. In other words, since the media that matches the head at each position is eccentric from the reference media, the amount of positional deviation on the circumference is different, and it is not possible to simply measure the deviation of the head at an arbitrary position. Only the amount of positional deviation at a specific point is detected. Therefore, even if the conventional method is used to adjust the positional deviation of the head, it is extremely troublesome and difficult to adjust with high precision.

OBJECTS OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the conventional technology by installing a reference medium into a floppy disk drive,
An object of the present invention is to provide a floppy disk position signal writing method that can detect the amount of positional deviation of a head simply by reading the position signal with the head.

In order to achieve the above object, the floppy disk position signal writing method of the present invention is such that when writing a reference position signal to a floppy disk, the head corona gap line is tilted with respect to the center of rotation. It is characterized by recording position signals.

Further, in this case, the recording device is characterized by having two different recording widths on the same track and recording two different frequency signals on the same track.

Examples of the invention 2 and 3 are diagrams showing the basic principle of the present invention.

In FIG. 3, l is the head that writes on the reference medium, and 2 is the head of the device to be adjusted.

When a position signal A is written by the head 1 at a specified position on the reference medium, the signal to be written at the end is 1. Write with only hi diagonal.

When a signal having an inclination angle is read out using a head without an inclination angle, this inclination angle will affect the readout signal.

Normally, in a station building where a signal written with a tilt angle is read and hung by a head without a tilt angle, as shown in Figure 2, -, the strength of magnetization is added from the upper end to the lower end surface of the rad, and the output is successively output. is obtained, so in any column 11 of the head, (→
Polar magnetization and (+) polarity ω are read alternately, and in the next column 12, (+) polarity and (-) polarity are read alternately, canceling each other out and producing nothing as one electrical signal. I can't read it.

Now, if the direction in which the end of the position signal A of the reference media machine in Fig. 2 is flooded is [direction], and the direction perpendicular to it is the y direction, then the wavelength λ is in the X direction and the tilt angle is λ in the y direction. The strength M of magnetization on the V body when recording by pressing is expressed by the following equation (1).

Nail 2″b ・・・・・(1) M-A
1yx(x +, y)λ When this body is read out by moving it in the .

Substituting AB/r-K into the above equation (2) leads to the following equation (3).
・C3,)b λ λ In the above equation (3), if b-λ, it becomes B-0, and if the read head 2 is misaligned by L as shown in FIG. 3, then the amount of misalignment is e Then, the maximum value Ep of the readout output is expressed by the following equation (4).

ETI-IKasin 7 I
``'''' (4) The fourth figure is a surface diagram of the maximum value of the readout output in Figure 3, and Figure 5 is a diagram F of the detailed operation theory of the fourth □□□.

As shown in Fig. 5<a), if the head overlaps with the position signal and there is no deviation, then π is calculated by cutting (3) because The output becomes E-0.

Next, if the amount of deviation between the head and the position signal is e;
Chiku 5 N (b) 5. ': As shown in L·2, the width of the position signal to be output becomes (r--e) instead of 8, and the X-direction component bl of the inclination becomes b'--λ instead of b. Therefore, instead of a in cutting allowance (3), use (a-), b
If -λ is replaced in each place, the cutting allowance becomes (4). This is represented by the curve in FIG.

Ep = l 2Kacos ;,, e l
, --, -(5) That is, if (a - e ) is substituted for a in machining allowance (3), and λ' is substituted for b, machining allowance (5) is obtained. This is shown in Figure 4 (b
) is represented by a curve.

Next, as shown in FIG. 7, when recording is performed alternately on the same track at two different frequencies, if the recording wavelength is λ - 100 λ' and b - λ, then the head is e.g. The output when the deviation is P1 is the output P1 of El:l of the curve in Fig. 4(,) and Ell of the curve of Fig. 4(b).
This is the value of the output P2 of l, and the amount of track deviation can be calculated from this output ratio. ' Fig. 6 is an explanatory diagram of a method for calculating the deviation amount e from P, , P, in Fig. 4 (&) (b).

The curve in Figure 4 (&) is the output o1 at angle 0 Figure 4 (b)
Since the curve has an output l at an angle of 0, the output ratio Ep is plotted on the vertical axis.
If we take λ/Epλ', we get a curve with output ratio 0 at angle 0 and output ratio 1 at angle 18o0 as shown in Figure 6. Therefore, the angle value for output ratio Epλ/Epλ' is shown in advance by a dotted line If this is determined, the head deviation amount e can be immediately obtained from the output ratio.

FIG. 8 is an explanatory diagram of a head position deviation detection method showing another embodiment of the present invention.

As for the position signal writing method, the standard frequency is 250KH.
An auxiliary signal F is recorded at a frequency slightly different from the reference frequency, for example, 255 KH2, in contact with the position signal consisting of the signal recorded at 2 and the signal E recorded at 125 KH2.

In this case, when the head is located at a position where the signal with the reference frequency of 250 KH overlaps, the readout output is 2
A signal with an amplitude d of 50 KH is obtained. On the contrary,
When the head 5 is located between the signal with a reference frequency of 25OKH and the auxiliary signal F with a frequency of 255KH,
As shown in FIG. 8(1)), a beat signal Z with a frequency of 5KH, which is the difference between them, is obtained. In this case, the output when the head 5 is positioned between the signal E of 125KH2 and the auxiliary signal F of 255KH is the peak ma! Since the amplitude C of the beat signal Z is calculated by the ratio of the amplitude C of the beat signal Z, the amount of deviation can be detected. In addition, if the head deviates downward from the reference position signal, no beat signal will be observed, as shown in Figure 4 (,).
The deviation l from the output of the value of P11P2 of the curve shown in (b)
can be detected.

Also, the reference frequency f. Adjacent to both sides of the position signal is a frequency f slightly different from the frequency f0.

10Δf0. There is also a method of writing an auxiliary signal using fo+Δf (however, Δf1+Δf2). With respect to the reference position signal D1 and the auxiliary signals F and J, if the head straddles D and F, a beat signal of frequency △f1 is generated;
and J, a beat signal of frequency Δf2 is observed. The amount of head deviation can be calculated using the period between the maximum amplitude value and the maximum φ value of the beat signal.

FIG. 9 is an explanatory diagram of a head deviation amount detection method showing still another embodiment of the present invention.

The signal H recorded at the reference frequency f0 is written with an inclination of the recording width a by a wavelength λ of °C1.

A signal Gt with a recording width of g by erasing a part of this signal
- When read, the output will be as shown in the following equation using the machining allowance (2).

In the above equation (6), Ego is also obtained at b−λ.

That is, the peak value is represented by the curve shown in FIG. 4(a).

Therefore, since the head displacement amount e is −h (e (h), Ep maintains a constant output, so that the head displacement position can be detected.

As described in detail, according to the present invention, after the reference medium is mounted on the device, the amount of deviation between the position signal on the head and the reference medium can be calculated as the readout output without applying any special operation to the head. Upstream detection is possible, and by detecting the phase of the readout waveform or the beat signal using the auxiliary signal,
It is also possible to detect the direction of positional deviation.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a conventional head position adjustment method using reference media, Figs. 2 and 3 are diagrams showing the basic principle of the present invention, and Fig. 4 is a relational curve of the maximum successive output value of Fig. 3. , 5th
The figure is a detailed operation explanation diagram of Figure 4, Figure 6 is P□ of Figure 4,
FIG. 7 is an explanatory diagram of a method for calculating the amount of deviation from P2, and FIG.
9 and 9 are explanatory diagrams showing other embodiments of the present invention and a method for detecting rad position deviation. 1-9: Head, A-H: Position signal, a: Signal width, e:
Amount of deviation. Patent Applicant Hitachi, Ltd. Representative Patent Attorney Usui 1) Room temperature Figure 1 Figure 2 Figure 112, Figure 3 Figure 4 E. Figure 7 Figure 8 Figure 9 Figure 5 Figure 6

Claims (3)

[Claims] (1) In the method of adjusting the head position by reading the reference position signal written on the 70-tube disc, when writing the reference position signal, the gap line of the head core is set to the center of rotation of the 70-tube disc. A floppy disk position signal writing method characterized by writing at an angle to the floppy disk. (2) The reference position signal has two different reference position signals on the same track.
2. A floppy disk position signal writing method according to claim 1, wherein the floppy disk position signal is recorded at two frequencies. (3) The reference position signal may be different on the same track.
2. A floppy disk position signal writing method according to claim 1, characterized in that the floppy disk has a recording width of 2.