JPS589500B2 - It's hard to do anything. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head position control device for locating a magnetic head on a signal track on a magnetic recording medium.

In a magnetic recording/reproducing device using a rotating magnetic disk,
When recording is performed concentrically with a narrow track pitch,
Since it was difficult to correctly position the magnetic head on a desired track during reproduction, conventionally two control signal heads 2 were used to extract the control signal, as shown in FIG.
' and 3' are provided to span the signal track 4' and the inter-track spacing guard 5', respectively, and the signal head 1
' and is integrally constructed with the head holding mechanism.

When the signal head 1' is correctly placed on the desired signal track 4', the control signal heads 2' and 3'
By controlling the head position control mechanism so that the difference signal between the signals reproduced from each signal track 4' becomes zero and driving the head holding mechanism, the signal head 1' is correctly positioned on the desired signal track. It was placed.

In this way, interchangeability with magnetic media recorded in other rotating magnetic disk devices can be facilitated, and
Even if the magnetic medium expands or contracts due to temperature changes, the magnetic head (signal head 1') can be correctly placed on the desired signal track. Signal head 2'
pcs required.

Furthermore, since it is necessary to provide the inter-track spacing guard 5' with a width that is approximately the same as or greater than the width of the signal track 4', it is difficult to increase the recording capacity of the magnetic medium by increasing the track density. There were drawbacks.

This invention was made to eliminate the above-mentioned conventional drawbacks, and the present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional technology. By recording position control signals, the magnetic recording capacity can be increased, and at the same time, only one control signal head is required, thereby providing a magnetic head position control device that can be manufactured at low cost.

Next, an embodiment of the magnetic head position control device of the present invention will be described with reference to the drawings. FIG. 2 is a block diagram showing the configuration of one embodiment.

1 in FIG. 2 is a rotating magnetic disk that rotates in the N direction, and a signal head 2 and a control signal head 3 are mounted on the rotating magnetic disk 1 in a head holding mechanism 5 that moves in the radial direction of the rotating magnetic disk. held together and facing each other.

Further, the signal track 4a is formed concentrically by the signal head 2, and the control signal track 4b is formed concentrically by the control signal head 3.

The head holding mechanism 5 is positioned by a head position control mechanism 6.

The arrangement of the signal head 2 and the control signal head 3 in the head holding mechanism 5 is shown in FIG. 4a, and N in FIG. 4a is the same as in FIG. The rotation direction of the rotating magnetic disk 10 is shown, and the control signal head 3 is arranged ahead of the signal head 2 with respect to this rotation direction N.

Here, the dotted line indicates the head gap between the signal head 2 and the control signal head 3, W is the track width of the signal head 2, and the track width of the control signal head 3 is set to 2W. In the example, the ratio of signal tracks to control signal tracks would be 2:1.

Next, track formation during recording will be described. An FM signal obtained by converting a composite video signal into an FM signal is recorded on the signal track 4a by the signal head 2 as an information signal.

Furthermore, two low-frequency sine wave signals that do not overlap in frequency with the information signal on the signal track 4a are alternately recorded as position control signals on the control signal track 4b.

First, when the signal head 2 records information on odd-numbered signal tracks, a sine wave signal with a frequency of F1 is applied to the control signal head 3, and the control signal head 3 precedes the signal head 2. Therefore, the control signal head 3 records a sine wave signal of frequency F1 with a track width of approximately 2W, and then the signal head 2 records an information signal overlappingly on the track with a width of approximately W. , the signal of the approximately 2W track is updated over approximately the track width W.

Therefore, the signal track 4a of track width W and the frequency F
Two tracks each having a track width of W/2 are formed on which one sine wave signal is recorded.

In FIG. 4b, 3a, 3b, 3c indicate the positions where the control signal head 3 is in contact with the rotating magnetic disk 1,
2a, 2b, and 2c indicate the positions where the signal head 2 is in contact with the rotating magnetic disk 1. In the above recording operation, the control signal head 3 is at the position 3a, and the signal head 2 is at the position 2.
This is done when it is in position a.

When recording the next information signal, it is recorded on the even numbered signal track, and the head holding mechanism 5 is sent in the direction Q in the radial direction of the rotating magnetic disk 1 at a pitch P=+W, so that the control signal head 3 is 3b, and the signal head 2 is brought into contact with the rotating magnetic disk 1 at a position 2b.

In addition, in FIG. 4b, the positions 3b and 2b are shifted parallel to the right side from their actual positions in order to explain the operation in an easy-to-understand manner.

The actual position is indicated by a dotted line.

When an information signal is recorded on an even-numbered signal track, a sine wave signal having a frequency of F2 is applied to the control signal head 3, and the control signal head 3 performs recording in advance of the signal head 2. Therefore, the signal head 2 forms a track with a track width of 2W on which a sine wave of frequency F2 is recorded.

By this recording operation, the control signal track having a track width W/201 is overwritten and the recorded signal, that is, a sine wave signal of frequency F1 is updated to a sine wave signal of frequency F2.

Further, the information signal is recorded by the signal head 2 with a track width W on the track with the track width 2W,
Even numbered signal tracks of track width W are formed.

Therefore, an even numbered signal track in which a sine wave signal of frequency F2 with a track width of 1/2 W is recorded is formed in the interval between the odd numbered signal track and the even numbered track.

When recording the following information, select the odd numbered signal track. Since the head holding mechanism 5 is similarly sent in the radial direction of the rotating magnetic disk 10 in the direction of Q at pitch P=3/4W, the control signal head 3 is at the position 3c, and the signal head 2 is at the position 3c. They are brought into contact with the rotating magnetic disk 1 at positions 2c, respectively.

The position of each head in this case is also compared to the actual position, and furthermore,
Shown parallel to the right.

When an information signal is recorded on an odd-numbered signal track, a sine wave signal with a frequency F is applied to the control signal head 3, and thereafter, a sine wave signal with a frequency F2 of the track width - VVJ is recorded in the same procedure. The control signal tracks that have been recorded are overlaid and recorded, and a sine wave signal with a track width of +W and a frequency F1 is recorded between the odd numbered signal track of track width W, the above even numbered signal track, and this newly recorded odd numbered track. Odd-numbered control signal tracks are formed.

Similarly, when recording information signals, the head holding mechanism 5 is sent successively in the radial direction of the rotating magnetic disk 10 at a pitch of 3/4 W, so that odd and even numbers of the track width W are recorded on the rotating magnetic disk 1. Signal track 4a, and odd and even numbered tracks with a track width of 1/2 W, in which sine wave signals of frequencies F1 and F2, which do not overlap in frequency with the information signal recorded on the signal track 4a, are recorded alternately as position control signals. A control signal track 4b is formed.

At the time of reproduction, as shown in FIG. Placed on the signal track with coarse precision.

The control signal head 3 is constructed integrally with the signal head 2, and is arranged so as to straddle the signal track 4a and the odd-numbered and even-numbered control signal tracks adjacent on both sides of this signal track, so that two positional controls can be achieved. Regenerate the signal and information signal simultaneously.

A precise position signal is obtained by taking the difference between the information signal and the two separated position control signals.

This precise position signal, that is, the position error signal, controls the head position control mechanism 6 to place the signal head 2 at the correct position on a desired track.

Hereinafter, this precise position signal will be referred to as a position error signal.

Now, in order to correctly locate the signal head 2 on the desired signal track 4a, the position error signal must indicate the amount and direction of deviation of the signal head 2 from the signal track.

The signal head 2 and the control signal head 3 are set at positions such that the position error signal becomes zero when the signal head 2 is correctly placed on the desired signal track 4a, and these heads are It is provided integrally with the mechanism 5.

The positional relationship between the signal head 2 and the control signal head 3 is shown in FIG. 4a, as described above.

Next, the fifth section will explain the principle of extracting a position error signal applied to the magnetic head position control device according to the present invention.
This will be explained with reference to the figures.

Since the track width of the signal track 4a is W, the track width of the control signal track 4b is W/2, and the track width of the control signal head 3 is 2W, the control signal head 3 and the signal head 2 are now in the fifth position. Assume that the signal track and the control signal track are in contact with each other at the position shown in FIG. b.

In this case, the control signal head 3 reproduces a signal having a spectrum as shown in FIG.

In FIG. 3, a1 and a2 are FM signals reproduced from the odd-numbered signal track and the even-numbered signal track 4a, respectively, and they overlap within the band.

Further, b and C indicate position control signals having frequencies F1 and F2 reproduced from the odd-numbered and even-numbered control signal tracks 4b, respectively.

The position control signal from the reproduction output of the control signal head 3 is separated from the reproduction FM signal by band amplifiers having resonance frequencies F1 and F2, respectively.

The reproduction output of these position control signals is determined by the tangent product of the control head 3 and the control signal track 4b, and the ratio of the reproduction output is determined by the ratio of the tangent products.

Fig. 5 is a head arrangement diagram when the signal head 2 is arranged on an even numbered signal track, and Fig. 5a is a head arrangement diagram of the signal head 2.
is correctly placed on the even-numbered signal track 4a.

In both figures a and b of FIG. 5, F1, F2
indicate the frequencies of the position control signals recorded in the odd-numbered and even-numbered control signal tracks, respectively.

Since the control signal head 3 is in complete contact with the even-numbered signal track 4a and the odd-numbered and even-numbered control signal tracks 4b adjacent to both sides of the even-numbered signal track 4a, the control signal head 3 and the odd-numbered and even-numbered control signal tracks 4b are adjacent to each other. The area of contact with the number control signal track is equal.

Therefore, the reproduction outputs of the position control signals of frequencies F1 and F2 reproduced from the control signal track 4b are equal, and the difference signal of the position control signals becomes zero.

Now, as shown in FIG. 5b, when the signal head 2 deviates from the normal position by Δd in the direction of the arrow, the control signal head 3 also deviates by Δd in the direction of the arrow.
Compared to the case of the above normal position, the contact area between the control signal head 3 and the odd-numbered control signal track does not change, and the contact area with the even-numbered control signal track decreases. The output of the position control signal from the even-numbered signal track does not change, and the output of the position control signal from the even-numbered signal track decreases in accordance with the deviation amount Δd.

When the signal head 2 is further displaced in the direction of the arrow as shown in FIG. becomes zero, so the output of the position control signal from the even-numbered control signal track becomes zero.

Furthermore, when the signal head 2 deviates from the normal position by Δd in the direction opposite to that shown in FIG. △d
The output of the position control signal from the even-numbered control signal track remains unchanged.

Furthermore, when the signal head 2 is displaced in the same direction as the above direction, the output of the position control signal from the even-numbered control signal track remains unchanged, and the pair of the control signal head 3 and the odd-numbered control signal track is Since the contact area becomes zero, the output of the position control signal from the odd-numbered control signal track becomes zero.

Therefore, by taking the difference between the position control signals of frequencies F1 and F2 reproduced by the control signal head 3, signals with equal absolute values and opposite polarities can be obtained depending on the deflection and direction of the signal head 2. I understand.

By controlling the head position control mechanism 6 and driving the head holding mechanism 5 so that the magnitude of the difference signal between the position control signals, that is, the position error signal, becomes zero, the signal head 2
can be placed at the correct position on the signal track, in this case on the even numbered signal track 4a.

Next, referring to FIG. 2, the structure and operation of the apparatus of the present invention will be described in detail. The coarse position signal from the track address register 7 operates the head position control mechanism 6, and the signal head 2 is placed on a desired signal track with rough precision, and the signal head 2 and the control signal head 3 simultaneously reproduce the information signal and the position control signal from the signal track 4a and the control signal track 4b, respectively.

The output signal of the signal head 2 is input to a reproduction amplifier 17 and amplified.

The output signal of the control signal head 3 is transmitted to the tuned amplifier 8.
and 9, and these tuned amplifiers 8 and 9 are tuned to their respective specific frequencies.

That is, the tuned amplifier 8 is tuned to the frequency F1, and the tuned amplifier 9 is tuned to the frequency F2 to detect the position control signal.

The output side of the tuned amplifier 8 is connected to gate circuits 10 and 11, and the output side of the gate circuit 10 is connected to one input side of the differential amplifier 7 via an envelope detection circuit 14 via an amplifier 12. has been done.

Similarly, the output side of the amplifier 9 is connected to the gate circuit 10,
11, and the output side of the gate circuit 11 is connected to the differential amplifier 1 via the amplifier 13 and the envelope detection circuit 15.
6 is connected to the other input side of 6.

The position control signals detected by the tuned amplifiers 8 and 9 are passed through a pair of gate circuits 10 and 11 and amplifiers 12 and 13 from the tuned amplifiers 8 and 9, respectively, to an envelope detection circuit 1.
Sent to 4.15.

The position control signal whose envelope has been detected by the envelope detection circuits 14 and 15 is input to the differential amplifier 16 so that the output signal of the envelope detection circuit 15 becomes a negative polarity input. The difference signal is amplified.

The differential amplifier 16 provides a precise position signal corresponding to the deviation of the signal head 2 from its normal position, that is, a position error signal.

At this time, the gate circuits 10 and 11 are opened and closed so as to pass or block the signals from the tuned amplifiers 8 and 9.

When the signal head 2 is correctly arranged on the signal track 4a, the control signal head 3 is in contact with the odd number control, depending on whether it is arranged on an odd numbered signal track or when it is arranged on an even numbered signal track. Since the relative positional relationship between the signal track and the even-numbered signal track is opposite,
In order to provide the proper polarity to the position error signal obtained at the output of the differential amplifier 16, the connections of the tuning amplifier and gate circuit can be reversed.

That is, when the signal head 2 is correctly placed on an odd-numbered signal track, the tuned amplifier 8 is connected to the gate circuit 11,
Tuned amplifier 9 is connected to gate circuit 10 .

On the other hand, when correctly disposed on an even numbered signal track, the tuned amplifier 8 is connected to the gate circuit 10 and the tuned amplifier 9 is connected to the gate circuit 11.

This reversal of the connection is effected by a signal from the track address register 7.

Whether the address of the desired signal track is an odd number or an even number is determined by the presence or absence of a binary value "1" in the lowest digit of the track address register 7.

According to the result of this determination, the track address register 7 sends a gate signal to the gate circuits 10 and 11 to instruct the appropriate gate, so that the differential amplifier 16 always receives a position error signal of the correct polarity.

By supplying this position error signal to the head position control mechanism 6, the head position control mechanism 6 drives the head holding mechanism 5 according to the polarity and amplitude of the position error signal, and moves the signal head 2 to a desired signal track. 4a in the correct position.

Therefore, the output of the reproduction amplifier 17 includes the information signal recorded on the signal track 4a corresponding to the signal head 2 which is placed at the correct position by the head position control mechanism 6, that is, the composite video signal, into an FM signal. A converted FM signal is obtained.

On the other hand, 17 is a reproducing amplifier whose input side is connected to the signal head 2, and whose output side is connected to an output terminal 20 via a limiter 18 and an FM demodulator 19.

The output signal of the reproduction amplifier 17 has amplitude fluctuations removed by a limiter 18, and then FM demodulated by an FM demodulator 19, and a composite video signal is reproduced at an output terminal 20.

In the above explanation, the signal track and control signal track were formed by overlapping recording, but an erasing head with the same track width as the signal head is provided in advance of the signal head, and the signal track and control signal track are erased. Needless to say, the same effect can be obtained by providing a track.

As detailed above, according to the present invention, the signal head and the control signal head are integrally provided in the head holding mechanism, and the control signal track is provided by overlapping recording between the signal tracks, and the odd number Two signals of different frequencies that do not overlap in frequency with the information signal recorded on the signal track are alternately recorded on the number control signal track and the even number control signal track as position control signals, and the position is controlled by the control signal head. By extracting the signal and controlling the position of the signal head so as to make the difference signal between the position control signals zero, information on the desired signal track can be reproduced, eliminating the drawbacks of conventional methods. Since the control signal track is removed and the control signal track is provided in the guard portion between the signal tracks, the recording capacity of the magnetic medium is not reduced.

Furthermore, in the conventional method, the interval between signal tracks had to be at least equal to or larger than the signal track width, but according to the present invention, the interval between signal tracks, that is, the width of the control signal track is larger than the width of the signal track. Since it can be made smaller, the recording capacity of the magnetic medium can be increased, and since it requires one less head for control signals than the conventional system, it can be made at low cost.

Furthermore, even if the rotating magnetic disk recorded in other rotating magnetic disk devices expands and contracts due to temperature and humidity, or even if the rotating magnetic disk is mounted eccentrically on the rotating shaft and sways, the signal head can still receive the desired signal. Since it can be placed at the correct position on the track, it has the effect of making it easier to replace the rotating magnetic disk.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between a magnetic head and a track in a conventional magnetic head position control device, FIG. 2 is a block diagram showing the configuration of an embodiment of the magnetic head position control device of the present invention, and FIG. The figure is a frequency spectrum diagram of the reproduction signal of the control signal head in the position control device for the above magnetic head, and Fig. 4a shows the signal head and the control signal head in the head holding mechanism used in the position control device for the above magnetic head. FIG. 4b is a diagram for explaining the operation during recording of the signal track and control signal track in the position control device for the magnetic head, and FIG. 5a is the position control device for the magnetic head. FIG. 5b is a diagram showing a state in which the magnetic head is placed at a normal position on a signal track, and FIG. DESCRIPTION OF SYMBOLS 1... Rotating magnetic disk, 2... Signal head, 3... Control signal head, 4a...
...Signal track, 4b...Control signal track, 5...Head holding mechanism, 6...
Head position control mechanism, 7... Track address register, 8, 9... Tuning amplifier, 10, 11...
...Gate circuit, 14,15...Envelope detection circuit, 16...Differential amplifier, 18...
・Limitsuta, 19...FM demodulator, 20...
...Output terminal. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A magnetic recording/reproducing head and a control signal head which precedes the magnetic recording/reproducing head by a minute distance in the circumferential recording direction of a rotating magnetic disk and have a wider track width than the magnetic recording/reproducing head are integrated, By sequentially moving the rotating magnetic disk in the radial direction at a nearly constant feed pitch narrower than the track width of the control signal head,
A signal track in which information is recorded at approximately constant intervals in the radial direction of the magnetic disk, and two signals having different frequencies that do not overlap in frequency with the information recorded on this signal track are located between the signal tracks. The magnetic recording/reproducing head is provided with control signal tracks which are alternately recorded in the interval portions, and the magnetic recording/reproducing head is provided so as to straddle the signal track on which the magnetic recording/reproducing head is provided during reproduction, and the control signal tracks adjacent on both sides of the signal track. The position of the magnetic recording/reproducing head is controlled to move in the radial direction of the rotating magnetic disk using a difference signal between two signals reproduced by a control signal head integrally formed with the head as a control signal. A position control device for a magnetic head.