JPS61160821A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain the tracking control of a magnetic head in a reproduction mode by detecting the direction and the amount of variance of a magnetic head for reproduction from the track center from the output of a magnetic head for detection set at the side of the head for reproduction. CONSTITUTION:When magnetic heads 1a and 1b for position detection are deviated to the right side from the head scan direction 4, a part of the head 1a touches a guard band 60. Thus the reproduction output of the head 1a is reduced in response to the variance amount from the center of a recording track 3. In this case, however, the reproduction output of the head 1b has no change since the head 1b is set into the track 3. The reproduction outputs of both heads 1a and 1b are amplified by amplifiers 6 and 7 and then wave- detected by AM wave detectors 8 and 9. Then these outputs are supplied to a differential amplifier 10 and compared with each other. The direction and amount of variance from the track center are detected for a magnetic head 20 for reproduction. This detection signal is supplied to a controller 12 for reproduction head position via an amplifier 11. Thus the tracking control is possible with magnetic heads in a reproduction mode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording/reproducing apparatus, and more particularly to a magnetic recording/reproducing apparatus capable of controlling tracking of a magnetic head during reproduction.

[Prior Art] FIG. 5 is a diagram showing the positional relationship between a magnetic head and a recording track of a magnetic tape during reproduction in a conventional helical scanning type perpendicular magnetic recording and reproducing apparatus (hereinafter abbreviated as vertical VTR). In the figure, a magnetic head is provided on a rotating drum (not shown) so as to be exposed from its circumferential surface, and the magnetic head is rotated by the rotation of the rotating drum.

Further, the magnetic tape 5 is run in the direction of arrow 70 in the figure,
A magnetic head is brought into contact with the magnetic tape 5.

When recording information signals, the rotating drum rotates and the magnetic tape runs, and the magnetic head moves the magnetic tape 5 in the direction of arrow 4 in the figure.
The information signal is recorded on the recording track 3 by helical scanning in the direction. At this time, in order to avoid crosstalk, guard bands (no-signal recording portions) 60 with very small widths are provided on both sides of each recording track 3. When reproducing an information signal, the recording track 3 of the magnetic tape 5 is read by the reproducing magnetic head 2.
The change in magnetic flux of the recorded information signal is detected by helical scanning in the four directions of arrows, and this is electromagnetically converted to obtain a reproduced information signal.

[Problems to be Solved by the Invention] In conventional vertical VTRs, tracking control of the magnetic head is not performed during playback, so if the playback magnetic head 2 deviates from the recording track 3, the playback signal output decreases. There have been problems such as a decrease in the S/N ratio of the reproduced signal due to glue O stalk from adjacent tracks.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a VTR capable of controlling tracking of a magnetic head during reproduction.

Means for Solving Problem E] The VTR according to the present invention is provided with a detection magnetic head for detecting an information signal recorded from a track separately on the side of the reproduction magnetic head, and detects information signals from the output of the detection magnetic head. The direction and amount of deviation of the magnetic reproduction head from the center of the track is detected, and in response to the detected direction and amount of deviation, the magnetic reproduction head is controlled to align with the center of the track. .

[Function] In this invention, when the reproducing magnetic head deviates from the center of the track, the detecting magnetic head falls on the insensitive band and the output of the detecting magnetic head decreases, and by detecting this decrease, the reproducing The direction and amount of deviation of the magnetic head from the center of the track are detected.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

In the description of this embodiment, the description of parts that overlap with the description of the conventional technology will be omitted as appropriate.

FIG. 1 is a block diagram of a tracking control section of a reproducing magnetic head in a vertical VTR which is an embodiment of the present invention. First, the configuration of this tracking control section will be explained. In the figure, the position detection magnetic head 1a is head amplified! 16. Differential amplification si via AM detector 8
The position detection magnetic head 1b is connected to the head amplifier 7.o. It is connected to a differential amplifier 10 via an AM detector 9.

The differential amplifier 10 is connected to a read head position control device 12 via an amplifier 11.

FIG. 2 is a diagram showing a tracking state of a reproducing magnetic head in a vertical VTR which is an embodiment of the present invention. On both sides of each recording track 3 of the magnetic tape 5, guard bands 60 (non-signal recording portions) with a very small width are provided in order to avoid crosstalk. In front of the reproducing magnetic head 20, which is narrower than the width of the recording track 3, a pair of position detecting magnetic heads 1a and 1b are provided fixedly to this magnetic head. A shows a state in which the reproducing magnetic head 20 is tracking the recording track 3 normally.

B shows a state in which the reproducing magnetic head 20 is shifted to the right from the center of the recording track 3 with respect to the head scanning direction 4 in the figure, and a part of the proverb detection magnetic head 1a is covered with the guard band 60. , a magnetic head 1b for position detection is placed in the recording track 3.

Next, this tracking control operation will be explained. Now, the position detection magnetic heads 1a and 1b are in the head scanning direction 4.
If it deviates to the right (as indicated by arrow B in the figure),
A part of the magnetic head for position detection 1a is covered by the guard band 60, and the reproduction output of the magnetic head for position detection 1a decreases by an amount corresponding to the amount of deviation from the center of the recording track 3. Since the head 1b is within the recording track 3, its reproduction output does not change. The reproduction outputs of the position detecting magnetic heads 1a and 1b are each amplified by a head amplifier 6.7 and detected by an AM detector 8.9, and then
It is input to the differential amplifier 10.

The differential amplifier 10 detects the direction and amount of deviation of the position detecting magnetic heads 1a and 1b from the center of the recording track 3 by comparing the reproduction outputs from the position detecting magnetic heads 1a and 1b, and uses this detection signal. After being amplified by the amplifier 11, the signal is input to the reproduction head position control device f12 (for example, a device using a bimorph). Playback head position control device 1
! 12 controls the position of the reproducing magnetic head 20 so as to align it with the center of the recording track 3 according to the direction and amount of the detected deviation.

FIG. 3 is a block diagram of a tracking control section of a reproducing magnetic head in a vertical VTR which is another embodiment of the present invention. First, the configuration of this tracking control section will be explained. Incidentally, the position detection magnetic head 1 includes a head amplifier 6. It is connected to a sample and hold circuit 13 and a sample and hold circuit 14 via an AM detector 8 . Further, one clock signal generation circuit is connected to a sample and hold circuit 13, and one clock signal generation circuit is connected to a τ delay circuit 20.
It is connected to the sample and hold circuit 14 via. Sample and hold circuit 13 and sample and hold circuit 14
is connected to the comparator 15, and the comparator 15 is
Counter 16. D/'A converter 17. The playback head position I is passed through a low-pass filter (hereinafter abbreviated as LPF) 18.
filI'm device 12 .

FIG. 4 is a diagram showing a tracking state of a reproducing magnetic head in a vertical VTR which is another embodiment of the present invention. In front of the reproducing magnetic head 20, a single position detecting magnetic head 1 having the same width as the recording track 3 is provided fixedly to this magnetic head. , A shows a state in which the reproducing magnetic head 20 is tracking the recording track 3 normally. B shows a state in which the reproducing magnetic head 20 is shifted to the right from the center of the recording track 3 with respect to the head scanning direction 4 in the figure, and a part of the position detecting magnetic head 1 is covered by the guard band 60. There is.

Next, this tracking control operation will be explained. Now, if the position detection magnetic head 1 is shifted to the right with respect to the head scanning direction 4 (the state indicated by arrow B in the figure), a part of the position detection magnetic head 1 will be caught on the guard band 60, and the position detection The reproduction output of the magnetic head 1 is reduced by an amount corresponding to the amount of deviation from the center of the recording track 3. The reproduced output of the position detecting magnetic head 1 is amplified by an amplifier 6 and converted into an AM
After being detected by the detector B8, the signal is input to the sample and hold circuit 13 and the sample and hold circuit 14. The clock pulse from the clock signal generation circuit 19 is input to the sample hold circuit 13 as it is, and is also input to the sample hold circuit 14 after being delayed by a minute time τ in the τ delay circuit 20 . The sample hold circuit 13 is
The output of the AM detector 8 is sampled only while the clock pulse is ON, and the sample hold circuit 14 has a minute time τ than the sampling of the sample hold circuit 13.
The AM detector 8 output is sampled with a delay of . A comparator 15 compares the output of the sample and hold circuit 13 and the output of the sample and hold circuit 14. At this time, the sample and hold circuit 13 output is the sample and hold circuit 14.
If it is larger than the output, the counter 16 outputs a (+) signal, and in the opposite case, the counter 16 outputs a (-) signal. By converting these signals from the counter 16 into analogs with the D/A converter 17 and passing them through the LPF 18, the direction and amount of deviation of the position detecting magnetic head 1 from the center of the recording track 3 can be detected. This detection signal is input to the reproducing head position control device 12, and the position of the reproducing magnetic head 20 is carried out.

Note that if the signal sampled by the sampling and holding circuit 13 and the signal sampled by the sampling and holding circuit 14 are equal at startup, the reproducing magnetic head is shifted from the recording track 3 in either direction, and for example, the counter 16 is always set to (+ ) By outputting a signal, it is possible to determine in which direction the position detection magnetic head 1 is shifted from the center of the recording track 3.

Furthermore, by using the position detection magnetic head 1 as a recording magnetic head when recording information signals, the width of the recording track 3 can be made to accurately match the width of the position detection magnetic head 1, which improves accuracy. This enables high position detection.

In addition, in the above embodiment, the vertical V when there is a guard band
Although tracking control in a TR has been described, even in tracking control in an in-plane horizontal VTR using a tilted azimuth method without a guard band, the output decreases when the position detection magnetic head deviates from the recording track. It is possible to control the position of the reproducing magnetic head.

[Effects of the Invention] As described above, according to the present invention, a detection magnetic head is separately provided on the side of the reproduction magnetic head, and the deviation from the track center of the reproduction magnetic head is determined from the output of the detection magnetic head. The direction and amount of the deviation are detected, and in response to the direction and amount of the detected deviation, the reproducing magnetic head is controlled to align with the center of the track, making it possible to track the magnetic head w4m during reproducing, making it stable. It is possible to obtain a playback output that is

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a tracking control section of a reproducing magnetic head in a vertical VTR which is an embodiment of the present invention. FIG. 2 is a diagram showing a tracking state of a reproducing magnetic head in a vertical VTR which is an embodiment of the present invention. FIG. 3 is a block diagram of a tracking control section of a reproducing magnetic head in a vertical VTR which is another embodiment of the present invention. FIG. 4 is a diagram showing a tracking state of a reproducing magnetic head in a vertical VTR which is another embodiment of the present invention. Figure 5 shows a conventional helical scanning vertical VT.
FIG. 6 is a diagram showing the positional relationship between the magnetic head and the recording track of the magnetic tape during reproduction in R. In the figure, 1.1a and 1b are magnetic heads for position detection;
2.20 is a magnetic head for reproduction, 3 is a recording track, 5 is a magnetic tape, 6.7 is a head amplifier, 8 and 9 are AM detectors, 10 is a differential amplifier, 11 is an amplifier, 12 is a reproduction head position control il device, 13.14 is a sample hold circuit, 15 is a comparator, 16 is a counter, 17 is a D/A
Converter, 18 is a low-pass filter, 19 is a clock signal generation circuit, 20 is a τ delay circuit, and 60 is a guard band. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (3)

[Claims] (1) In a magnetic recording/reproducing apparatus that records an information signal on each track separated by a dead band of a magnetic recording medium using a magnetic head, and reproduces the information signal recorded from each track, the information signal is a detection magnetic head that is provided on a side of the magnetic head for reproducing and detects the recorded information signal from each track; and a detection magnetic head that reproduces the information signal from the output of the detection magnetic head. a detection means for detecting the direction and amount of deviation from the center of the track; and a control means for controlling the magnetic head for reproducing the information signal to align with the center of each track in response to the output of the detection means. A magnetic recording and reproducing device equipped with (2) The magnetic recording and reproducing apparatus according to claim 1, wherein the detection magnetic head comprises first and second detection magnetic heads. (3) The magnetic recording/reproducing apparatus according to claim 1, wherein the detection magnetic head is used as the magnetic head for recording the information signal on each of the tracks.