JP3232862B2 - Adjustment device for magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus using an azimuth recording system such as a VTR.

[0002]

2. Description of the Related Art In recent years, magnetic recording / reproducing apparatuses utilizing magnetic recording have been widely used in the industry, and the azimuth recording method has been widely used to increase the recording density.

[0003] A conventional adjusting device for a magnetic recording / reproducing apparatus will be described below. 5 and 6 show an envelope waveform and a recording pattern on a tape in a conventional magnetic recording / reproducing apparatus adjusting device. First, a first adjusting example shown in FIG. 5 will be described. In FIG. 5, reference numerals 17 and 17 'denote an envelope indicating the head output, 18 denotes a protruding portion appearing in the envelope 17, and 19 denotes a drop portion of the envelope 17'. For normal track linearity adjustment, a track linearity adjustment master is used. The tracking volume is reduced in one direction, and while the envelope 17 or 17 ′ of the head output is observed, the projection 18 of the envelope or the depression 19 of the envelope is flattened. For example, the running system of the VTR is mechanically adjusted so as to be as follows.

Next, a second adjustment example will be described with reference to FIG. FIG. 6 shows a recording pattern (bitter pattern diagram) obtained by developing a magnetic recording tape on which a signal is recorded with, for example, a magnetic fluid or the like. In FIG. 6, reference numeral 20 denotes a magnetic recording tape; Is a recording track formed by recording a signal with a head, and 22 is a CTL signal.

In this adjusting device, the height of the CTL signal 22 up to the intersection (indicated by a dot) of each recording track is read with reference to the lower edge 23 of the magnetic recording tape 20.
The difference from the calculated height is taken, the difference is taken on the vertical axis, and each recording track is taken on the horizontal axis (lower edge to upper edge).
Is performed to determine the track linearity.

[0006]

However, in the above-mentioned first conventional adjustment example, as shown in FIG.
May not always be flat, but may be inclined. The envelope 25 may change slightly depending on the state of contact between the head and the tape, making it difficult to accurately check the track linearity. The error of the mechanical adjustment tends to occur. On the other hand, the second adjustment example has a problem that the development, measurement, and man-hours of the recording tape are required, and adjustment cannot be performed in real time.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide an adjusting device for a magnetic recording / reproducing apparatus capable of clearly detecting a track linearity error.

[0008]

In order to achieve this object, an adjusting device for a magnetic recording / reproducing apparatus according to the present invention converts at least a signal on a leading side by a time difference between a leading side and a lagging side of heads having different azimuth angles. A delay means for delaying, and an azimuth time difference detecting means for detecting a time difference between a synchronization signal of a real time signal and a delayed signal.

[0009]

According to the present invention, the adjusting device of the magnetic recording / reproducing apparatus detects the time difference between the real time signal and the delayed signal by the azimuth time difference detecting means, and detects the bending of the track linearity of the magnetic recording / reproducing apparatus. The time difference between
The absolute value or curve of the track linearity error from the tape format is clearly displayed in real time, enabling adjustment with a small track linearity error.

[0010]

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

FIG. 1 is a block diagram showing an adjusting device of a magnetic recording / reproducing apparatus according to a first embodiment of the present invention. FIG.
, 1 is a first head, 2 is a second head, and 3 is a head amplifier (H) that amplifies a reproduction signal of the first head 1.
A), 4 is a head amplifier (HA) for amplifying a reproduction signal of the second head 2, 5 is a synchronization signal separation circuit for separating a synchronization signal from a signal of HA 3, 6 is a synchronization for separating a synchronization signal from a signal of HA 4. The signal separation circuit 7 is a synchronization signal separation circuit 5
A delay circuit for delaying the separated sync signal by a time delayed from the leading side; an azimuth time difference detecting circuit for detecting a time lag between the sync signal from the delay circuit and the sync signal from the sync signal separating circuit; Is the azimuth time difference detection circuit 8
D / A for converting digital signals into analog signals
Displays the analog signal C.

In FIG. 1, a signal from the first head 1 is taken out only of a synchronization signal by a synchronization signal separation circuit 5, and is delayed by a delay circuit 7 by a time difference from a leading head to a lagging head. Although the details are omitted, the delay circuit is composed of a memory and outputs a signal with a delay corresponding to a time delay. On the other hand, the signal from the second head 2 is taken out of the synchronization signal only by the synchronization signal separation circuit 6 and inputted to the azimuth time difference detection circuit 8. In the azimuth time difference detection circuit 8, although the details of the time lag between the delayed synchronization signal from the first head 1 and the real-time synchronization signal from the second head 2 are omitted, the clock and the counter are used to detect the clock. Detected as pulse number. This pulse number is converted into an analog signal by the D / A 9.

As for the delay time, assuming that the magnetic head is disposed at an angle θH (rad), the delay time is dt, and the rotational speed is R.
(Hz), it can be expressed by dt = θH / (2π * R).

FIG. 2 shows a second embodiment of the present invention in which the signal delay is a 180-degree phase difference, and the head amplifiers HA3, HA4
, And the mixed signal is separated by a video signal separating circuit 5 into a synchronizing signal. One of the separated synchronizing signals is delayed by a 180 ° phase difference time through a delay circuit 7 and the other is synchronized in real time. Azimuth time difference detection circuit 8
And the two types of heads 1 and 2 having different azimuth directions
Are compared.

Next, the principle of detecting track bending by azimuth will be described. FIG. 3 is a conceptual diagram showing a track shift and a time shift of a two-channel signal of the adjusting device of the magnetic recording / reproducing apparatus. 12 is a first recording track, 1
3 is a second recording track, 10 and 11 are first and second heads capable of recording and reproduction, 10 'and 10 "are first heads 1
0, a head showing a state shifted in the track width direction of 0, 1
Reference numerals 1 'and 11 "denote heads that deviate in the track width direction of the second head 11, reference numeral 14 denotes a reproduction signal of the first head 10, reference numeral 15 denotes a reproduction signal of the second head 4, and reference numerals 15' and 1
5 "longitudinal displacement amount of the head is reproduced signal, W ₁ second head 11 of the second head 11 in a state shifted in the track width direction ', W ₂ is the second head 11" length of Direction deviation, t ₁ is the time deviation of the signal when the second head 11 is in the state of the head 11 ′, t ₂ is the time deviation of the signal when the _second head 11 is the head 11 ″, arrow X is the traveling direction of the head, ΔP is The shift amount θ in the track width direction for the heads 10 ″ and 11 ″ is an azimuth angle.

According to FIG. 3, when the first and second heads 10 and 11 come to the positions of the heads 10 'and 11' with respect to the first and second recording tracks 12 and 13, the reproduction signal 1
5 'generates a time lag t ₁ with respect to the reproduced signal 14, and when the head 10 ", 11" comes, the reproduced signal 15 "generates a time lag t ₂ with respect to the reproduced signal 14. 2
Recording tracks 12, 13 and the first and second heads 10,
Assuming that the relative speed with respect to Vt is Vt, the time lag t is t =
The deviation amount ΔP in the track width direction is represented by ΔP = Vt · t / (2 · tan θ). Therefore, to be able to detect with azimuth time difference,
One signal may be delayed so that the synchronization signals from the two heads 1 and 2 are substantially aligned over the entire track length.

FIG. 4 shows an oscilloscope screen for displaying the signal C extracted as described above. Reference numeral 16 denotes an oscilloscope screen on which the track linearity error curve q and the head switching signal r are both displayed. It is supposed to be. That is, the track linearity can be detected over the entire scanning period of the head.

As shown in FIG. 4, the oscilloscope screen 1
In FIG. 6, a clear track linearity error curve q is displayed in real time, and mechanical adjustment is performed so that the track linearity error is minimized. Further, in the adjusting device of the magnetic recording / reproducing apparatus of the present embodiment, the adjusting can be performed irrespective of the flatness of the envelope such as the head touch.

In the present invention, the delay amount is set to delay the time delay between the leading head and the lagging head.
Needless to say, since the heads arranged at 0 degrees are relative, one of them may be the leading side.

[0020]

As described above, the present invention delays at least the signal on the leading side by the time difference between the leading head and the lagging head, detects the time difference from the real-time signal, and uses the azimuth signal even in the single recording track format. Using the time difference detection device, a clear track linearity error can be read in real time, and further, the error of the master tape can be easily considered, and the practical effect is very large.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an adjusting device of a magnetic recording / reproducing device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an adjusting device of a magnetic recording / reproducing device according to a second embodiment of the present invention.

FIG. 3 is a conceptual diagram of an azimuth time difference track linearity detection method in the embodiment.

FIG. 4 is a plan view of an oscilloscope screen of the embodiment.

FIG. 5 is an envelope waveform chart for explaining a first adjustment example in a conventional magnetic recording / reproducing apparatus.

FIG. 6 is a pattern measurement diagram for explaining a second adjustment example in the conventional magnetic recording / reproducing apparatus.

FIG. 7 is a track linearity plot diagram in the measurement method in the second adjustment example in FIG. 6;

FIG. 8 is a waveform chart showing another example of an envelope waveform.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st head 2 2nd head 3, 4 Head amplifier 5, 6 Synchronization signal separation circuit 7 Delay circuit 8 Azimuth time difference detection circuit 9 D / A

Continuation of the front page (56) References JP-A-60-197902 (JP, A) JP-A-63-29301 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 5 / 00-5/024 604

Claims (1)

(57) [Claims] At least a first head and a second head are arranged so that adjacent recording tracks have different azimuth angles from each other, and are arranged with a predetermined phase in a rotational direction so as to record or reproduce a signal on a magnetic recording medium. A head drum having a head; delay means for delaying at least a signal from the preceding head by a time difference between the first head serving as the leading head and the second head serving as the lagging head; An adjusting device for a magnetic recording / reproducing apparatus, comprising: an azimuth time difference detecting means for detecting a time lag between a signal and a signal from the delay side head.