JPH07129934A - Magnetic head azimuth angle detection method, azimuth angle detection medium, azimuth angle detection device, and azimuth angle adjustment device - Google Patents

Abstract

(57) [Summary] [Purpose] To enable accurate adjustment of the azimuth angle of the magnetic head without being affected by the tape speed and other factors. [Construction] Two azimuth angle detection signal tracks 15 and 16 and a reference clock recording track 17 are formed on the recording surface of a test tape 5. The tape running reference surface 5 of the test tape 5 is provided on the azimuth angle detection signal tracks 15 and 16.
Magnetization transition points 21 and 31 are provided on the vertical line of a, and the magnetization transition points 41 to 31 are formed on the reference clock recording track 17 at a pitch sufficiently smaller than the formation pitch of the magnetization transition points 21 and 31.
44, 41'-44 'are provided. In the read signal of the magnetic head, the number of read signals at the magnetization transition points 41 to 44 between the read signal at the magnetization transition point 21 and the read signal at the magnetization transition point 31 is counted, and from this count result, the azimuth transition angle θ of the magnetic head is counted. Ask for.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an azimuth angle detecting method, an azimuth angle detecting medium, an azimuth angle detecting device used for adjusting an azimuth angle of a magnetic head during a magnetic head assembly process in a magnetic recording / reproducing apparatus. The present invention relates to an azimuth angle adjusting device.

[0002]

2. Description of the Related Art An azimuth angle of a head gap in a magnetic head such as a multi-track thin film magnetic head causes an azimuth loss and a signal time difference between tracks, and prevents deterioration of an SN ratio of a magnetic recording / reproducing apparatus. However, high azimuth angle accuracy is required to ensure compatibility between devices. Therefore, during the mounting process of the magnetic head in the magnetic recording / reproducing apparatus, the azimuth angle is detected and adjusted using a test tape or a tool microscope. For example, in the process of attaching a magnetic head to a tape recorder of an analog compact cassette, when detecting an azimuth angle using a test tape, the analog signal recorded on the full width of the test tape is reproduced by two reproducing heads, The azimuth angle was detected from the phase difference of the reproduction output, and adjustment was made so that it would be an appropriate value.

Digital compact cassette (hereinafter DC
If the magnetic head used in C) has an analog dedicated track, the azimuth angle can be detected using the above-described test tape on which an analog signal is recorded.

[0004]

However, in the conventional method using the test tape recording the analog signal, the detection accuracy of the azimuth angle is lowered due to the distortion of the reproduction signal and the deviation of the tape speed, and the magnetic head is mounted accurately. There was a problem I couldn't do. Further, in the conventional method, since the phase difference between tracks is output as an analog amount, in order to control the adjustment of the mounting angle of the magnetic head using a microcomputer or the like, a digital amount is converted by a D / A converter or the like. There is a problem that the circuit configuration is complicated because it needs to be converted. Furthermore, in the case of a thin film magnetic head having only digital tracks, particularly a magnetoresistive (MR) head, the linearity of the reproduced signal is poor, and the azimuth angle is adjusted using a test tape on which an analog signal is recorded. If these problems are exacerbated.

An object of the present invention is to run a detection medium on which a reference signal is recorded together with a plurality of detection signals and detect the azimuth angle of the magnetic head based on the number of read reference signals among the plurality of detection signals. , The azimuth angle can be accurately detected without being affected by the distortion of the reproduction signal and the tape speed deviation, and even if the microcomputer controls the mounting angle adjustment mechanism of the magnetic head, etc. An object of the present invention is to provide a method for detecting an azimuth angle of a magnetic head, a medium for detecting an azimuth angle, an azimuth angle detecting device, and an azimuth angle adjusting device that do not complicate the configuration.

[0006]

According to the azimuth angle detecting method of the present invention, a plurality of detection signals having a predetermined frequency and a reference signal having a frequency higher than the predetermined frequency of the detection signals are recorded on a detection medium, A signal is read from the detection medium through the magnetic head, and the number of reference signal reads between the time when one detection signal is read and the next detection signal is read is counted, and the azimuth angle of the magnetic head is calculated from this count value. Is characterized by.

The medium for detecting an azimuth angle of a magnetic head according to a second aspect is formed at a plurality of positions on the azimuth angle of a recording pattern on a magnetic recording medium, and each has a magnetic transition point at equal intervals in the traveling direction. A plurality of detection signal tracks and a reference signal track having magnetization transition points formed at intervals smaller than the magnetization transition points of the detection signal tracks are provided.

In the azimuth angle detecting device for a magnetic head according to a third aspect of the present invention, reference signal counting means for counting the reference signal read from the detection medium by the magnetic head, and the next detection after the magnetic head reads the detection signal. And an azimuth angle calculating means for obtaining the azimuth angle of the magnetic head from the counting result of the reference signal counting means until the signal is read.

An azimuth angle adjusting device according to a fourth aspect comprises the azimuth angle detecting device for a magnetic head according to the third aspect, and adjusts a mounting angle of the magnetic head by using a calculation result of the azimuth angle calculating means as an input. The feature is that an azimuth angle adjusting mechanism is provided.

[0010]

According to the first aspect of the invention, the number of read reference signals is counted from the time when the magnetic head reads one detection signal to the time when the other detection signal is read. The read number of this reference signal is 2 in the detection medium.
This is the azimuth angle deviation of the magnetic tape with respect to the recording position of one detection signal, and if the distance between the track recording the detection signal and the track recording the reference signal on the detection medium and the frequency of the reference signal are constant, the azimuth of the magnetic head It is uniquely determined for the angular deviation. Therefore, the azimuth angle of the magnetic head can be detected from the number of read reference signals.

In a second aspect of the present invention, a plurality of detection signal tracks each having a plurality of magnetic transition points at equal intervals in the traveling direction at a plurality of positions on the azimuth angle in the recording pattern of the magnetic recording medium, A reference signal track having a magnetization transition point formed at an interval smaller than the interval of the magnetization transition point of the detection signal track is formed on the azimuth angle detection medium. Therefore, the positions of the magnetization transition points in the plurality of detection signal tracks in the azimuth angle detection medium coincide with the azimuth angle in the recording pattern of the magnetic recording medium, and the deviation of the azimuth angle of the magnetic head is in the plurality of detection signal tracks. Appears as a difference in the passage timing of the magnetization transition points in, and this difference is proportional to the number of magnetization transition points in the reference signal track. From this,
The azimuth angle deviation of the magnetic head can be obtained by counting the number of reference signals between the time when the magnetic head reads the detection signal from the azimuth angle detection medium and the time when the next detection signal is read.

According to the third aspect of the present invention, the number of read reference signals between the time when the magnetic head reads the detection signal and the time when the magnetic head reads the next detection signal is counted. The azimuth angle deviation of the magnetic head is obtained. Therefore, the azimuth angle of the magnetic head can be accurately detected from the number of read reference signals.

According to the fourth aspect of the invention, the mounting angle of the magnetic head is adjusted by using the calculation result of the azimuth angle calculating means of the azimuth angle detecting device as an input. Therefore, the magnetic head is mounted at an accurate mounting angle based on the accurate detection result of the azimuth angle deviation based on the counting result of the reference signal.

[0014]

1 is a diagram showing a running state of a magnetic tape in a magnetic head to which the azimuth angle detecting method for a magnetic head according to the present invention is applied. In the head unit 1 of the thin film magnetic head, the tape guides 3 are arranged on both sides of the head chip 2. The tape guide 3 contacts the tape running reference surface 5a at the upper or lower end of the magnetic tape 5 to define the running position of the magnetic tape 5. Head chip 2
A head gap 6 for reproducing the signal recorded on the tape is provided at the center of the. In such a structure, the azimuth angle θ of the head chip 2 means the angle formed by the head gap 6 and the tape running reference surface 5a.

FIG. 2 is a diagram showing a signal recording state in the azimuth angle detecting medium according to the embodiment of the present invention.
The test tape 5, which is an azimuth angle detection medium, is provided with two azimuth angle detection signal tracks 15 and 16 parallel to the tape reference plane 5a which coincides with the running direction of the test tape 5 shown by an arrow A in the figure. The reference clock recording track 17 is formed in the middle of these.
The magnetization transition points 21 and 31 in the upper and lower azimuth angle detection signal tracks 15 and 16 are formed on the vertical line of the tape running reference surface 5a. Furthermore, the reference clock recording track 17 includes tracks 15 for azimuth angle detection signals,
The magnetization transition points 41 to 44 and 41 'to 44' are formed at a pitch sufficiently smaller than the formation pitch of the 16 magnetization transition points. These azimuth angle detection signal tracks 15, 1
The magnetization transition point in 6 and the reference clock recording track 17 is a point where the magnetization polarity changes from N pole to S pole or from S pole to N pole.

In this embodiment, since the azimuth angle in the recording pattern of the ordinary magnetic recording medium is perpendicular to the tape running reference surface 5a in DCC, the azimuth angle detecting recording tracks 15 and 16 are also adjusted accordingly. Although the magnetization transition point at is formed on the vertical line of the tape running reference plane 5a, if the azimuth angle in the recording pattern does not match the vertical line of the tape running reference plane 5a as in a video tape used in a VTR, this recording is performed. Magnetization transition points of the azimuth angle detection signal tracks 15 and 16 are formed on the azimuth angle of the pattern.

As shown in FIG. 2, azimuth angle detection signal tracks 15 and 16 and reference clock recording track 17 are shown.
The test tape 5 on which the head is formed is shown in FIG.
When the head chip 2 is run against the
, The timing at which the magnetization transition point of the upper azimuth angle detection recording track 15 passes through the head chip 2 and the magnetization transition point 31 of the azimuth angle detection signal track 16 depend on the magnitude of the azimuth angle θ. There is a time lag with respect to the timing of passing through the head chip 2.
This time lag is caused when the magnetization transition points 41 to 44, 41 'to 44' of the reference clock recording track 17 are located in the head chip 2.
Appears as a change in the number passing through. Therefore, the azimuth angle θ of the head chip 2 can be known by counting the number of readings of the magnetization transition points of the reference clock recording track 17.

That is, in the test tape 5 formed in the state shown in FIG. 2, the distance between the azimuth angle detection signal track 15 and the reference clock recording track 17 on the vertical line of the tape running reference surface 5a is L, Assuming that the formation pitch of the magnetization transition points on the reference clock recording track 17 is p, the relationship of tan θ = 6P / 2L is established, and the azimuth angle deviation θ of the head chip 2 can be obtained.

FIG. 3 is a block diagram showing the configuration of an azimuth angle detecting device for a magnetic head according to the third aspect of the present invention. The azimuth angle detection device 20 includes a head drive circuit 9 that drives the head chip 2, a clock extraction circuit 10, a waveform shaping circuit 11, an azimuth determination circuit 12, and an azimuth display circuit 14. The head drive circuit 9 drives the head chip 2. The detection signal of the head chip 2 is amplified by the preamplifier included in the head drive circuit 9, and the reference clock recording track 1 of the test tape 5 is recorded.
The reference clock signal read from 7 is read by the clock extraction circuit 10.

On the other hand, the azimuth detection signal is supplied to the waveform shaping circuit 11 and undergoes signal waveform shaping. The rectangular wave output from the waveform shaping circuit 11 is the azimuth determination circuit 1.
2 is supplied. The azimuth determination circuit 12 determines the azimuth angle of the head based on the signals input from the clock extraction circuit 10 and the waveform shaping circuit 11. Specifically, the azimuth determination circuit 12 counts the reference clock signal output from the clock extraction circuit 10 while the next rectangular wave is input after being input from the waveform shaping circuit 11, and from this count value. Calculate the azimuth angle deviation θ. The determination result of the azimuth determination circuit 12 is supplied to the azimuth display circuit 14 and displayed outside on a display (not shown).

FIG. 4 is a block diagram showing the configuration of an azimuth angle adjusting device for a magnetic head according to the invention described in claim 4. In FIG. The azimuth angle adjusting device 30 includes an azimuth adjusting mechanism 13 in addition to the azimuth angle detecting device 20. This azimuth adjusting mechanism 13 has an azimuth judging circuit 1
The judgment result of 2 is supplied. The azimuth adjustment mechanism 13 adjusts the mounting angle of the head chip 2 in the head unit 1 according to the value of the azimuth angle deviation θ supplied from the azimuth determination circuit 12. That is, the azimuth adjusting mechanism 13 adjusts the mounting angle of the head gap 2 so that the value of the azimuth angle deviation θ supplied from the azimuth determination circuit 12 becomes zero.

FIG. 4 is a diagram showing a signal waveform of each part in the azimuth angle detecting device or the azimuth angle adjusting device of the magnetic head. The head chip 2 reads the azimuth angle detection signal and the reference clock signal from the test tape 5, and reads the read signals 15a and 16a and the reference clock signal 1.
7a is output. Read signal 15 of azimuth angle detection signal
a and 16a are amplified by the preamplifier and supplied to the waveform shaping circuit 11, and the rectangular wave signal 15 is supplied from the waveform shaping circuit 11.
b and 16b are output. On the other hand, the read signal of the reference clock signal is amplified in the preamplifier and then supplied to the clock extraction circuit 10, and the clock extraction circuit 10 outputs the rectangular-wave reference clock signal 17b. The azimuth determination circuit 12 receives the digital signal 15 based on the rectangular wave signals 15b and 16b of the azimuth angle detection signals 15 and 16, respectively.
Create c and 16c. Furthermore, this digital signal 15
The count signal 18 of the reference clock is created by taking the exclusive OR of c and 16c. This count signal 18 is "H
During i ", the number of inputs of the reference clock signal 17b supplied from the clock extraction circuit 10 is counted. With this, the azimuth determination circuit 12 obtains the azimuth angle deviation θ of the head chip 2 from the count value of the reference clock signal. You can

For example, when the head chip 2 has the azimuth angle deviation θ shown in FIG. 2, at the time t0 shown in FIGS. 2 and 5, the magnetization transition point 21 of the upper azimuth angle detection signal track 15 of the test tape 2 is changed. Head chip 2
Of the reference clock signal during the time t0 to the time t1 until the magnetization transition point 31 formed in the lower azimuth angle detection signal track 16 passes the head chip 2 at time t1. Are counted.

As described above, according to the embodiment of the present invention, the detection signal and the reference signal are recorded on the same test tape 5, and the azimuth of the head chip 2 is determined based on the number of reference signals read between the detection signals. Since the angular deviation can be detected, the number of reference signals read according to the azimuth angle of the head is constant regardless of the tape running speed, and an error occurred in the tape running speed during the adjustment work of the azimuth angle. Even in this case, the azimuth of the head can be accurately detected based on the number of read reference signals.

In the present embodiment, two tracks are formed on the test tape 5 as each detection signal track and one track is formed as a track for recording the reference clock, but this is the minimum required number of tracks. For example, by providing two recording tracks of the reference clock and inverting the respective magnetization polarities to form the magnetization transition points, it is possible to increase the resolution by halving the clock cycle.

[0026]

According to the present invention, a plurality of detection signals and reference signals recorded on the detection medium are read by the magnetic head, and the azimuth angle deviation of the magnetic head is calculated from the number of reference signals read between the two detection signals. Can ask,
The azimuth angle can be accurately measured with an inexpensive running mechanism without being affected by wow and flutter of the tape running system and tape speed. Further, since the judgment circuit counts the azimuth data on the basis of the reference signal from the detection medium, it can be constructed by a combination of simple logic circuits, and there is an advantage that the circuit can be simply and inexpensively produced.
In addition, since the azimuth angle is measured while the detection medium is running, the azimuth angle adjustment mechanism can be digitally controlled in real time based on the measurement result, and the mounting position of the magnetic head can be adjusted quickly and accurately. There are advantages.

[Brief description of drawings]

FIG. 1 is a diagram showing a running state of a magnetic head and a test tape using an azimuth angle detection method according to an embodiment of the present invention.

FIG. 2 is a diagram showing a recording state of a test tape which is the same azimuth angle detection medium.

FIG. 3 is a block diagram of an azimuth angle detecting device according to a third aspect of the invention.

FIG. 4 is a block diagram of an azimuth angle adjusting device according to a fourth aspect of the invention.

FIG. 5 is a diagram showing a signal state of each part in the azimuth angle detection device or the azimuth angle adjustment device.

[Explanation of symbols]

 1-head unit 2-head chip 5-test tape 6-head gap 12-azimuth judgment circuit 13-azimuth adjusting mechanism 15,16-track for azimuth angle detection signal 17-reference clock recording track

Claims (4)

[Claims] 1. A plurality of detection signals having a predetermined frequency and a reference signal having a frequency higher than the predetermined frequency of the detection signals are recorded on a detection medium, the signals are read from the detection medium through a magnetic head, and the detection signals are detected. Count the number of readings of the reference signal between reading and the next detection signal,
A method for detecting an azimuth angle of a magnetic head, characterized in that the azimuth angle of the magnetic head is obtained from this count value. 2. A plurality of detection signal tracks which are formed at a plurality of positions on the azimuth angle of a recording pattern on a magnetic recording medium and each have magnetization transition points at equal intervals in the traveling direction, and the detection signal tracks. A medium for detecting an azimuth angle of a magnetic head, comprising: a reference signal track having a magnetization transition point formed at an interval smaller than an interval of the magnetization transition point. 3. A reference signal counting means for counting a reference signal read from a detection medium by a magnetic head, and a reference signal counting means for counting the detection signal after the magnetic head reads the detection signal. An azimuth angle detecting device for a magnetic head, comprising: an azimuth angle calculating means for obtaining an azimuth angle of the magnetic head from the result. 4. An azimuth angle detecting device for a magnetic head according to claim 3, further comprising an azimuth angle adjusting mechanism for adjusting a mounting angle of the magnetic head by using a calculation result of the azimuth angle calculating means as an input. Azimuth angle adjusting device for magnetic head.