JPS6252382B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording/reproducing device that records signals concentrically on a recording medium, and conventionally, an effective method for increasing the areal density of recorded signals on a recording medium is to shorten the recording track width. However, when recording and reproducing this signal, tracking becomes a difficult problem, whereas the present invention simplifies and easily realizes tracking when recording with a narrow track width.

As an example of a conventional disk-type magnetic recording/reproducing device, a device as shown in FIG. 1 will be described below. The magnetic sheet 1 is rotated in the vicinity of the stabilizing plate 3 by a motor 2. When the rotation of the magnetic sheet 1 becomes faster, the air around the magnetic sheet 1 flows along the sheet 1, forming a stable laminar flow with the stabilizing plate 3, and the magnetic sheet 1 obtains a stable rotating surface. A magnetic head 4 is brought into contact with this to perform recording and reproduction. The magnetic head 4 is mounted on a headblock 5, which can be moved in the radial direction of the magnetic sheet 1 by a step motor 6.

FIG. 2 is a detailed view of the magnetic head section, in which the video head 4 is connected to the head block 5 via the piezo element 7.
When a voltage is applied to the terminals 8 and 9, the piezo element 7 warps, allowing the video head 4 to move in the width direction of the track. FIG. 3 shows signal traces recorded on the magnetic sheet 1. The inner hole 10 is the attachment part of the magnetic sheet 1, and the motor 2
The seat holder 11 is fitted to the seat holder 11 provided on the rotating shaft.

Now, in the above-mentioned devices, as the recording density increases and the track width becomes narrower, the problem arises that, for example, due to eccentricity due to slight fitting in the magnetic sheet holding portion 11, the recorded signal trace cannot be traced during reproduction. occurs. For example, if the recording track 12 and the reproducing track 13 are moved by δ due to eccentricity as shown in FIG. 4a, the output voltage of the magnetic head 4 is approximately proportional to the effective track width.
It fluctuates as shown in Figure 4b. As a matter of course,
This type of mistracking that causes output fluctuations of the magnetic head 4 must be suppressed as much as possible.

The present invention is effective in solving this type of problem, and one embodiment thereof will be described below based on the drawings.

In FIG. 5, during reproduction, the reproduction voltage of the magnetic head 4 is amplified by the head amplifier 14 and transmitted via the terminal 15 to the original signal processing circuit (not shown). A part of the signal at the terminal 15 is envelope-detected by an envelope detector (abbreviated as ED) 16 of the reproduced signal, and the signal is transmitted to an AD converter (abbreviated as A/D) 17 and converted into a digital signal. Ru. A gear 18 coaxial with the magnetic sheet 1 driven by a motor 2 is paired with a detector 19 to form a frequency generator (FG).
A signal corresponding to the mechanical rotation angle of the magnetic sheet is applied to a pulse forming circuit (PA) 21 to perform pulse forming. A computer is connected to this system. The computer has a central processor unit (abbreviated as CPU) 22, subchannel adapters (abbreviated as SCA and SCA) 23, 24, random access memory (abbreviated as RAM) 25, read-only memory (abbreviated as ROM) 26, etc., connected to the bus. It has a configuration connected by .

Now, the signal of FG20 is pulse-shaped by PA21, and given to A/D17 as a conversion command via SCA24, CPU22, SCA23, etc., and the output of A/D17 is read into CPU22 via SCA23, and the corresponding one is stored in RAM25. It is placed at the address to be specified. A similar operation is performed with the next signal from PA 21, but all these instructions are stored in ROM 26. When the magnetic sheet 1 rotates once in this way, the number sequence corresponding to the mistracking obtained by envelope detection is transferred to the RAM 2.
5.

Now consider the case where a specific track is to be played. After one revolution of measurement, the magnetic head 4 is moved slightly in the track width direction and similar measurements are made, followed by arithmetic processing. By repeating this, it is possible to obtain a deviation of the recorded track from the reproduced track, that is, a tracking pattern.

FIG. 6 shows an example where the eccentricity δ in FIG. 4 exceeds the track width W. 6a to 6f illustrate the output voltage of the magnetic head when the track position during reproduction is slightly shifted. As is clear from FIG. 6, signals of the same track have the characteristic of being symmetrically out of phase, so it is possible to recognize this and obtain a tracking pattern through computational processing. RAM
When a signal has already been recorded on the track to be recorded, it is most preferable to detect the tracking pattern arranged on the track 25. However, if the area is unrecorded, a tracking pattern cannot be obtained. In this case, it is preferable to use adjacent recorded tracks.

A specific example of the track pattern detection method described above is shown below. For example, suppose that a video head having a piezo element 7 as shown in FIG. 2 is arranged as the video head 4 in FIG. Thus, when applying the DC voltage to the piezo element 7 through the terminals 8 and 9, the applied voltage is programmed to be a certain voltage _E1 . Next, suppose that the reproduction voltage of the magnetic head 4 at this time is as shown in FIG. 6a in terms of time. This reproduction voltage is counted as a digital quantity for each timing pulse generated by the FG 20, and programmed to be stored in the RAM 25. When this accumulation is completed after one more revolution, the DC voltage applied to piezo element 7 is slightly increased from E ₁ through terminals 8 and 9.
Set it in the program so that it becomes _E2 . Thereafter, the output of the magnetic head 4, for example, the voltage waveform shown in FIG. 6B, is counted and stored for each timing pulse generated by the FG 20 according to the program. If the same operation is repeated thereafter, the waveforms shown in FIGS. 6a to 6f, for example, will be stored in correspondence with the angles in the circumferential direction of the FG 20, that is, the magnetic sheet 1. When the magnetic head 4 just aligns with the recording track, the reproduction voltage is at its maximum, so by calculating the point at which this maximum voltage is generated, conversely, the voltage applied to the piezo element 7 at which the maximum voltage is generated can be calculated. Since the voltage is known, the tracking pattern of the recording track can be obtained from it. The measurement accuracy of the tracking pattern is mainly determined by the number of teeth of the FG 20 and the number of voltage fluctuations to the piezo element 7. The arithmetic processing may be performed for each accumulation, and in this case, the capacity of the RAM 25 can be reduced.

When recording using the tracking pattern obtained in this way, a magnetic head is placed on the track to be recorded, the tracking pattern is sequentially output from the SCA 24 according to the signal from the FG 20, and the tracking pattern is transferred to the DA converter. (abbreviated as D/A)2
8 converts it into an analog signal, amplifies it to an appropriate level by a driver amplifier (abbreviated as DA) 29, and applies it to the terminals 8 and 9 of the piezo element 7, so that the magnetic head 4 moves according to the tracking pattern. It can be displaced and recorded with a complete track. Needless to say, at this time, the magnetic head is connected to the recording amplifier (abbreviated as A) 30 side.

During reproduction, the magnetic head 4 remains connected to the HA 14, so that a closed loop can be formed. In this case, the program in the ROM 26 can determine whether it is a tracking pattern shift or a disturbance component such as a dropout. Of course, it is also possible to use it as an open loop, and this can be considered in the same way as when recording. Incidentally, the slight movement of the magnetic head in the track width direction can be easily realized by programmatically using a piezo element.

Furthermore, as described above, signals of the same track will be symmetrically shifted in phase if the reproduction head is shifted little by little. Therefore, this characteristic can be detected by computer processing, and instead of repeating the slight movement a predetermined number of times to obtain a tracking pattern, it is also possible to adjust the amount of eccentricity.

Although the present invention uses a magnetic recording medium as an example, other recording bodies may be used in the same way.

As described above, according to the present invention, a tracking pattern of a recorded track is measured and a new track to be recorded is formed using the tracking pattern, so that high-density recording on a magnetic sheet or the like becomes possible. In the case of tracking, the calculation process by the computer is performed in units of one rotation, so that the measurement time can be shortened and the measurement can be carried out efficiently. In addition, the distortion of the screen that occurs when the head is forcibly excited at a high frequency to find the peak of the envelope does not occur.

Since the track pattern is measured near the recording track, even if there is local deformation or uneven elongation of the recording medium, it can be corrected and absorbed. This is particularly advantageous when using an accessible recording medium such as a magnetic sheet.

Measurements are made by making slight movements each time the recorder goes around, so
It has high accuracy, and even if a dropout occurs temporarily, it can be estimated from before and after.

If this configuration is used in a closed loop during playback, ie, when the heads are moved sequentially, the accuracy of the track pattern can be greatly improved if this micro-movement detection is also used.

With such a simple configuration, recording media can be exchanged, stored, and interchanged between machines.

The computer can be an ultra-compact computer such as a microprocessor and has a simple circuit.
This method is particularly effective because recording materials such as magnetic sheets undergo irregular deformation due to temperature, humidity, and the like. Of course, it is most preferable for the tracking pattern to be measured near the recording track. When using a computer to determine conditions such as measurement, there is a degree of freedom in selecting a program according to its purpose, so it can be expanded to a certain degree of application.

[Brief explanation of the drawing]

1 to 3 are configuration diagrams showing an example of a disc-shaped magnetic recording/reproducing device, FIGS. 4a and 4b are explanatory diagrams showing an example of a tracking pattern, and FIG. 5 shows an embodiment of the present invention. The block diagram in FIG. 6 is a characteristic diagram showing changes in head output when the amount of eccentricity is large. 1... Magnetic sheet, 2... Motor, 4... Magnetic head, 7... Piezo element, 16... Envelope detector (ED), 20... Frequency generator (FG), 22... Central processor (CPU),
25...Random access memory (RAM), 26...
Read-only memory.

Claims (1)

[Claims] 1. In a recording and reproducing device that records signals concentrically on a recording medium, the reproduction signal of the recording and reproducing element is measured for a recorded track near the track position to be recorded during recording when the recording medium rotates once. repeating the measurement by slightly moving at least one of the recording/reproducing element or the recording medium stepwise in the track width direction, and calculating by a computer a change in the reproduction signal of the recording/reproducing element corresponding to the slight movement; A magnetic recording/reproducing apparatus configured to obtain a tracking pattern of the recorded track of the recording medium and to record using the tracking pattern.