JPH04181513A - Magnetic recording reproducing apparatus - Google Patents

Abstract

PURPOSE:To improve the image quality by operating the driving waveform of a head based on previous errors and obtaining the driving pattern of a not reproducing side by inverting the time axis of the previous pattern of a reproducing side. CONSTITUTION:An output signal of a magnetic head 5 is, through a head amplifier 14, input to an envelope detecting circuit 15, whereby an envelope is detected. The analog signal of the output signal is converted by an A/D converter 16 and sent to an error accumulating/storing device 18. The shifting amount of the scanning position of the magnetic head to a recording track for each trial is detected, accumulated and stored. The driving of the head suitable for speed search or the like generated by a waveform generating device 17 and the accumulated error in the device 18 are inputted to a waveform operating device 19, thereby operating the waveform of the head. The driving waveform of a head actuator 4b at the last time is inversely read and added through a converter 21 and a head driver 20 for every sampling time. The head 5 is driven by a current corresponding to the driving waveform, and the current is amplified by the amplifier 14. n this manner, an error is decreased for every trial, thereby ensuring the high image quality.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a helical scan type magnetic recording/reproducing device capable of displacing a magnetic head in a direction perpendicular to a scanning direction, and particularly relates to a head image forming method thereof. This relates to an improved version of .

[Conventional technology]

NE (Noise Erase) of magnetic recording and reproducing equipment
The head can be displaced in a direction perpendicular to the scanning direction, and during special playback such as speed search, by driving the head so as to trace only a single track, the head can be moved in a direction perpendicular to the scanning direction. When special playback is performed using the head, noise bars appearing on the screen can be prevented because the head crosses multiple tracks.

By the way, in reality, the track during normal playback is not perfectly straight, but has a slight curvature, so in order to accurately trace this and improve the image quality, the NE head is used even during normal playback. Consideration is being given to whether it can be used for regeneration.

FIG. 3 is a diagram showing a head control system of a conventional magnetic recording/reproducing apparatus of this type, as disclosed in, for example, Japanese Patent Application No. 1-256784. In the figure, 1 is a fixed drum, 2 is a rotating drum, and 3 is a tape, which are mounted so as to run obliquely over about 190 degrees along a tape guide groove provided on the fixed drum 1. 4a and 4b are magnetic heald actuators attached to the rotating drum 2 at an angle of 180°. Further, 14 is a head amplifier that amplifies the output signal of the magnetic head 5, 15 is an envelope detection circuit that detects the FM envelope signal and detects the envelope, and 16 is an A/D converter that converts the analog signal into a digital signal. It is.

Also, ]7 is the trajectory on the tape (
18 is an error accumulation storage device that detects and cumulatively stores the amount of relative positional deviation of the head at each sampling; 19 is the information 20 is a head driver for driving the Herad actuator; 21 is a D/A converter for converting digital signals into analog signals;
Reference numeral 22 denotes a non-reproduction side pattern correction device that corrects the head drive pattern on the non-reproduction side (back side of the drum) so that it is smoothly connected to the head drive pattern on the reproduction side at the initial point and end point.

FIG. 4 is a diagram showing a magnetic head actuator that moves the magnetic head along the drum axis.

In the figure, 5 is a magnetic head, 6 is a coil bobbin, and 6 is a magnetic head.
a is a cylindrical bobbin, and 6b is a fill.

7a is a first gimbal spring, 7b is a second gimbal spring, and 8a is a first attachment member, which firmly fixes one end of the coil bobbin 6 and the gimbal spring 7a. 8b is the second
The other end of the coil bobbin 6 and the gimbal spring 7b are firmly fixed with the mounting member. Reference numeral 9 denotes a cylindrical outer yoke, which has an inner diameter larger than the diameter of the coil bobbin 6 and is made of a material with high magnetic permeability. Reference numerals 10a and 10b are disk-shaped outer circumferential yaws made of a material with high magnetic permeability, and are fixed to both ends of the circular outer circumferential member 9. lla and llb are cylindrical permanent magnets. A center ball 12 is coaxially arranged within the cylindrical yoke 9 with permanent magnets 11a and Ilb arranged at both ends, and is fixed with adhesive to form a magnetic circuit. A coil bobbin 6 is inserted through the center ball 12, and is held movably in the axial direction by gimbal springs 7a and 7b. A leaf spring 13 is a head mounting member, one end of which is fixed to the coil bobbin 6, and the magnetic head 5 is fixed to its free end.

Next, the operation will be explained. ” The output signal of the magnetic head 5 is amplified by the head amplifier 14, and its envelope is detected by the envelope detection circuit 15.The analog signal is converted into a digital signal by the A/D converter 16 at every sampling time ΔT. The error is sent to the error accumulation storage device 18.The error accumulation storage device 18 detects the deviation between the envelope line and the specified value and calculates the amount of scanning position deviation e(k) of the magnetic head with respect to the recording track of each trial (one track of the tape). ΔT) (here, k indicates the number of sampling times) is detected and stored cumulatively for each trial as shown in equation (1).

ADERR,, (k-ΔT)=Σ-e+Oc-ΔT)
・(1) (j is the number of trials) The waveform calculation device 19 includes the head drive waveform X d (k・ΔT) generated by the waveform generator 17 and suitable for a running mode such as speed search, and the above-mentioned error accumulation. Storage device 1
The cumulative error ADERR+-+ (k・
ΔT) is input, and the next (jth) head drive waveform Xc+(k·ΔT) shown in equation (2) is calculated and sent to the D/A converter 21 via the non-reproduction side pattern correction device 22. .

Xc+(k・ΔT)=Xd(k−ΔT)+γ ADE
RR, , (k · ΔT) ... (2) Here, γ indicates the learning control gain.

The non-reproduction side pattern correction device 22 extracts the reproduction side pattern from among the head drive waveforms sent from the waveform calculation device 19, and calculates the positions of its initial point and end point.

Find velocity and acceleration using numerical differentiation, etc. Next, it takes 16, 7ms to satisfy the position, velocity, and acceleration of the initial point and end point.
That is, a waveform for a period corresponding to a half cycle of the synchronizing signal shown in FIG. 3 is obtained as an interpolated waveform, such as a six-dimensional equation regarding time.

Finally, the non-reproduction side pattern obtained in the above manner is connected to the reproduction side pattern and output to the D/A converter 21 at every sampling time ΔT.

The D/A converter 21 converts the digital signal from the non-reproducing side pattern correction device 22 into an analog signal and outputs it to the head driver 20. The head driver 20 drives the magnetic head 5 by applying a current to the coil of the magnetic head actuator 4 according to the head drive waveform. As the magnetic head moves, the jth trial of tracing is completed. The magnetic head output at this time is again amplified and extracted by the head amplifier I4. The above process is then repeated in sequence for each synchronization signal.

[Invention or problem to be solved]

Since the head control device of a conventional magnetic recording/reproducing device is configured as described above, in order to improve accuracy, a non-reproducing side pattern correction device is required to smoothly connect the initial point on the reproducing side and the ending point on the non-reproducing side. However, there were problems such as the time required to calculate the correction pattern and the high cost.

This invention was made to solve the above-mentioned problems, and achieves a highly accurate learning control method by aligning the initial point on the reproducing side and the ending point on the non-reproducing side without using a non-reproducing pattern correction device. The purpose is to obtain a magnetic recording/reproducing device that can perform the following steps.

[Means to solve the problem]

The magnetic recording/reproducing device according to the present invention includes an error accumulation storage device that cumulatively stores the amount of relative positional deviation for each sampling, and a waveform calculation device that determines the next head drive waveform based on the information. As the error is added to the current command value and the trial is repeated, the next head drive waveform is calculated so that the error becomes small.
It is configured to be read out with the time axis reversed.

[Effect]

In this invention, the head drive waveform is calculated based on the previous error, and the previous reproduction drive pattern is read out with the time axis reversed to obtain the non-reproduction drive pattern. A pattern correction device on the non-reproduction side is not required, and a learning control method that is inexpensive and reduces errors as trials are repeated can be realized, and high image quality can be obtained.

〔Example〕

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

FIG. 1 is a block diagram showing a head control device of a magnetic recording/reproducing device according to an embodiment of the present invention, and in the figure,
The same reference numerals as in FIG. 3 indicate the same or corresponding parts.

FIG. 2 is a diagram showing a head driving pattern according to an embodiment of the present invention.

Next, the operation will be explained.

As in the conventional example, the output signal of the magnetic head 5 is amplified by the head amplifier 14, and its envelope is detected by the envelope detection circuit 15. The analog signal is converted into a digital signal by the A/D converter 16 at every sampling time ΔT and sent to the error accumulation storage device 18. The error accumulation storage device 18 stores the amount of scanning position deviation e(k·
ΔT) (where k indicates the number of sampling times) is detected and stored cumulatively for each trial as shown in the fl1 formula.

ADHRR,, (k-ΔT)=Σe+(k・ΔT)・
(1) (j is the number of trials) The waveform calculation device 19 stores the head drive waveform X d (k·ΔT) suitable for a running mode such as speed search generated by the waveform generator 17 and the error accumulation storage device described above. 18
Cumulative error ADBRR stored in , (k・△T)
is input, and the next (jth) head drive waveform Xc+(k·ΔT) shown in equation (2) is calculated.

Xc+(k・ΔT)=Xd(k−ΔT)×γ ADER
R1−+(k·ΔT) (2) Here, γ indicates the learning control gain.

Now, if the j-th head drive waveform of the head actuator 4a on the playback side is Xc+a(k・ΔT), then the head drive waveform of the head drive actuator 4a on the playback side is Xc ra(k・ΔT)
is the D/A converter 21. at every sampling time ΔT. It is applied via the head driver 20. At this time, the drive waveform of the previous drive actuator 4b stored in the waveform calculation device 19 is read in reverse and stored in the drive waveform of the drive drive actuator 4b on the non-reproducing side Xc, -, b (16, 67 -
k ・6 guns) is still D/ for each sampling time ΔT.
A converter 21. It is applied via the head driver 20. FIG. 2 shows the driving pattern for the head actuator 4a at this time. As shown in FIG. 2, it can be seen that the reproducing side and the non-reproducing side are smoothly connected.

A current corresponding to these drive waveforms is passed through the coil of the Herad actuator 4 to drive the magnetic head 5. The magnetic head output at this time is again amplified and extracted by the head amplifier 14. The above process is then repeated for each synchronization signal.

In the first embodiment, the waveform generator 17.degree. error accumulation storage device 18. Although the waveform calculation device 19 is composed of separate elements, it goes without saying that one component such as a microcomputer, etc.
Of course, one element can be replaced with one that can perform the same processing.

Further, the present invention is not limited to the above-described embodiments, and can take various configurations without departing from the gist of the present invention.

〔Effect of the invention〕

As described above, the magnetic recording/reproducing apparatus according to the present invention includes an error accumulation storage device and a waveform calculation device that cumulatively store the relative positional deviation amount of the magnetic head for each sampling, and calculates the amount of relative positional deviation of the magnetic head based on the previous error. In addition to calculating the head drive waveform, the non-reproduction side drive pattern is determined by reading out the previous reproduction side drive pattern with the time axis reversed, so a non-reproduction side pattern correction device is not required. , a learning control method that reduces errors as trials are repeated can be realized at low cost, and has the effect of obtaining high image quality.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a head control device of a magnetic recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a diagram showing a head drive pattern according to an embodiment of the present invention, and FIG. FIG. 4 is a block diagram showing the head control device of the reproducing apparatus, and is a sectional view of the magnetic head actuator. In the figure, l is a fixed drum, 2 is a rotating drum, 3 is a tape, 4 is a magnetic head actuator, 14 is a head amplifier, 15 is an envelope detection circuit, 16 is an A/D converter, 17 is a waveform generator, 18 is the error accumulation storage, 1
9 is a waveform calculation device, 20 is a head driver, 21 is a D/
It is an A converter. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A magnetic head drive device that displaces a magnetic head mounted on a rotating drum and attached to a driven part in a direction perpendicular to its scanning direction; a relative positional deviation amount detection means for detecting the amount of scanning positional deviation; an error accumulation storage device that cumulatively stores the amount of relative positional deviation between the track and the head for each sampling; In a magnetic recording/reproduction device, the waveform calculation device is equipped with a waveform calculation device that calculates and determines the next head drive waveform, and a head driver that drives the reproduction side and non-reproduction side heads. What is claimed is: 1. A magnetic recording and reproducing apparatus, characterized in that the head drive waveform on the non-reproduction side is generated by reversing the time axis and reading out the previous head drive waveform on the reproduction side.