JPH0944829A - Tracking control device for magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a tracking control enabling a reproducing magnetic head to stably scan on-track position over whole range of the recording track by correcting track-curve data of the start point of the magnetic head scanning based on the track-curve data held in advance. SOLUTION: Curve pattern of a recording track is detected from a curve data holding circuit 111 which holds a curve data which showing multiple track curve patterns, and a comparison between a track curve data obtaining from magnetic heads 101, 102 and a track-curve data of the curve data holding circuit 111. And, a curve data detection circuit 110 correcting the track-curve data and electro-mechanical conversion elements (Piezo-electric effect elements) 103 is controlled based on the corrected curve-data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking control device for a magnetic recording / reproducing device.

[0002]

2. Description of the Related Art In a magnetic recording / reproducing apparatus such as a video tape recorder, when reproducing an information signal recorded on a recording track, a tracking control is carried out for the reproducing head to perform on-track reproduction scanning on the recording track. is necessary.

One that has been put into practical use as a tracking control method for video tape recorders is a magnetic head having different azimuth angles, and at least two parallel recording tracks simultaneously recorded on a magnetic recording medium are simultaneously reproduced and scanned. At least two reproducing magnetic heads having different azimuth angles (hereinafter referred to as reproducing pair heads) are used. Then, there is a method of detecting the track deviation of the reproducing pair head based on the time difference of the horizontal synchronizing signal reproduced from each magnetic head of the reproducing pair head. (For example, Japanese Patent Laid-Open No. 01-
In this method, it is not necessary to superimpose a tracking control signal (pilot signal) on the video signal, and time difference data indicating the track deviation of the reproducing pair head can be obtained from the time difference between the reproduced horizontal synchronizing signals. , A reproducing pair head is mounted on an electro-mechanical conversion element composed of a piezo piezoelectric element, etc., and a mechanical system of the magnetic head is changed using the time difference data to form a control system capable of following a track bend. You can

A tracking controller using the azimuth time difference detection method will be described below.

FIG. 9 is an explanatory diagram showing the relationship between the recording track recorded on the magnetic tape and the reproduction scanning position of the reproduction pair head.

FIG. 10 is an explanatory diagram showing changes in the reproduction time difference of the horizontal synchronizing signal when the scanning position of the reproduction pair head shown in FIG. 9 changes.

10A, the reproducing pair head 902 shown in FIG. 9 is at the on-track position (FIG. 9A).
At the position (a), the magnetic head 902A causes the recording track 90 to move.
The magnetic head 902B moves over the recording track 901B above 1A.
When you scan the above (the position to scan each correctly),
The horizontal synchronizing signal reproduced from each magnetic head of the reproducing pair head 902 is shown. FIG. 10B shows a horizontal synchronizing signal reproduced when the scanning position of the reproducing pair head 902 shown in FIG. 9 is shifted to the left on the paper surface from the on-track position (the position shown in FIG. 9B). FIG. 10C shows a horizontal synchronizing signal reproduced in a state where the scanning position of the reproducing pair head 902 shown in FIG. 7 is shifted to the right from the on-track position (the position of FIG. 9C). In FIGS. 10A, 10B, and 10C, H-SYNC (A) is a horizontal synchronization signal reproduced by the magnetic head 902A of the reproducing pair head 902, H-S.
YNC (B) indicates a horizontal synchronizing signal reproduced by the magnetic head 902B of the reproducing pair head 902.

In FIG. 9, reference numeral 903 denotes a recording track 90.
The horizontal sync signal is recorded in No. 1 and the arrow 904 indicates the direction in which the read pair head 902 scans the recording track 901. The horizontal synchronizing signal reproduced when the reproducing pair head 902 shown in FIG. 9 scans the on-track position (position of FIG. 9A) is as shown in FIG.
Data is reproduced from each magnetic head with a time difference T (= 0). The scanning position of the reproducing pair head 902 shown in FIG. 9 is shifted to the left on the paper from the on-track position.
When scanning the position of, the reproduction timing of the horizontal synchronizing signal reproduced by the magnetic head 902A is
The reproduction timing is earlier than the reproduction timing of the horizontal synchronization signal reproduced in 2B, and the reproduced horizontal synchronization signal is reproduced with a time difference T1 as shown in (b) of FIG. When the scanning position of the reproducing pair head 902 shown in FIG. 9 is shifted to the right on the paper surface from the on-track position, the position shown in FIG. 9C is scanned,
The reproduction timing of the horizontal synchronization signal reproduced by the magnetic head 902B is earlier than the reproduction timing of the horizontal synchronization signal reproduced by the magnetic head 902A, and the horizontal synchronization signal is reproduced with a time difference T2 as shown in (c) of FIG. To be done. By obtaining the time difference between the reproduced horizontal synchronizing signals, the track deviation direction and the deviation amount of the reproducing pair head 902 can be detected.

The reproducing pair head is mounted on an electro-mechanical conversion element, and the reproducing time difference of the horizontal synchronizing signal output from the reproducing pair head is reproduced by the reproducing pair head to scan the on-track position. N points per scan (N = 0) so as to approach T = 0)
By creating drive data that changes the electro-mechanical conversion element at sample points of () is an integer), the reproducing head can scan the on-track position even if there is a track bend.

Generally, the reproduction time difference data T obtained when the reproduction pair head reproduces and scans the on-track position is not always 0. The reason will be described. For example, when there is a difference in the mounting height of each magnetic head of the reproducing pair head, there is a time difference in each horizontal synchronizing signal obtained when the reproducing scanning is performed on the on-track position. In such a case, this time difference becomes T.

FIG. 8 is a block diagram showing the outline of a conventional tracking control device using the azimuth time difference detection method.

In FIG. 8, reference numerals 801 and 802 denote magnetic heads constituting a reproducing pair head having different azimuth angles and correspond to the magnetic heads 902A and 902B of FIG. 9, respectively. Reference numeral 803 is an electro-mechanical conversion element having the magnetic heads 801 and 802 mounted thereon, and 804 and 805 are magnetic heads 801 and 801.
An amplifier circuit for amplifying the reproduction signal reproduced from 802, and 806 and 807 are magnetic heads 8 of the reproduction pair head.
The horizontal synchronizing signal H-SYNC reproduced from 01, 802
(A), a signal processing circuit that outputs H-SYNC (B),
808 is the output H-SYNC (A), H-SYNC
(B) Time difference detection circuit for detecting reproduction time difference, 809
Is a drive data arithmetic circuit for arithmetically creating drive data for controlling the electromechanical conversion element 803 based on the reproduction time difference data output from the time difference detection circuit 808 and the reproduction output signal of the amplifier circuit 804, and 810 is drive data. The voltage corresponding to the output of the arithmetic circuit 809 is converted into the electro-mechanical conversion element 80.
3 is an electro-mechanical conversion element drive circuit to be applied to 3.

Regarding the tracking control device using the conventional azimuth time difference detection system configured as described above,
The operation will be described below.

The reproduced signals reproduced by the magnetic heads 801 and 802 are input to amplifier circuits 804 and 805, amplified and input to signal processing circuits 806 and 807. In the signal processing circuits 806 and 807, the horizontal synchronizing signals H-SYNC (A) and H-SYNC included in the respective reproduced signals inputted respectively.
(B) is output. Output horizontal sync signal H-SYN
C (A) and H-SYNC (B) are time difference detection circuits 808.
To the horizontal synchronization signal H-
A reproduction time difference between SYNC (A) and H-SYNC (B) is detected and reproduction time difference data is output. The output reproduction time difference data is input to the drive data operation circuit 809. The drive data operation circuit 809 samples a plurality of horizontal sync signals for one track, and the reproduction time difference data input to each sample point. When the reproducing head scans the on-track position, that is, when the reproducing output signal of the amplifier circuit 804 is maximized, the driving data of each sample point is calculated and output so as to match the reproducing time difference data T. The drive data output of each sample point output from the drive data operation circuit 809 is converted into a voltage by the electromechanical conversion element drive circuit 810 and applied to the electromechanical conversion element 803 to drive it.

FIG. 11 shows a conventional drive data operation circuit 809.
It is a block diagram of. 11, a terminal 1101 is a terminal to which reproduction time difference data is input, a terminal 1102 is a terminal to which a reproduction output signal of the amplifier circuit 804 is input, and 110
3, 1104 is a D / A circuit, and 1105 is a terminal 11 when the reproduction output signal input from the terminal 1102 becomes maximum.
A reference data setting circuit 1106 for detecting reproduction time difference data input from 01 and outputting it as reference data is D / A for each of the reproduction time difference data input from the terminal 1101 and the reference data output from the reference data setting circuit 1105. A comparison circuit 1107 for comparing the magnitudes of the results D / A converted by the circuits 1103 and 1104 is a comparison circuit 11
Depending on the result of 06, predetermined data (+ α, 0, −α: α
A data generation circuit for generating and outputting
Reference numeral 8 denotes an adder circuit, and 1109 denotes a delay circuit for delaying the data by a time t1 (a time corresponding to one rotation of the rotary drum) required to perform the next scan of the same reproducing head.

The operation of the drive data operation circuit 809 will be described below. In FIG. 11, first, in the first scanning of the reproducing head, the reference data setting circuit 1105 detects the reproducing time difference data when the reproducing output signal of the reproducing head becomes the maximum, and the detected reproducing time difference data is used for follow-up control. Set as standard data and output. In the second and subsequent scans, the comparison circuit 1106 compares the current reproduction time difference data input from the terminal 1101 with the reference reproduction time difference data set by the reference data setting circuit 1105. The data generation circuit 1107 according to the comparison result.
Then, the data of + α, 0, and −α are generated. That is, the reproduction time difference data (shown by Ts) input from the terminal 1101 and the reference reproduction time difference data (shown by Tr) are Ts>
Data of + α is generated when Tr, 0 is generated when Ts = Tr, and −α is generated when Ts <Tr is generated and output. Data generation circuit 11
The data output from 07 is added by the adder circuit 1108 to the data one scan before which is delayed by the delay circuit 1109 by t1, and the output data of the delay circuit 1109 is used as drive data for controlling the electro-mechanical conversion element 803. Is output.

FIG. 12 is an operation waveform diagram for explaining the operation of the drive data operation circuit 809.

In FIG. 12, (a) is a head switching signal (hereinafter referred to as an HSW signal), which is a signal for switching the reproducing pair heads of CH0 and CH1 mounted on the rotating drum so as to face each other at a position of 180 °. .
(B) is the reproduction detection output obtained by detecting the reproduction output signal, (c) is the time difference data (after D / A conversion) output from the reproduction pair head of CH0, and (d) is the output of the data generation circuit 1107. , (E) show the output of the delay circuit 1109. FIG. 12 shows the operation when the number of sampling points per scan is 7 (however, FIG. 12 shows the operation only for CH0).

First, in section 1 of FIG. 12, FIG.
When the reproduction detection output of is maximum, that is, in the same figure (c)
The time difference data at point C is set as a reference value. Next, the time difference data at each sample point in the same section is compared with the reference value set in the section 1 in FIG. Result of comparison Section 2 in the figure
(D) is generated from the data generation circuit 1107, and is added by the addition circuit 1108 in section 2 (e) of FIG.
As shown in, the data is output with a delay of the time t1 required for one scan of the same reproducing pair head. As a result of displacing the electromechanical conversion element 803 based on the output result of FIG. 6E, the reconstructed detection output of section 2 of FIG. 2B and the time difference data of section 2C of FIG. Is output. Section 2 in the figure
From the time difference data (c) and the reference value, the data shown in (e) of the section 3 in the figure is output from the data generation circuit 1107. Based on the data output from the data generation circuit 1107, the output of the addition circuit 1108 shown in (e) of section 3 in the figure is calculated to drive the electro-mechanical conversion element 803.
By repeating the above operation, the reproducing head can be controlled so that the reproducing output is always maximized, that is, the on-track position is always scanned.

[0020]

However, in the tracking control device of the above-mentioned conventional magnetic recording / reproducing apparatus,
Since the bending component of the recording track is detected only by the reproduction time difference of the horizontal synchronizing signal, the continuity of the horizontal synchronizing signal is lost near the switching of the reproducing heads facing each other at a position of 180 ° on the rotary cylinder. However, there is a problem that the track following control operation becomes unstable because the obtained reproduction time difference data is not reliable.

The present invention solves the above problems,
A plurality of pieces of reproduction time difference data indicating the bending patterns of the recording tracks are held as reproduction time difference data of different bending patterns, and the held reproduction time difference data is compared with the reproduction time difference data reproduced from the reproducing head. It is an object of the present invention to provide a tracking control device for a magnetic recording / reproducing device, which can perform a follow-up operation stably even near the switching of the reproducing head by correcting the reproduction time difference data based on the above.

[0022]

In order to achieve the above object, a tracking controller for a magnetic recording / reproducing apparatus of the present invention has at least two magnetic heads each having an azimuth angle different from each other, and a magnetic recording medium. At least two signals on which a plurality of synchronization signals are simultaneously recorded
In an apparatus for simultaneously reproducing two parallel recording tracks with a magnetic head, an electro-mechanical conversion element equipped with a magnetic head and a reproduction time difference between sync signals included in respective reproduction signals reproduced by two magnetic heads are detected. Difference detection means for outputting reproduction time difference information, bend data holding means for holding a plurality of track bend data, and comparison between the output of the time difference detection means and the bend data holding means for detection and correction of track bend data Based on the output of the drive data calculating means, and the drive data calculating means for calculating drive data for driving the electro-mechanical conversion element so that the reproduction output of the magnetic head is maximized. It is provided with an electro-mechanical conversion element driving means for driving the electro-mechanical conversion element.

[0023]

The tracking control device of the magnetic recording / reproducing apparatus having the above structure corrects the bending pattern at the reproduction scanning start point of the recording track on the basis of the preset bending pattern of the recording track, and drives the electro-mechanical conversion element. Since the drive data to be controlled is created by calculation, the follow-up control in the vicinity of the scanning start point of the reproducing head can be stabilized, a good reproduction output can be obtained over the entire recording track, and quick tracking control can be performed.

[0024]

1 is a block diagram of a tracking controller for a magnetic recording / reproducing apparatus according to a first embodiment of the present invention.

In FIG. 1, magnetic heads 101 and 102 are shown.
Constitute a pair head having different azimuth angles and are mounted on the piezoelectric element 103 as an electromechanical conversion element. The magnetic heads 101 and 102 are mounted on a rotating drum, respectively, facing each other at a position of 180 °.
It consists of 0 and CH1 heads. 104, 105
Is an amplifier circuit for amplifying the reproduction signal output from the magnetic heads 101 and 102, and 106 and 107 are signal processing circuits for processing the reproduction signal. The horizontal synchronizing signal H-SYNC reproduced by each head of the magnetic heads 101 and 102. (A), H
-Output SYNC (B). The output horizontal synchronizing signals H-SYNC (A) and H-SYNC (B) are input to the time difference detection circuit 108. The time difference detection circuit 108 detects a reproduction time difference between the horizontal synchronizing signals H-SYNC (A) and H-SYNC (B) and outputs time difference data. The time difference data output from the time difference detection circuit 108 is input to the bend data detection circuit 110. The bend data detection circuit 110 compares the input time difference data with the bend pattern of the bend data holding circuit 111 that holds a plurality of track bend patterns, and determines the bend pattern with the smallest absolute value error from the actual bend pattern time difference data. From the detected bending pattern, the time difference data in the vicinity of the scanning start point of the input time difference data is corrected by the method described below and output. The output corrected time difference data is input to the drive data calculation circuit 109. The drive data calculation circuit 109 sets the reproduction time difference data when the reproduction output of the amplifier circuit 104 is the maximum, and calculates the drive data so that the time difference data at each sample point on the recording track matches the reference value. Create and output. The drive data output from the drive data arithmetic circuit 109 is input to the electro-mechanical conversion element drive circuit 112. The electromechanical conversion element drive circuit 112 generates a voltage corresponding to the output of the drive data arithmetic circuit 109 and applies it to the piezoelectric element 103.

FIG. 2 is a block diagram of the bend data detection circuit 110 according to the first embodiment of the present invention.

In FIG. 2, a terminal 201 is a terminal to which time difference data is input, a terminal 202 is a terminal to which a plurality of preset bending data is input, and 203, 204 and 205 are N terminals input from the terminal 202 ( (N is a natural number)
Data selection 1 circuit for selecting the bending data for each bending data address and outputting the individual bending data,
Data selection 2 circuit and data selection N circuit, 206, 2
Reference numerals 07 and 208 denote time difference data input from the terminal 201 and data selection 1, 2, N circuits 203, 204, 20.
5, a comparison 1 circuit, a comparison 2 circuit, and a comparison N circuit, which perform comparison with individual bending data output from
0 and 211 are comparisons 1, 2, N circuits 206, 207,
The error detection 1 circuit, the error detection 2 circuit and the error detection N circuit which integrate the output results of 208 respectively, and the bend data correction circuit 212 are error detection 1, 2 and N circuits 20.
Bending data that minimizes the integration result of 9, 210, 211 is detected, and a data command signal 213 designating the address of the bending data that minimizes is output to the data selection A circuit 214. In the data selection A circuit 214, the bending data according to the data command signal 213 is converted into the bending data correction circuit 2
Output to 12. The bend data correction circuit 212 corrects the time difference data input from the terminal 201 according to the bend data input from the data selection A circuit 214, and outputs it to the terminal 215 as bend correction data.

FIG. 3 is a block diagram of the bend data holding circuit 111 in the first embodiment of the present invention.

In FIG. 3, reference numeral 301 is an address designating circuit for designating each bending data, 302 is a bending data circuit for storing bending data corresponding to each address of the addressing circuit 301, and 303 is N.
This is a data storage circuit that stores individual bending data at each sample point, and outputs the data to the terminal 304.

FIG. 4 is an explanatory diagram for explaining detailed operations of the bend data detection circuit 110 and the bend data holding circuit 111.

In FIG. 4, 401 is a time difference detection circuit 1.
08 output time difference data (in the figure, as an example,
8 shows the case where the bending data at the scanning start point is unstable by sampling 8 times on the recording track), and 402 shows the corrected time difference data output from the bending data detection circuit 110. The bend data in the bend data holding circuit 111 is, for example, four bend data 404, 405 shown in FIG.
The case where 406 and 407 are held is shown.

In the figure, the bend data detection circuit 11
At 0, the input time difference data 401 and the time difference data 404, 4 stored in the bend data holding circuit 111 are stored.
05, 406 and 407 are compared with each other to obtain an absolute value error for each of the time difference data 404, 405, 406 and 407 and the time difference data which minimizes the integrated value of the absolute value error is detected. As a result of the detection, the time difference data 406 is detected, and the input time difference data 401 is corrected by correcting the time difference data at the scanning start point as shown in FIG.
Output as time difference data of 2.

FIG. 5 is an operation waveform diagram for explaining the operation of the tracking controller of the magnetic recording / reproducing apparatus of the first embodiment of the present invention.

In FIG. 5, (a) is a switching reference signal (HSW signal), (b) is a reproduction detection output obtained by detecting the reproduction output output from the amplifier circuit 104, and (c) is output from the time difference detection circuit 108. (D) shows the corrected time difference data output from the bend data detection circuit 110, and (e) shows the drive data output from the drive data calculation circuit 109 for driving the piezoelectric element 103. . CH0 and CH1 in FIG. 3A indicate pair heads mounted on the rotary drum so as to face each other at 180 °. Reference numeral f in the figure indicates time difference data obtained by reproducing the scanning start point, and reference numerals g1, g2, g in the figure
Reference numeral 3 shows data obtained by correcting the time difference data at the scanning start point, reference numeral α in the figure shows the amount of change in drive data for driving the piezoelectric element 103, and reference numeral i in the figure shows the maximum reproduction detection output. The time difference data when In the figure, section 1 shows a section in which the follow-up operation is not performed, section 2 shows a section in which the follow-up operation is started, section 3 shows a section in which the follow-up operation is in progress, and section 4 shows a section in which the follow-up operation is completed. Show. In addition, the figure is an explanatory diagram of the follow-up operation of only CH0 for the sake of simplicity.

First, in section 1 of FIG. 5, the reference symbol f of the time difference data in FIG.
As a result, the time difference data at the scanning start point is corrected as indicated by reference numeral g1 in FIG. In section 1 of the figure, the drive data calculation circuit 109 sets the time difference data when the reproduction detection output becomes the maximum as the reference value.
Based on the set reference value, the corrected time difference data in FIG. 7D is set so that the corrected time difference data matches the reference value.
The drive data shown in is displaced by α. As a result of the change in the piezoelectric element 103 due to the displacement of the drive data, the reproduction detection output changes so that the reproduction detection output approaches the maximum as shown in section (b) of section 2 in FIG. As a result, the figure (c)
In the bend data detection circuit 110, the time difference data at the scanning start point is corrected again as the time difference data indicated by reference numeral g2, and the time difference data shown in FIG. Similarly, in the section 3 of the figure, the drive data of the figure (e) is displaced by α so that the corrected time difference data of the figure (d) matches the reference value set by the symbol i in the figure. By repeating the above operation, the drive data of section (e) in the same figure can be created, and the reproduction detection output obtained at that time is over the entire recording track as shown in (b) in the figure. You can get the maximum output. That is, the magnetic heads 101 and 102 can scan the on-track position.

As described above, according to the present embodiment, the bending data holding circuit 111 for holding the time difference data indicating a plurality of track bending patterns, and the magnetic head 10.
Bending data detection circuit for comparing the time difference data obtained by reproducing the data 1, 102 with a plurality of bending data of the bending data holding circuit 111, detecting the bending pattern of the recording track, correcting it to a predetermined time difference data, and outputting it. 11
0 is provided, and based on the corrected time difference data output from the bend data detection circuit 110, the piezoelectric element 103
By creating drive data for controlling the above, even if there is an unstable portion of the time difference data, it is possible to perform tracking control in which the magnetic head stably scans the on-track position over the entire recording track.

FIG. 6 is a block diagram of a bend data detection circuit according to the second embodiment of the present invention.

In FIG. 6, the difference from the bending data detection circuit 110 of FIG. 2 is that a terminal 601 to which an HSW signal for switching the reproduction timing of the magnetic head is input.
Then, based on the HSW signal input from the terminal 601, a detection timing signal 603 delayed by an uncertain time of the time difference data input from the terminal 201 (one sample period from the switching timing of the HSW signal) is output. This is the point that the switching circuit 602 is provided, and the respective error detection circuits 209, 210, 211 perform the operation of calculating and outputting the integrated value of the error only when the detection timing signal 603 is at the HIGH level.

FIG. 7 is an operation waveform diagram for explaining the operation of the bending data detection circuit of this embodiment.

In FIG. 7, (a) is the HSW signal,
(B) is the time difference data input from the terminal 201,
(C) is the bend data output from the bend data holding circuit 111 (in the figure, it is shown as the bend data when the output of the error detection circuit is minimized for ease of explanation), and (d) is the switching circuit 602. (E) shows the output of the error detection circuit when the bend data of FIG. 6 (c) is input. Reference numeral f in the figure is a portion of uncertain data of the time difference data, reference numeral j
Is a delay time from the switching timing of the HSW signal, and symbols k1 and k2 are outputs of the error detection circuit. Section 1 in the figure shows the state before the start of the follow-up operation, and section 2 and section 3 show the operation after the start of the follow-up operation. For the sake of explanation, this figure shows only the operation of CH0.

First, in section 1 of FIG. 7, the detection timing signal 603 output from the switching circuit 602 is delayed by the time j from the switching timing of the HSW signal of FIG. 7A as shown in FIG. Output a signal.
Based on this detection timing signal 603, each error detection circuit 209, 210, 211 obtains the integrated value of the error only when the detection timing signal 603 is at the HIGH level. The time difference data of (b) in the same section is the terminal 201.
When input from, the output of the error detection circuit is the minimum value k
The bend data which becomes 1 (shown in (e) in the same section) is detected as the bend data shown in (c) in the same section. Based on the detected bending data, the bending data correction circuit 212 corrects the data indicated by symbol f in the drawing in section 2 of the drawing, and starts the tracking operation. As a result, the time difference data in FIG. 7B is input again from the terminal 201, and again in FIG.
The error detection circuits 209, 210 and 211 obtain the integrated value of the error based on the detection timing signal 603 of FIG. As a result of the calculation, the minimum value of the output of the error detection circuit (indicated by symbol k2 in the same section) is obtained as shown in FIG. It is detected that the bend data when the output result of the error detection circuit is the minimum is the bend data shown in (c) of the same section 2, and in the section 3 of the figure, the bend data of the code f of the time difference data is bent. The data is corrected by the data correction circuit 212, and the tracking operation is started again. By repeating the same operation, the magnetic head can perform tracking control so that the on-track position can always be reproduced over the entire recording track.

As described above, according to this embodiment, the switching circuit 60 is used when comparing the time difference data to be reproduced with the bending data of a plurality of track bending patterns.
By using the detection timing signal 603 output from No. 2, the track bend can be detected with high accuracy, and the indefinite time difference data portion is corrected based on the detected bend data, and the corrected bend data is obtained. By controlling the piezoelectric element 103 on the basis of the above, the magnetic head can more stably read and scan the on-track position over the entire recording track more stably.

In the above embodiments, the normal reproduction is explained, but in the magnetic recording / reproducing apparatus for performing special reproduction by using the piezo piezoelectric element, in order to correct the bending of the recording track learned during the normal reproduction during the special reproduction. By storing the follow-up control data created in 1 above, it can be used even during special reproduction.

[0044]

As described above, according to the present invention, the bending pattern of the recording track is detected from the bending data holding circuit for holding the bending data indicating a plurality of track bending patterns and the time difference data obtained from the magnetic head, and the predetermined bending pattern is detected. By providing a bend data detection circuit that corrects the time difference data, the magnetic head records stably over the entire recording track even if normal time difference data cannot be obtained near the scanning start point of the magnetic head or due to lack of reproduction output. Tracking follow-up control capable of reproducing and scanning the on-track position on the track can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of a tracking controller of a magnetic recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a bend data detection circuit of the same embodiment.

FIG. 3 is a block diagram of a bend data holding circuit according to the same embodiment.

FIG. 4 is an explanatory diagram for explaining operations of a bend data detection circuit and a bend data holding circuit of the same embodiment.

FIG. 5 is an operation waveform diagram for explaining an operation of tracking follow-up control of the same embodiment.

FIG. 6 is a block diagram of a bend data detection circuit according to a second embodiment of the present invention.

FIG. 7 is an operation waveform diagram for explaining the operation of the bending data detection circuit of the same embodiment.

FIG. 8 is a block diagram of a tracking control device using a conventional azimuth time difference detection method.

FIG. 9 is a schematic diagram for explaining a conventional azimuth time difference detection method.

FIG. 10 is a waveform diagram for explaining a conventional azimuth time difference detection method.

FIG. 11 is a block diagram of a conventional drive data operation circuit.

FIG. 12 is an operation waveform diagram for explaining the operation of a conventional drive data operation circuit.

[Explanation of symbols]

 101, 102 Magnetic head 103 Piezo-piezoelectric element 108 Time difference detection circuit 109 Drive data calculation circuit 110 Bending data detection circuit 111 Bending data holding circuit 112 Electro-mechanical conversion element drive circuit 203, 204, 205 Data selection circuit 206, 207, 208 Comparison Circuits 209, 210, 211 Error detection circuit 212 Curved data correction circuit 214 Data selection A circuit 301 Addressing circuit 302 Curved data circuit 303 Data storage circuit 602 Switching circuit

Claims (2)

[Claims] 1. A magnetic recording medium having at least two magnetic heads each having a different azimuth angle, and at least two parallel recording tracks on which signals including a plurality of synchronization signals are simultaneously recorded. In an apparatus for simultaneously reproducing with a head, an electro-mechanical conversion element equipped with the magnetic head and a reproduction time difference information of the synchronization signal included in each reproduction signal reproduced by the two magnetic heads are detected to reproduce reproduction time difference information. Is output, the bend data holding means for holding a plurality of track bend data, and the output of the time difference detecting means and the output of the bend data holding means are compared to detect and correct the track bend data. Bending data detecting means, and the bending data output from the bending data detecting means and the reproduction signal. Even without 1
Drive data calculation means for calculating and generating drive data for driving the electro-mechanical conversion element in the vertical direction with respect to the recording track by using one reproduction signal as input, and the electric data calculation means based on the output of the drive data calculation means. A tracking control device for a magnetic recording / reproducing apparatus, comprising: an electro-mechanical conversion element driving means for driving the mechanical conversion element. 2. The bending data detecting means has a switching means for changing the detection timing of the track bending data based on a reference signal for switching the reproduction timing of the magnetic head, and the track according to the output of the switching means. 2. The tracking control device for a magnetic recording / reproducing apparatus according to claim 1, wherein the timing at which the bending data and the reproduction time difference information are compared is changed.