JP3225584B2 - Tracking control 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 tracking control device for a magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art In a magnetic recording / reproducing apparatus, when an information signal recorded on a recording track is reproduced, it is necessary to perform tracking control for a reproducing head to perform on-track reproducing scanning on the recording track.

In a tracking control method that has been put into practical use, a dedicated control track is provided in the longitudinal direction of the tape, and a control signal is recorded at a frame period or a period that is an integral multiple of the frame period. There is a method of performing tracking control by using such a method. However, this method has drawbacks such as the necessity of a dedicated control track and the inability to obtain a tracking error signal over the entire area of the recording track.

Another method that has been put into practical use is to simultaneously reproduce and scan at least two parallel recording tracks recorded on a magnetic recording medium with magnetic heads having different azimuth angles. There is a method of using a reproducing head (hereinafter referred to as a reproducing pair head) and detecting a track shift of the reproducing pair head based on a time difference between horizontal synchronization signals reproduced from the respective reproducing pair heads. In this method, it is not necessary to superimpose a tracking control signal (pilot signal) on the video signal, and it is possible to obtain time difference data indicating the track deviation of the reproduction pair head from the time difference of the reproduced horizontal synchronization signal. When mounted on an electro-mechanical conversion element constituted by a piezoelectric element or the like and the mechanical position of the head is changed using the time difference data, a control system capable of following the track bend can be constituted. Hereinafter, a tracking control device using the azimuth time difference detection method will be described. FIG. 6 shows a change in the reproduction time difference of the horizontal synchronization signal depending on the position of the recording track recorded on the magnetic tape and the position of the reproduction pair head. 6A is a plan view showing the positional relationship between the reproducing pair head 602 having different azimuth angles and the recording track 601. FIG. 6B is a drawing showing the reproducing pair head when the reproducing pair head 602 scans the on-track position. 602 shows a horizontal synchronization signal reproduced from each head. FIG. 9C shows a horizontal synchronizing signal reproduced when the scanning position of the reproducing pair head 602 is shifted to the left on the paper from the on-track position. FIG. 9D shows a horizontal synchronization signal reproduced when the scanning position of the reproducing pair head 602 is shifted to the right on the paper from the on-track position.
In FIGS. 6B, 6C and 6D, H-SYNC is used.
(A) shows a horizontal synchronization signal reproduced by the magnetic head A of the reproduction pair head 602; H-SYNC (B) shows a horizontal synchronization signal reproduced by the magnetic head B of the reproduction pair head 602.

In FIG. 1, reference numeral 603 denotes a horizontal synchronization signal recorded on a recording track, and arrow 604 indicates a direction in which the reproducing pair head 602 scans the recording track.
The horizontal synchronizing signal reproduced when the reproducing pair head 602 scans the on-track position is reproduced from each head with a time difference T (= 0) as shown in FIG. When the scanning position of the reproducing pair head 602 is shifted to the left on the paper from the on-track position, the reproduction timing of the horizontal synchronization signal reproduced by the magnetic head A is changed to the magnetic head B.
(C), the reproduced horizontal synchronizing signal is reproduced with a time difference T1 as shown in FIG. 3 (c), and the scanning position of the reproducing pair head 602 is on the paper from the on-track position. When it is shifted to the right, the reproduction timing of the horizontal synchronizing signal reproduced by the magnetic head B is earlier than the reproduction timing of the horizontal synchronizing signal reproduced by the magnetic head A, and as shown in FIG. The horizontal synchronization signal is reproduced. By calculating the time difference between the reproduced horizontal synchronizing signals, it is possible to detect the direction and the amount of track shift of the read pair head 602.

A reproduction pair head is mounted on an electro-mechanical conversion element, and a reproduction time difference of a horizontal synchronizing signal output from the reproduction pair head is made closer to time difference data T obtained when the reproduction pair head performs reproduction scanning of an on-track position. By generating drive data for changing the electro-mechanical transducer at N sample points (N is an integer) per scan, the reproducing head can scan the on-track position even if the track is curved.

[0007]

However, when the tape speed changes, the electro-mechanical conversion element is displaced in response to the change in the tape speed, and special reproduction is possible in which the reproducing head can follow the recording track. In a magnetic recording / reproducing device,
There was a problem that a good reproduction output could not be obtained only by following the recording track by a drive pattern waveform created corresponding to the tape speed during special reproduction.

The present invention solves the above problems,
Good reproduction even during special reproduction by adding the drive pattern waveform for the electro-mechanical conversion element to follow the recording track in accordance with the reproduction speed of the magnetic tape during special reproduction, and the drive data for controlling track bending tracking An object of the present invention is to provide a tracking control device of a magnetic recording / reproducing device that obtains an output.

[0009]

According to the present invention, there is provided an apparatus for reproducing at least two parallel recording tracks simultaneously recorded on a magnetic recording medium with magnetic heads having different azimuth angles. At least two reproduction heads having different azimuth angles mounted on the electro-mechanical conversion element simultaneously scan the magnetic tape and detect a reproduction time difference of a specific signal included in each reproduced signal and reproduce reproduction time difference data. Reproducing time difference detecting means for outputting, reference value setting means for storing the reproducing time difference data when the reproducing output outputted from the magnetic head is maximized as tracking reference value data, and at N sample points per scan. The reproduction time difference data output from the reproduction time difference detecting means is output from the reference value setting means. Drive data calculating means for generating drive data for driving the electro-mechanical conversion element so as to match the king reference value data; FG signals output from the capstan motor and control signals recorded on the magnetic tape Pattern generating means for generating a drive pattern waveform for driving the electro-mechanical conversion element such that a reproducing head follows a recording track according to a reproducing speed of a magnetic tape based on the H-SW signal and a H-SW signal Addition means for adding the output of the drive data calculation means and the output of the drive pattern waveform generation means,
An electromechanical transducer driving means for applying a voltage corresponding to the output of the adding means to the electromechanical transducer.

A mode setting means for setting an operation mode of the system; and a tracking reference for outputting reproduction time difference data output from the reproduction time difference detection means at N sample points per scan from the reference value setting means. A drive data calculating unit for calculating and generating drive data for driving the electro-mechanical conversion element so as to match the value data; and a data storage unit for storing N points of the drive data per scan. Having.

[0011]

According to the above arrangement, by adding the drive pattern waveform for causing the reproducing head to follow the recording track in accordance with the tape speed and the driving data for performing the track bending follow-up control, the track bend follows during special playback. In addition, it is possible to perform tracking control capable of obtaining a good reproduction output even during special reproduction.

Further, when the reproduction output is not sufficiently obtained due to the vicinity of the head or the like during the special reproduction, the reproduction time difference data becomes unstable. Therefore, the drive data indicating the track bending pattern created during the normal reproduction is not changed during the special reproduction. By performing the output, it is possible to perform tracking control that can obtain a good reproduction output even when the reproduction time difference data is unstable.

[0013]

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

In FIG. 1, magnetic heads 101, 102
Have different azimuth angles and constitute a pair head,
It is mounted on the piezoelectric element 103. 104, 105
Reference numeral denotes an amplifier circuit for amplifying a reproduction signal output from the magnetic heads 101 and 102, and reference numeral 106 denotes a reproduction signal processing circuit for processing the reproduction signal. H-SYNC (A), H-SYNC reproduced by
(B) is output. The output horizontal synchronization signal H-SYN
C (A) and H-SYNC (B) are reproduction time difference detection circuits 1
08 is input. The reproduction time difference detection circuit 108 detects a reproduction time difference between the horizontal synchronization signals H-SYNC (A) and H-SYNC (B) and outputs reproduction time difference data. The reproduction time difference data output from the reproduction time difference detection circuit 108 is supplied to the drive data calculation circuit 109 and the reference value setting circuit 110.
Is input to In the reference value setting circuit 110, the magnetic head 1
01, when the reproduction signal level outputted from the reproduction head 101 is the maximum, that is, when the reproduction heads 101 and 102 reproduce and scan the on-track position, the reproduction time difference data output from the time difference detection circuit 108 is stored. Set and output as tracking reference value. The tracking reference value set by the reference value setting circuit 108 is held at that value until an editing point or an unrecorded portion is reproduced.
Reference numeral 109 denotes the piezoelectric element 1 at N sample points (N is an integer) per scan so that the reproduction time difference data output from the reproduction time difference detection circuit 108 matches the tracking reference value output from the reference value setting circuit 110.
The drive data arithmetic circuit 109 generates drive data for driving the drive data 03. The drive data arithmetic circuit 109 corrects the correction data "+" at N sample points per scan so that the reproduction time difference data matches the tracking reference value.
C "," 0 "," -C "(C> 0), and adds the created correction data to the drive data of the same reproducing head one scan before.If the reproduction time difference data is equal to the tracking reference value, Correction data "0" is created, and if different, correction data "+ C", "-C"(C>
0) is created and added to the drive data. Reference numeral 116 denotes a capstan motor, which outputs an FG signal when the capstan motor 116 rotates.
12 is input. A control head 117 reproduces a control signal recorded on the magnetic tape. A control signal output from the control head 117 is input to the waveform shaping circuit 113. Reference numeral 111 denotes an FG signal and a control signal whose waveforms have been shaped by the waveform shaping circuits 112 and 113 and H-
Piezo piezoelectric element 10 corresponding to tape speed from SW signal
3 is a drive pattern waveform generation circuit that generates a drive pattern waveform for displacing the drive pattern 3. Reference numeral 114 denotes an addition circuit for adding the drive data output from the drive data calculation circuit 109 and the drive pattern waveform output from the drive pattern waveform generation circuit 111. Reference numeral 115 denotes a voltage corresponding to the output of the adding circuit 114,
03 is an electro-mechanical conversion element drive circuit for applying the voltage to the element 03.

FIG. 2 is a block diagram of the drive pattern waveform generation circuit 111 according to the first embodiment of the present invention.

In FIG. 2, a terminal 201 receives a waveform-shaped control signal, and a terminal 202 receives a waveform-shaped FG signal. 206 counts based on the FG signal input from the terminal 202,
This is an FG counter circuit that resets the counter by a control signal input from the FG. A reference clock equal to the period of the FG signal at the time of normal reproduction is input from a terminal 204, 205 is a correction counter circuit that counts with a reference clock input from a terminal 204 and resets a counter by a control signal input from a terminal 201. is there. A subtraction circuit 208 subtracts the FG counter value output from the FG counter circuit 206 from the correction counter value output from the correction counter circuit 205. 20
Reference numeral 7 denotes a preset value setting circuit that detects the output value of the subtraction circuit 208 based on the H-SW signal input from the terminal 203 and sets the preset value of the FG counter circuit 206 according to the detected value.

In FIG. 2, the drive pattern waveform generation circuit 111 outputs 0 [V] during normal reproduction, and when the tape speed changes based on normal reproduction, the difference from the tape speed during normal reproduction is obtained. A drive pattern waveform having a corresponding slope is output. That is, the greater the difference from the tape speed during normal reproduction, the greater the slope of the drive pattern waveform. When the tape speed is higher than the tape speed at the time of normal reproduction, a drive pattern waveform having a slope in the + direction is output. The inclination of the drive pattern waveform makes it possible to follow the recording track of the reproducing head according to the tape speed.

FIG. 3 is an operation waveform diagram for explaining the operation of the first embodiment of the present invention. In FIG. 3, (a) is a REF 30 Hz reference signal. (B) is an H-SW signal indicating the scanning position of the reproducing head. (C) is a drive voltage applied to the piezoelectric element 103. (D) is a reproduction output output from the reproduction head. (E) is drive data which is an output of the drive data operation circuit 109. (F) is a drive pattern waveform output from the drive pattern waveform generation circuit 111. (G) is a control signal to be reproduced. In the figure, the tape speed is 1
This shows the operation when the reproduction is performed in the forward direction at the half speed, and point D is a point at which the preset value of the FG counter is changed. CH0 and CH1 are 1 on each other on the rotating cylinder.
This figure shows a reproducing head mounted on a piezo-electric element placed at an angle of 80 °, and shows an operation of only CH1.

In FIG. 3, the FG1 signal is counted by the drive pattern waveform generation circuit 111 when the tape speed is 1/2 speed, and as shown in FIG. 3F, at the falling of the control signal in FIG. By resetting and changing the preset value of the FG counter circuit 208 at point D, a drive pattern waveform is output as shown in FIG. At the same time, in the section 1, the drive data calculation circuit 109 changes the reproduction time difference data to N per scan so as to match the tracking reference value as shown in FIG.
Drive data is created and output at sample points at points (N is an integer). The output drive pattern waveform and drive data are added by the adder circuit 114, and the drive voltage shown in section 2 of FIG. As a result, the reproduced output output from the reproducing head is as shown in FIG. In the section 2, the drive data calculation circuit 109 creates drive data again so that the reproduction time difference data coincides with the tracking reference value ((e) in the figure), adds the drive data to the drive pattern waveform, and controls the driving of the piezoelectric element 103. . By performing the same processing in the section 3, the reproducing head can scan the on-track position.

As described above, according to the present embodiment, it is not assumed that the track is bent in accordance with the tape speed during the special reproduction.
By performing addition of the drive data for driving pattern waveform and track bend following control for following the track it has, also can play head scans the on-track position at the time of trick play, good reproduction output Can be performed.

FIG. 4 is a block diagram of a tracking control device of a magnetic recording / reproducing device according to a second embodiment of the present invention.

FIG. 4 differs from FIG. 1 in that a mode setting circuit 401 for setting the operation mode of the system, and that the reproduction time difference data is set so as to match the tracking reference value.
A drive data calculation circuit 402 including a drive data calculation unit for calculating and generating drive data at N sample points per scan (N is an integer) and a data storage unit for storing drive data at N points per scan is provided. is there. FIG.
, The mode setting circuit 401 outputs a low-level mode signal when the operation mode of the system is the normal reproduction mode, and outputs a high-level mode signal when the operation mode is other than the normal reproduction mode. When the mode signal is at the LOW level, that is, in the normal reproduction mode, the reproduction time difference detection circuit 108
Drive data is created at N sample points per scan so that the playback time difference data output from the controller coincides with the tracking reference value, and the created drive data is stored in the data storage unit. And outputs the driving data stored therein. When the mode signal changes to the HIGH level, the drive data calculation unit of the drive data calculation circuit 402 stops the calculation of the drive data, and stores the drive data created immediately before the mode signal changes from the LOW level to the HIGH level in the data storage unit. Output from The output drive data is added to the drive pattern waveform by the addition circuit 114, and the electro-mechanical conversion element drive circuit 115 applies a drive voltage corresponding to the addition result to the electro-mechanical conversion element.

FIG. 5 is an operation waveform diagram for explaining the operation in the second embodiment of the present invention.

In FIG. 5, (a) is a REF 30 Hz reference signal. (B) is an H-SW signal indicating the scanning position of the reproducing head. (C) is a drive voltage applied to the piezoelectric element 103. (D) is a reproduction output output from the reproduction head. (E) is drive data which is an output of the drive data operation circuit 402. (F) is a drive pattern waveform output from the drive pattern waveform generation circuit 111. (G) is a mode signal output from the mode setting circuit 401. Section 1 in the drawing is in the normal playback mode, and section 2 shows the operation when the tape is played back in the forward direction in the half speed special playback mode. Point D is a point where the preset value of the FG counter is changed. CH0 and CH1 denote reproduction heads mounted on piezoelectric elements mounted on the rotary cylinder 180 ° opposite to each other, and indicate the operation of only CH1.

In the section 1 in FIG. 5, when the normal reproduction mode is set, the mode setting circuit 401 outputs a low-level mode signal as shown in FIG. Mode signal is L
At the OW level, the drive data calculation unit of the drive data calculation circuit 402 generates drive data at N sample points per scan so that the playback time difference data output from the playback time difference detection circuit 108 matches the tracking reference value. I do. The generated drive data is stored in the data storage unit, and the drive data generated one scan before the reproducing head is output from the data storage unit as shown in FIG. The drive data output from the drive data calculation circuit 402 is added to the drive pattern waveform shown in FIG. 9F, and the drive voltage shown in FIG. 9C is applied to the piezoelectric element 103. When the mode is changed from the normal reproduction mode to the half speed special reproduction mode, the mode signal output from the mode setting circuit 401 changes to the HIGH level as shown in section 2 of FIG. Mode signal is HIGH
When the level becomes the level, the drive data calculation circuit 402 stops the calculation of the drive data as shown in FIG. 11E, and the same reproduction created immediately before the mode signal changes from the LOW level to the HIGH level from the data storage unit. The drive data before one scan of the head is output. In the half speed special reproduction mode, the drive pattern waveform generation circuit 111 outputs a drive pattern waveform corresponding to the tape speed as shown in FIG. The output drive data and the drive pattern waveform are added by the adding circuit 114, and FIG.
A driving voltage corresponding to the addition result is applied to the piezoelectric element 103 as shown in FIG. By repeating this process, the reproducing head can perform tracking control capable of scanning the on-track position.

As described above, according to the present embodiment, the mode setting circuit 401 for setting the operation mode of the system.
A drive data calculation unit for calculating drive data at N sample points per scan so that the reproduction time difference data matches the tracking reference value, and a data storage unit for storing N points of drive data per scan. A drive data calculation circuit 402 is provided. When the operation mode is the normal reproduction mode, the drive data calculation section of the drive data calculation circuit 402 drives the reproduction time difference data at N sample points per scan so as to match the tracking reference value. When the operation mode becomes a mode other than the normal reproduction mode, the calculation of the drive data is stopped, and the drive data generated in the normal reproduction mode is transferred to the drive data calculation circuit 4.
By outputting the data from the data storage unit No. 02, it is possible to perform tracking control capable of obtaining a good reproduction output even when the reproduction time difference data cannot be obtained due to the influence of the contact with the head in the special reproduction mode.

[0027]

As described above, according to the present invention, by controlling the driving of the piezoelectric element by adding the drive data for performing the track bending follow-up control and the drive pattern waveform for following the recording track according to the tape speed. , Can perform track bend following control in special playback mode,
It is possible to perform tracking control capable of obtaining a good reproduction output.

A mode setting circuit for setting an operation mode of the system; a drive data calculating section for generating drive data at N sample points per scan so that the reproduction time difference data matches the tracking reference value; A drive data operation circuit comprising a data storage unit for storing N points of drive data per scan is provided. In the mode setting circuit, in the normal reproduction mode, N points of samples per scan are set so that the reproduction time difference data matches the tracking reference value. In the mode other than the normal playback, the drive data created in the normal playback mode is output from the data storage unit so that the playback time difference data is unstable due to the head contact or the like in the special playback mode. Tracking control that can obtain good playback output even when Ukoto can.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of a drive pattern waveform generation circuit according to the embodiment;

FIG. 3 is an operation waveform diagram for explaining the operation of the embodiment.

FIG. 4 is a tracking control device for a magnetic recording / reproducing device according to a second embodiment of the present invention.

FIG. 5 is an operation waveform diagram for explaining the operation of the embodiment.

FIG. 6 is a schematic diagram for explaining a conventional azimuth time difference detection method and its waveform diagram.

[Description of Signs] 111 Drive pattern waveform generation circuit 114 Addition circuit 205 Correction counter circuit 206 FG counter circuit 207 Preset value setting circuit 401 Mode setting circuit 402 Drive data calculation circuit

Claims (2)

(57) [Claims] 1. An apparatus for reproducing at least two parallel recording tracks simultaneously recorded on a magnetic tape with magnetic heads having different azimuth angles during normal reproduction
The electric - using the reproduction time difference between specified signals transducer differ by at least two reproducing heads having azimuth angles mounted on are included in the reproduction signal reproduced by scanning the recording tracks <br/> above simultaneously To correct the bending of the recording track.
Wherein the so that electrical - driving data calculating means for creating and storing driving data for driving the transducer, special re
Playback head is Tiger according to the playback speed of the magnetic tape at the time of raw
Drive pattern waveform generating means for generating a drive pattern waveform for driving the electro-mechanical conversion element so as to follow a recording track that does not assume a magnetic curve,
The drive data stored in the drive data calculation means during the special reproduction.
Data and the data generated by the drive pattern waveform generation means.
Adding the live pattern waveform to the electro-mechanical conversion element
Tracking control apparatus Yu the <br/> magnetic recording and reproducing apparatus and an adding means for generating a waveform for driving the child. 2. The drive data calculation means according to claim 1, wherein said drive data calculation means comprises
Small azimuth angles with different azimuth angles
At least two reproducing heads simultaneously move on the recording track.
The reproduction of a specific signal included in each reproduced signal that has been scanned and reproduced
Reproduction detected from the raw time difference and output from the magnetic head
Tracking the playback time difference when the output is maximum
Set as reference value data, and N points per scan
The playback time difference at the sample point
The electric-mechanical so as to match the locking reference value data.
Create drive data to drive the conversion element
In addition, the drive pattern waveform generating means
FG signal output from the data and recorded on the magnetic tape
Drive signal based on the control signal and H-SW signal
2. The tracking control device for a magnetic recording / reproducing apparatus according to claim 1, wherein a turn waveform is generated .