JP2533258B2 - 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 magnetic recording / reproducing apparatus (hereinafter referred to as VTR), and in particular, in a VTR having an electro-mechanical conversion element for driving a head, frame editing such as time-lapse editing is performed. The present invention also relates to a drive system of an electro-mechanical conversion element that realizes stable tracking control even with a tape.

[0002]

2. Description of the Related Art In order to perform tracking control using an electro-mechanical conversion element such as a piezoelectric element, a detection signal obtained by detecting the amplitude of a reproduction signal is compared for each scanning track, and detection is performed based on the comparison result. A method has been proposed in which the electro-mechanical conversion element mounted with a magnetic head is driven in the track width direction so as to maximize the signal. In this method, the electro-mechanical conversion element is always driven in a direction in which the detection signal becomes large.

A conventional tracking control method using a detection signal will be described below. FIG. 4 is a diagram showing an Ach magnetic head and a recording track locus, and FIG. 5 is a diagram showing a change in envelope detection level when the magnetic head is driven as in FIG. When the magnetic head is moved in the track width direction as indicated by the arrow in FIG. 4, the detection signal level repeatedly increases and decreases. At that time, the envelope detection level changes into a mountain-shaped level change as shown in FIG. 5, and even if there is a difference in sensitivity between the recording and reproducing magnetic heads, the peak level of the mountain becomes constant every other track.

On the premise of this, the following envelope tracking control has been conventionally performed. That is, in the envelope tracking control using the detection signal, the electro-mechanical conversion element equipped with the magnetic head is driven in a certain direction, and the level of the detection signal after driving is compared with the level of the detection signal after driving. If the level of the detection signal increases, the electro-mechanical conversion element is driven in the same direction next time, and if it decreases, the electro-mechanical conversion element is driven in the opposite direction. However, if the level of the detection signal changes due to factors other than the movement of the magnetic head,
There is a possibility that the moving direction of the magnetic head will be wrong. For example, when frame editing such as time-lapse editing or compatible editing is performed, the track widths of the first and last tracks of the frame become narrow, and the peak level of the mountain may fluctuate. As a result, the driving direction is wrong at the first and last tracks of the frame,
There is a drawback that tracking control becomes unstable. Here, a specific description will be given with reference to FIGS.

FIG. 6 is a main block diagram of a magnetic recording / reproducing apparatus. The magnetic heads 1, 2, 3 and 4 are mounted on the electromechanical conversion elements 5 and 6, respectively, and are driven in the track width direction. The magnetic heads 1, 2 and 3, 4 are arranged on the cylinder so as to face each other by about 180 degrees, and switch every half rotation of the cylinder. The amplifiers 9, 10 and 11, 12 amplify the signals reproduced by the magnetic heads 1, 2 and 3, 4. The detection circuits 13, 14 and 15, 16 detect the signals amplified by the amplifiers 9, 10 or 11, 12, respectively. The signals detected by the detection circuits 13 and 14 are added by the adder 17, and the signals detected by the detection circuits 15 and 16 are added by the adder 18, respectively, and the A / D converter is added.
Sent on 19 and 20. A / D converter 19 and 20
The D-converted data is taken into the microcomputer 21. The microcomputer 21 imports the embedded data into H.264. The direction of the drive data is determined by making a comparison for each SW cycle, and is sent to the D / A converters 22 and 23 as the drive data of each channel. D / A converter 22
And 23 perform D / A conversion of the drive data sent from the microcomputer 21, and the electro-mechanical conversion element drive circuit 7
And 8 The electro-mechanical conversion element drive circuits 7 and 8 drive the electro-mechanical conversion elements 5 and 6 based on the D / A converted drive data.

Next, the case where the normal recording track is made to follow the envelope will be described in detail with reference to FIGS. 11, 12, 13, and 14. FIG. 11 is a flowchart showing the flow of processing of envelope tracking control in the conventional example. Step 1100
Performs initial value setting of various parameters and rising edge interrupt setting. Performs edge interrupt processing for rising or falling of the SW signal. Processing is divided into Ach at the rising edge and Bch at the falling edge. In steps 1102 to 1104, the process of loading the first value of the envelope detection level into the memory MA is performed. In step 1105, the drive amount S1 for changing the drive amount NA from the previous drive amount NA
Is added and set, and in step 1106, the value of the memory NA is output to DA0. In step 1107, the envelope detection level after driving the head is stored in the memory MB.
The process of importing into. In step 1108, the envelope detection level MA before driving and the envelope detection level MB after driving
Is comparing with. If the envelope detection level after driving is high, the parameter α in the driving direction in step 1109
Is set to α = 1, and when the envelope detection level after driving is small, the parameter α in the driving direction is set to α = −1 in step 1110. In step 1111, the driving amount S1 changed by the driving direction parameter α is set as S1 = S1 * α. In step 1112, the contents of the memory MB are stored in the memory MA for the next comparison. In step 1113, the edge designation of the interrupt is set to fall for the processing of Bch, and the process returns to step 1101.

Exactly the same way, Bch processing is performed as follows. Since the interrupt edge setting is falling, step 11
From 01, proceed to step 1114. Step 1114 to Step 11
In 16, the process of loading the value of the first envelope detection into the memory MC is performed. In step 1117, the drive amount NB is set by adding the drive amount S2 that changes the previous drive amount NB, and in step 1118, the value of the memory NB is output to DA1. In step 1119, a process of loading the envelope detection level after driving the head into the memory MD is performed. In step 1120, the envelope detection level MC before driving and the envelope detection level MD after driving are compared. If the envelope detection level after driving is high, step
If the parameter β in the driving direction is set to β = 1 by 1121 and the envelope detection level after driving is low, step
The parameter β in the direction driven by 1122 is set to β = −1,
Each is set. In step 1123, the driving amount S2 changed by the driving direction parameter β is S2 = S2 *
Set as β. In step 1124, the contents of the memory MD are stored in the memory MC for the next comparison. Step
At 1125, the edge designation of the interrupt is set to rising for the processing of Ach, and the process returns to step 1101. The envelope tracking control is performed by repeatedly performing the steps described above.

FIG. 12 shows the change in the driving amount of Ach and the change in the envelope detection level of Ach in the conventional example. It is a figure shown in time series for every SW cycle. The solid line shows the case where the normal recording track state is followed by the envelope, and the dotted line shows the case where the frame-edited recording track is envelope-followed. FIG. 13 is a diagram showing the behavior of the magnetic head when the normal recording track state in the conventional example is tracked with one track as an index, and FIG. 14 is the drive amount when the track after frame editing in the conventional example is tracked with the envelope. FIG. 6 is a diagram showing behavior of the envelope detection level with one track as an index.
13 and 14, the horizontal axis represents the drive amount of Ach and the vertical axis represents the envelope detection level of Ach.

In FIG. 12, in the first step, the drive amount D
In 1, the embedding detection level E1 is taken in (point A in FIG. 13),
In the second step, the drive amount is increased by one level and the envelope detection level E2 is taken in as D2 (point B in FIG. 13). When the envelope detection levels are compared (E2-E1)> 0, the direction parameter α = 1 and the driving direction does not change, so the driving amount in the third step is increased by one level from D2 to D3 (FIG. 13). Point C). Similarly, the fourth step (point D in FIG. 13) and the fifth step (point E in FIG. 13) are also processed, and the drive amount in the fifth step is D5, but the comparison of the envelope detection levels at that time is (E3 -E4) <0. Therefore, since the direction parameter α = −1 and the driving direction changes, the driving amount at the sixth step (point D in FIG. 13) becomes smaller than D5 and becomes D4, and the comparison of the envelope detection levels is (E4-E3)> It becomes 0. (E4-E3)
From> 0, the direction parameter α becomes α = 1, and the driving direction does not change, so the driving amount at the seventh step (point C in FIG. 13) decreases from D4 to D3. At this time, the comparison of the envelope detection levels becomes (E3−E4) <0, and the drive amount in the eighth step (point D in FIG. 13) increases from D3 to D4.
Similarly, the processing is performed according to the flowchart of FIG. 11, and the ninth step (point E in FIG. 13) and the tenth step (Fig.
The changes are the 13th step (D point), the 11th step (C point in FIG. 13), the 12th step (D point in FIG. 13), and the 13th step (E point in FIG. 13).

[0010]

However, in the above-described conventional configuration, when the envelope detection level of the track before or after the edit point is lowered during frame editing, the envelope detection level is irrelevant regardless of the drive of the magnetic head. Changes, and the envelope tracking control becomes unstable. For example, in the case of segment recording, the track locus when edited for each frame is as shown in FIG. FIG. 7 shows a track locus in the case of 2 tracks / segment and 6 segments / frame. In FIG. 7, 70
Reference numeral 1 is a magnetic tape, 702 is a segment number, 703 is a frame number, and 704, 705 and 706 are joints for frame editing. At the joint, there are track bends and tracking shifts due to device compatibility, and unerased or scraped off recorded tracks may occur, so a flying erase head may be attached.

In this case, the flying erase is operated in advance of the recording magnetic head in order to eliminate the unerased portion when editing. FIG. 8 shows the positional relationship between the flying erase head 801 and the recording magnetic head 802 at the start point and the recording track generation process in the case of performing the insert edit in the frame number 2. Flying erase head
The 801 is a recording magnetic head, taking into consideration the compatibility of edit points.
Wider than 802. Therefore, when the flying erase head 801 is operated ahead of the recording magnetic head 802, the final track (frame number: 1 and segment number: 5) of the frame immediately before the editing point is deleted.

Similarly, FIG. 9A, FIG. 9B, and FIG. 9C show track trajectories when insert editing is performed on frame number 3 after frame number 2. Figure 9 (a) shows frame number 2
Indicates that the track (frame number: 1, segment number: 5) immediately before editing is deleted due to the insertion of. FIG. 9B shows that the track of the segment number 5 of the frame number 2 is deleted because the frame number 2 is also insert-edited but the frame number 3 is continuously edited. In FIG. 9 (c), since the frame editing is completed at frame number 3, the first track of the next frame (frame number: 4, segment number:
0) is deleted.

As a result, FIG. 10 shows the envelope detection output when the track edited as described above is fixedly scanned without the envelope tracking control of the magnetic head. FIG.
In, the horizontal axis is the segment number and frame number,
The vertical axis represents the envelope detection level. Track with frame number 1 and segment number 5, track with frame number 2 and segment number 5, and frame number 4
Then, the level of the envelope detection signal of the track of segment number 0 becomes R2, which is lower than the normal level R1.

Next, referring to FIG. 12, the following of the envelope when the envelope detection level captured in the eighth step is low as described above will be described. 7th step (point C in Figure 14)
In the 8th step (Fig.
When the driving amount is set to D4 at point 14 of 14), the envelope detection level becomes E5. At this time, the comparison of the envelope detection levels becomes (E5−E3) <0, the direction parameter α = −1, and the driving direction changes, so the ninth step (see FIG.
The driving amount at point 14) is D3, and the envelope detection level is E3. At this time, the comparison of the envelope detection levels is (E3-E
5)> 0, the direction parameter α = 1 and the driving direction does not change, so the driving amount in the 10th step (point B in FIG. 14) is D2, and the envelope detection level is E2. At this time, the comparison of the envelope detection levels is (E2−E3) <0, the direction parameter α = −1, and the driving direction changes, so the driving amount in the 11th step (point C in FIG. 14) is D.
3, the envelope detection level is E3. Similarly, 12th step (point D in FIG. 14) and 13th step (E in FIG. 14)
Do the processing of point). As a result, the tracking behavior of the envelope
As shown by the dotted line 12, there is a problem that the embedding detection level at the 10th step drops to a level lower than usual due to the reduction of the embedding detection level at the 8th step.

The present invention solves the above-mentioned conventional problem. By performing envelope follow-up control without using the envelope detection level of the first track and the last track of a frame, the first track of the frame or An object of the present invention is to provide a magnetic recording / reproducing apparatus capable of realizing stable envelope tracking control even if the envelope detection level of the final track is lowered.

[0016]

In order to solve this problem, in the magnetic recording / reproducing apparatus of the present invention, each track formed of a plurality of track groups each having one frame of three tracks or more is placed on an electro-mechanical conversion element. In a structure for reproducing by a mounted magnetic head, a means for detecting a signal reproduced by the magnetic head mounted on the electro-mechanical conversion element, a means for comparing the detected signal level for each track, and the comparison The electromechanical conversion element is driven according to the output of the means to perform tracking control, and the electromechanical conversion is performed without using the detection signals of the first and last tracks of the frame in the detection signal. The configuration is such that the drive amount of the element is maintained and the envelope tracking control is performed.

[0017]

According to the present invention, with the above configuration, the envelope detection level is not lowered regardless of the drive of the magnetic head by performing the envelope tracking control without using the envelope detection level in the first and last tracks of the frame. Therefore, the envelope tracking control is performed without being disturbed.

[0018]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a flow chart showing an algorithm for envelope tracking control in a magnetic recording / reproducing apparatus according to an embodiment of the present invention. In this embodiment, 6
A description will be given with the configuration of segment / 1 frame.

In FIG. 1, step 100 sets initial values of various parameters and rising edge interrupt setting, and step 101 sets H. Performs edge interrupt processing for rising or falling of the SW signal. Ach at rising edge, Bc at falling edge
It is divided into the processing of h. In step 102, when the first and last tracks of the frame, that is, segment numbers 0 and 5, the process returns to step 101 and the magnetic head is not driven.
If the segment number is other than 0 or 5, the process proceeds to step 103. In steps 103 to 105, the process of loading the first envelope detection level value into the memory MA is performed. In step 106, the drive amount NA is changed to the previous drive amount NA.
And the drive amount S1 to be changed are added and set, and step 10
At 7, the process of outputting the value of the memory NA to DA0 is performed. In step 108, the envelope detection level after driving the head is loaded into the memory MB. In step 109, the envelope detection level MA before driving and the envelope detection level MB after driving are compared. When the envelope detection level after driving is large, the parameter α in the driving direction in step 110 is set to α = 1, and when the envelope detection level after driving is small, the parameter α in the driving direction in step 111 is set to α = -1. , Are set respectively.
In step 112, the driving amount S1 changed by the driving direction parameter α is set as S1 = S1 * a. In step 113, the contents of the memory MB are stored in the memory MA for the next comparison. In step 114, the edge designation of the interrupt is set to fall for the processing of Bch, and the process returns to step 101.

Exactly the same way, Bch processing is performed as follows. Since the interrupt edge setting is falling, step 10
Go from 1 to step 115. In step 115, when the first and last tracks of the frame, that is, segment numbers 0 and 5, the process returns to step 101 and the magnetic head is not driven. Steps other than segment numbers 0 and 5
Continue to 116. In steps 116 to 118, the process of loading the first value of the envelope detection level into the memory MC is performed. In step 119, the drive amount NB is set by adding the drive amount S2 that changes the previous drive amount NB, and in step 120, the value of the memory NB is output to DA1. In step 121, the envelope detection level after driving the head is loaded into the memory MD. In step 122, the envelope detection level MC before driving and the envelope detection level MD after driving are compared. If the envelope detection level after driving is large, the driving direction parameter β is set to β = 1 in step 123. If the embedded detection level after driving is small, the driving direction parameter β is set to β = −1. , Are set respectively. In step 125, the driving amount S2 changed by the driving direction parameter β is set as S2 = S2 * β. In step 126, the contents of the memory MD are stored in the memory MC for the next comparison. In step 127, the edge designation of the interrupt is set to rising for the processing of Ach, and the process returns to step 101. By repeatedly performing the steps described above, the envelope tracking is performed.

Next, a description will be given of a case where the recording track, which is actually frame-edited, is made to follow the envelope with reference to FIGS. 2 and 3. FIG. 2 shows the change in the driving amount of Ach and the change in the envelope detection level when the frame-edited recording track is subjected to the envelope tracking control in the present embodiment. It is a figure shown in time series for every SW cycle. FIG. 3 is a diagram showing the behavior of the Ach magnetic head when the frame-edited recording track is subjected to envelope tracking control in the present embodiment, with one track as an index. 2 and 3, the horizontal axis represents the Ach drive amount, and the vertical axis represents the Ach envelope detection level.

In FIG. 2, in the first step, the drive amount D
1, the embedding detection level E1 is taken in (point A in FIG. 3),
In the second step (point A in FIG. 3), since the segment number is 0, the process is skipped in step 102 in FIG.
It remains 1.

In the third step (point B in FIG. 3), the processing of the second step is skipped, so the drive amount is increased by 1 level to D2, and the envelope detection level E2 is fetched. When the embedding detection levels are compared, (E2-E1)> 0, so
The direction parameter α = 1 and the driving direction does not change.

Since the segment number in the fourth step (point C in FIG. 3) is other than 0 and 5, the process proceeds to step 103 and subsequent steps in step 102 in FIG. The driving amount in the fourth step is increased by one level from D2 to D3 from the direction parameter α = 1.
(Point C in FIG. 3). When the envelope detection levels are compared (E3−E2)> 0, the direction parameter α = 1
The driving direction does not change.

In the fifth step (point C in FIG. 3), since the segment number is 0, the process is skipped in step 102 in FIG. 1 and the drive amount remains D3. 6th step (D in FIG. 3)
(Point) indicates that the segment number is other than 0 and 5, the process proceeds to step 103 onward in step 102 of FIG. 1 and the process of the fifth step is skipped, so the direction parameter α of the fourth step becomes α = 1, and the driving direction Does not change, the drive amount in the 6th step is increased by 1 level from D3 to D4.
(Point D in FIG. 3). When the envelope detection levels are compared (E4-E3)> 0, the direction parameter α = 1
The driving direction does not change.

Since the segment number in the seventh step (point E in FIG. 3) is other than 0 and 5, the process proceeds to step 103 and the subsequent steps in step 102 in FIG. The driving amount in the seventh step is increased by one level from D4 to D5 from the direction parameter α = 1.
(Point E in FIG. 3). When the envelope detection levels are compared (E3−E4) <0, the direction parameter α = −
It becomes 1 and the driving direction changes.

In the eighth step (point E in FIG. 3), since the segment number is 0, the process is skipped in step 102 in FIG. 1 and the drive amount remains D5. Step 9 (D in FIG. 3
Since the segment number is other than 0 and 5, the process proceeds from step 103 to step 103 onward in FIG. 1 and the process of the eighth step is skipped. Therefore, the envelope detection level E5 of segment number 0 is not affected. The direction parameter α in the seventh step becomes α = −1, and the driving direction changes. The driving amount in the ninth step is D4, which is one level less than D5 from the direction parameter α = −1 (D in FIG. 3).
point). Comparing the envelope detection levels (E4-E3)>
Since it becomes 0, the direction parameter α = 1 and the driving direction does not change.

Since the segment number is other than 0 and 5 in the 10th step (point C in FIG. 3), the process proceeds from step 103 to step 103 onward in FIG. The driving amount of the 10th step is decreased by one level from D4 to D3 from the direction parameter α = 1.
(Point C in FIG. 3). When the envelope detection levels are compared (E3−E4) <0, the direction parameter α = −
It becomes 1 and the driving direction changes.

In the eleventh step (point C in FIG. 3), since the segment number is 0, the process is skipped in step 102 in FIG. 1 and the drive amount remains D3. 12th step (D in FIG. 3)
(Point) indicates that the segment number is other than 0 and 5, the process proceeds to step 103 and subsequent steps in FIG. 1 and the process of the 11th step is skipped. Changes. 12th
The driving amount of the step is increased by one level from D3 and becomes D4 (point D in FIG. 3). Comparing the envelope detection levels (E
Since 4-E3)> 0, the direction parameter α = 1 and the driving direction does not change.

Since the segment number is other than 0 and 5 in the 13th step (point E in FIG. 3), the process proceeds from step 103 to step 103 onward in FIG. The driving amount in the 13th step is increased by one level from D4 to D5 from the direction parameter α = 1.
(Point E in FIG. 3).

As a result, the envelope detection level does not become lower than E3 except for the track of frame number 2 and segment number 0. Therefore, even if the envelope detection level decreases in the recording tracks immediately before and after the edit point, the envelope tracking control is not adversely affected.

[0032]

As described above, according to the present invention, even if the frame detection level is reduced at the first and last recording tracks of a frame by performing frame editing using the flying erase head, By performing the envelope tracking control without using the envelope detection level in the last recording track, a good image can be obtained even in the recording track in which frame editing is performed.

[Brief description of drawings]

FIG. 1 is a flowchart showing an algorithm of envelope tracking control in a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a change in the drive amount of Ach and a change in the envelope detection level when the recording track having the frame edited is subjected to the envelope tracking control in the magnetic recording / reproducing apparatus of the embodiment of the present invention. It is a figure shown in time series for every SW cycle.

FIG. 3 is a diagram showing the behavior of an Ach magnetic head when a frame-edited recording track is subjected to envelope tracking control in the magnetic recording / reproducing apparatus according to an embodiment of the present invention, with one track as an index.

FIG. 4 is a diagram showing a direction in which a magnetic head is driven in a magnetic recording / reproducing apparatus.

FIG. 5 is a diagram showing changes in the envelope detection level when the magnetic head is driven in the track width direction in the magnetic recording / reproducing apparatus.

FIG. 6 is a main block diagram of a magnetic recording / reproducing apparatus.

FIG. 7 is a diagram showing track trajectories in the case of 2 tracks / segment and 6 segments / frame in the magnetic recording / reproducing apparatus.

FIG. 8 is a diagram showing a positional relationship between a flying erase head and a recording magnetic head at a start point and a recording track generation process in the case of performing insert editing in frame number 2.

FIG. 9 is a diagram showing a track trajectory when insert editing is performed on frame number 3 subsequent to frame number 2.

FIG. 10 is a diagram showing an envelope detection output when an edited track is scanned without performing the envelope tracking control of the magnetic head.

FIG. 11 is a flowchart showing a processing flow of envelope tracking control in a conventional example of a magnetic recording / reproducing apparatus.

FIG. 12 shows a change in the drive amount of Ach and a change in the envelope detection level of Ach in the conventional example of the magnetic recording / reproducing apparatus. It is the figure shown in time series for every SW cycle.

FIG. 13 is a diagram showing the behavior of the drive amount and the envelope detection level when performing the envelope follow-up control on the normal recording track in the conventional example of the magnetic recording / reproducing device, with one track as an index.

FIG. 14 is a diagram showing the behavior of the drive amount and the envelope detection level when the track following frame editing in the conventional example of the magnetic recording / reproducing apparatus is subjected to envelope tracking control, with one track as an index.

[Explanation of symbols]

 1,2,3,4 Magnetic head 5,6 Electro-mechanical conversion element 7,8 Electro-mechanical conversion element drive circuit 9,10,11,12 Amplifier 13,14,15,16 Detection circuit 17,18 Adder 19 , 20 A / D converter 21 Microcomputer 22,23 D / A converter 701 Magnetic tape 702 Segment number 703 Frame number 704, 705, 706 Frame editing joint 801 Flying erase head 802 Recording magnetic head

Claims (1)

(57) [Claims] 1. A magnetic recording / reproducing apparatus for reproducing each track constituted by a group of a plurality of tracks of which one frame is three tracks or more by a magnetic head mounted on the electro-mechanical conversion element, wherein the electro-mechanical conversion element is used. Means for detecting a signal reproduced by a magnetic head mounted on the means, means for comparing the detected signal level for each track, and driving the electro-mechanical conversion element according to the output of the comparing means, Tracking control means for performing tracking control,
A magnetic recording / reproducing apparatus comprising: means for maintaining the drive amount of the electromechanical conversion element without using the detection signals of the first and last tracks of the frame in the detection signal.