JPH10261202A - Magnetic recording method and rotary drum device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform sure editing even in a magnetic recording format having a narrow average track pitch so as to perform high recording density magnetic recording by collecting a plurality of helical tracks as one group and widening the helical track widths of both ends. SOLUTION: A helical track group 3 is composed of four helical tracks 9, 5, 6 and 10, the ITI (i), audio (a), video (v) and subcode (s) of the respective helical tracks 9, 5, 6 and 10 are arrayed horizontally, and this helical track group 3 is made repeatedly connected. The widths of the helical tracks 9 and 10 are widened more than those of the helical tracks 5 and 6 by an amount equal to an error made by the influence of an editing time. Thus, two kinds of azimuth angles cross each other, at least not two but a plurality of adjacent helical tracks are collected as one group, the helical tracks of both ends of the helical track of this group are widened and the editing points of the helical tracks are arranged among the helical track groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording method for defining a helical track to be recorded on a magnetic tape of a magnetic recording / reproducing apparatus having a rotating drum for recording helically on a magnetic tape, and recording / reproducing by the magnetic recording method. The present invention relates to a rotary drum device having a magnetic head arrangement.

[0002]

2. Description of the Related Art In recent years, as VTRs have been digitized and compression methods have been advanced, further miniaturization and higher-density recording have been demanded. There is a demand for the promotion of track pitch and the improvement of recording density.

FIG. 10 shows an NTSC that is currently in practical use.
It is a top view showing the magnetic tape pattern of DV format of 525 scanning lines and 30 frames in an area. FIG.
At 0, 1 is a magnetic tape, 11 and 12 are first and second
The helical tracks 13 and 14 are a group of five helical tracks which are a group of channels Ch1 and Ch2 having different audios, and Ch1 and Ch2 are audios 1 and 2.

In a tape pattern defined as a DV format, one frame is composed of ten first and second helical tracks 11 and 12 having the same helical track width in which the azimuth angles are alternately opposite to each other. The first five lines and the last five lines in one frame form a group. First and second helical trucks 11, 1
At the top of 2, ITI for servo control (omitted in the figure),
Next, there are an audio area Audio that forms one channel with five helical tracks, a video Video that makes up one frame with ten helical tracks, and a subcode (omitted in the drawing). When editing audio, video, and subcode in the DV format, the editing point is located between the groups 13 and 14 or between the groups 14 and 13 of the audio channels with respect to audio.
There are 10 video and subcodes, and there are edit points between a set of frames. The ITI, audio, video, and subcode are each arranged at a predetermined height from the lower end of the tape.

[0005] FIG. 11 is a diagram showing the status of practical use 3
FIG. 3 is a plan view showing a magnetic recording pattern of a 0-frame HD format DV format. 15, 16, 17, 18,
Reference numeral 19 denotes a group of five helical tracks 11 and 12 for each audio channel.

In FIG. 11, one frame is composed of twenty first and second helical tracks 11 and 12. The edit points of the magnetic recording pattern shown in FIG. 11 are between audio channels and between video frames.

FIG. 12 is a schematic plan view of a rotary head drum for recording and reproducing the magnetic recording patterns shown in FIGS. In FIG. 12, 31 is a rotating drum, 32 is a rotating direction of the rotating drum 31, 39, 40, 45, and 46 are rotation erasing heads, 41, 42, 47, and 48 are recording heads, and 37, 38, 43, and 44 are reproductions. Head.

The rotating drum 31 records two pairs of the helical tracks 11 and 12 in one rotation. The helical track 11 is recorded by the recording heads 41 and 47, and the helical track 12 is recorded by the recording heads 42 and 48. At the time of editing, the helical track 11 is rotated by the rotary erase heads 39 and 45.
Of the helical track 12 with the rotary erase heads 40 and 46
Are alternately deleted. Thereafter, the recording heads 41, 42, 4
Helical tracks 11 and 12 are recorded by 7, 48. The reproducing heads 37, 38, 43, and 44 scan the recorded helical tracks 11, 12, and take out signals.

A phenomenon at an editing point in a head drum with a rotary erasing head will be described with reference to FIG. FIG. 13 (a)
Is a diagram illustrating track scraping at the edit point,
In the figure, reference numeral 51 denotes track scraping. Helical truck 1
The recording head 4 is recorded at the mark where the rotary erasing head 40 erases the recording head 4.
2 newly records the helical track 12.

If the track scraping 51 is δS,

[0011]

(Equation 1)

## EQU1 ## Here, δSe is track scraping caused by the wide rotation erasing head 40, δS1 is track scraping caused by track linearity error due to compatibility or off-track of servo, and δSa is track scraping caused by head arrangement and width error. is there. Due to these error generation factors, track scraping 51 occurs at the edit point, and the helical track 11 becomes thinner by the track scraping 51.

On the other hand, FIG. 13B is a diagram for explaining the remaining track of the same azimuth at the editing point.
2 is the remaining track. If the remaining track 52 is δR,

[0014]

(Equation 2)

## EQU1 ## Here, δSe is track scraping caused by the rotary erase head 40, δRl is track remaining due to track linearity error and servo off-track due to compatibility, and δRa is track remaining due to head positioning error and width error due to compatibility. is there. If a track residue of the same azimuth is generated, the signal of the track residue is mixed with a normal signal, thereby causing signal deterioration.

Next, the phenomenon at the editing point of the overwrite method will be described with reference to FIG. FIG. 14A is a diagram for explaining track shaving at an editing point, and the numbers in the figure are the same as those in FIG. The recording head 42 newly records the helical track 12 on the helical track 12.

If the track scraping 51 is δS,

[0018]

(Equation 3)

## EQU1 ## For this reason, track scraping 51 occurs at the edit point, and the helical track 11 becomes thinner by the track scraping 51.

On the other hand, FIG. 14B is a diagram for explaining the remaining track at the edit point. Track remaining 52 to δ
If R

[0021]

(Equation 4)

## EQU1 ## The rest of the track is reproduced as the same azimuth, causing signal deterioration.

The width of the helical tracks 11 and 12 is set in such a range that a normal signal can be obtained even if the track scraping 51 or the track remaining 52 occurs even in the rotation erasing method and the overwriting method. As a result, 100% reliability of the editing work is guaranteed.

These errors occur in the helical tracks 11, 12 in contact with the helical track groups 13, 14, 15, 16, 17, 18, and the helical tracks inside the helical track group are not affected. The helical track inside the helical track group is affected only by the track shaving δSa and the track remaining δRa caused by the head placement error and the width error.

On the other hand, the helical track width of the editing point is set within a range where no error occurs in the signal in the worst case even in consideration of editing. That is, the helical track width B is

[0026]

(Equation 5)

Various parameters are set so that Here, Bf is the minimum required helical track width. However, the width Bi of the helical trucks 11 and 12 which is not affected by editing is

[0028]

(Equation 6)

## EQU1 ## which includes a margin of .delta.S1 + .delta.Se.

[0030]

In the magnetic recording method and the head drum device, as shown in the conventional example, the track pitches are considered evenly in consideration of the track shaving and the remaining track at the edit point. In addition, for helical trucks that are not affected by editing,
Because it has the same helical track width as the edit point,
There is a problem that the helical track has a margin and the magnetic tape cannot be used effectively. To solve the problem, a magnetic recording pattern and a head drum device which further improve the recording density are required.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a magnetic recording method and a head drum device which do not deteriorate at an editing point even with a narrow track pitch.

[0032]

In order to solve this problem, a magnetic recording method and a head drum device according to the present invention comprise a plurality of adjacent helical tracks in which two kinds of azimuth angles are alternately changed and at least not two. As a group, at least the helical tracks at both ends of the group of helical tracks are widened, and editing points of the helical tracks are arranged between the helical track groups.

As a result, a helical track that is affected by editing at the editing point can obtain a normal signal even if it is degraded by editing, and a helical track that is not affected by editing is a helical track that is affected by editing. A value smaller than the width can be set, and a magnetic recording pattern that can be recorded at a high density while guaranteeing the editing point can be obtained.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, at least two adjacent helical tracks in which two kinds of azimuth angle helical tracks are alternately recorded on a magnetic tape are grouped, The magnetic recording method, wherein the helical tracks at both ends of the group of helical tracks are wider than the inner helical track width, whereby the helical tracks eroded at the editing position are Erosion is reduced by widening or guarding, and helical tracks that do not face the editing position are narrower than the helical track width required at the editing point, so the average helical track width is small, that is, signals are recorded within a single area. More data can be recorded and editing can be performed reliably.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a schematic plan view of a magnetic recording pattern recorded by a magnetic recording method according to the present embodiment. In FIG. 1, 1 is a magnetic tape, 3 is a group of helical tracks consisting of four, 9 and 10 are helical tracks at both ends of the helical track group 3, and 5 and 6 are internal helical tracks in the helical track group 3. Truck, i is IT
I and a are audio, v is video, s is subcode, g
Is a gap between signals in the longitudinal direction of the helical track, which is common to each helical track.

The helical truck group 3 in this example is composed of four helical tracks 9, 5, 6, and 10, and each helical truck 9, 5, 6, 1 in the helical truck group 3.
0 ITI, Audio, Video, Subcode
Are side by side. The helical truck group 3 is further connected repeatedly. Helical truck 9,10
Are made wider than the helical tracks 5 and 6 by an error affected by editing. This value is roughly set to a value corresponding to δSe + δS1 shown in (Equation 1).

FIG. 2 is a plan view of the configuration of a magnetic head for recording by the magnetic recording method according to the present embodiment. In FIG. 2, reference numeral 24 denotes a rotary erase head, 25, 26, 27, and 28 denote recording heads, 33, 34, 35, and 36 denote reproduction heads,
Reference numeral 9 denotes a spare head. FIG. 3 shows the relationship between the helical track and the magnetic head. Recording heads 25, 26, 27, 2
Numeral 8 records helical tracks 9, 5, 6, and 10, and the rotary erasing head 24 is located at a position where the helical track group 3 is erased at a time.

When such a magnetic recording method is employed, a helical track width of 4Bf + 4δS is conventionally required for each helical track group, but in the present invention, 2Bf + 2δS + 2Bi is obtained for the helical track group, and 2δSe + 2δSl.
Only the helical track can be recorded efficiently.

(Embodiment 2) FIG. 4 is a schematic plan view of a magnetic recording pattern recorded by a magnetic recording method according to a second embodiment of the present invention. In FIG. 4, reference numeral 2 denotes a group of helical trucks consisting of four tracks, reference numerals 4 and 7 denote helical tracks at both ends of the helical truck group 2, reference numerals 5 and 6 denote helical tracks inside the helical truck group 2, and reference numerals 8 and
Is a guard between the helical truck group 2.

The helical truck group 2 is composed of four helical trucks 4, 5, 6, 7 in the present embodiment, and within the helical truck group 2, the helical trucks 4, 5, 6, 7
ITI, Audio, Video, subcode
Are arranged side by side. The helical truck group 2 is further connected repeatedly with the guard 8 interposed therebetween. The width of the helical tracks 4 and 7 is wider than that of the helical tracks 5 and 6 by an error at the time of editing. This value is roughly set to a value corresponding to δ1 shown in (Equation 1). Further, the width of the guard 8 is set substantially in the vicinity of track scraping δSe generated by the rotary erasing head 19.

FIG. 5 is a plan view of the configuration of a magnetic head for recording by the magnetic recording method according to the present embodiment. In FIG. 5, 19 is a rotary erase head, 20, 21, 22, and 23 are recording heads, 33, 34, 35, and 36 are reproduction heads,
Reference numeral 9 denotes a spare head. FIG. 6 shows the relationship between the helical track and the magnetic head. Recording heads 20, 21, 22, 2
Numeral 3 records the helical tracks 4, 5, 6, and 7, and the rotary erasing head 19 is located at a position where the helical tracks 3 are collectively erased, and is arranged at the preceding position in this figure. Also,
The width of the rotating erasing head 19 is set so that the width of the guard 8 is substantially in the vicinity of track scraping δSe generated by the rotating erasing head 19.

When such a magnetic recording method is adopted, the conventional helical track group requires a helical track width of 4Bf + 4δS, but in the present invention, the helical track group 3 is used.
The width is Bf + δS + 3Bi + δSl, and the helical track group 3 can be recorded at a higher density by 3δSe + 2δSl compared to the conventional uniform helical track width method.

(Embodiment 3) As shown in the magnetic recording patterns of FIGS. 1 and 4, one channel of audio is constituted by a minimum of four independent helical tracks in helical track groups 2 and 3, respectively. The video and the subcode form one frame with a group of 5 helical tracks, that is, 20 helical tracks. Audio editing is done at a minimum with this helical truck group 3 units,
At the time of editing, there is always a seam of editing between helical groups 2 or 3. That is, the editing point is always between the wide helical tracks 10 and 9 or between the wide helical tracks 7 and 4 with the guard 8 interposed between them. Secure the width Bf.

Further, the recording surface of the magnetic tape is effectively used in order to make the wide helical track required at the time of editing widen only the helical track affected at the time of editing by matching the minimum unit.

(Embodiment 4) FIG. 7 shows a schematic magnetic recording pattern recorded by the magnetic recording method according to the present invention.
In FIG. 7, 53 is a still locus, and 54 and 49 are drums 1.
The tape running distance at the time of 80 ° rotation, 55 and 50 are the center lines of the trajectory of the helical truck. The trajectory of the helical track is determined by the drum diameter d (mm), the still angle θs (゜), the tape speed vt (mm / s), and the drum rotation speed n (Hz). The basic formula is

[0046]

(Equation 7)

[0047]

(Equation 8)

Is as follows. Here, T is helical track pitch / 180 °. If the drum diameter d, the number of revolutions n, and the still angle are fixed, θr changes when vt is arbitrarily selected, and T
Can also be arbitrarily selected. That is, the angle θr of the helical track becomes a variable of the tape speed when the condition of the drum is determined. Therefore, when the tape speed vt is arbitrarily changed, θr is determined individually.

Comparing FIG. 7 with (Equation 7) and (Equation 8), the tape running distances 54 and 49 are vt / (2n), the still angle θs is the angle between the lower end of the magnetic tape 1 and the still locus 53, θ
r is the angle between the lower end of the magnetic tape 1 and the center lines 55 and 50 of the track of the helical track.

At this time, if the width of the single helical track 11 is adjusted to the width of the wide helical track 9, it is possible to record and reproduce a helical track having the same helical track width by adding one magnetic head. The head arrangement at this time may be set at the position of the helical track 12 by setting the spare head 29 arranged in FIGS.

When the width of the recording head 26 is the same as the width of the helical track 12, the helical tracks 11 and 12 can be scanned without disposing the spare head 29.

FIG. 8 shows the relationship between the magnetic recording pattern 1 and the magnetic recording pattern 2. The helical tracks 11 and 12 of the magnetic recording pattern 1 have substantially the same width as the helical tracks 9, 5, 6 and 10 of the magnetic recording pattern 2. The magnetic recording heads 25, 26, 27, 28 are arranged in conformity with the helical tracks 9, 5, 6, 10. Paying attention to the magnetic recording heads 25 and 26, these magnetic recording heads 25 and 26
2 and at the same height, ensuring helical trucks 11 and 1
2 can be recorded.

In this embodiment, it is easy to easily draw the magnetic recording pattern 1 without having any special spare head 29. In the present embodiment, an example in which there is no guard between the helical track groups has been described.

(Embodiment 5) FIG.
It is a front development view showing arrangement of 26,27,28. About 1
80 ° opposing print heads 25 and 26 and print head 2
Groups 7 and 28 are arranged. h0 is the height from the lower end of the recording head 27 to the lower end of the recording head 25; h1 is the height from the lower end of the recording head 27 to the lower end of the recording head 28; h2 is the height from the lower end of the recording head 27 to the lower end of the recording head 26 Height x0, x1, x2 is the recording head 27
Is the horizontal distance from

The heights h0, h1, h1 are defined assuming that the width of the helical tracks 4, 7 is Tw and the width of the helical tracks 5, 6 is Tn.
h2

[0056]

(Equation 9)

[0057]

(Equation 10)

[0058]

[Equation 11]

Is expressed by the following equation. 2 or 5 where the recording head 27 and the recording head 25 are attached at 180 °, h0 = 0. Further, when x1 is close to 0 and x2 is almost equal to x0, h2 = Tw,
h1 = Ts.

With respect to the basic set values of the heights h0, h1, and h2, mounting tolerances are required for mounting the heads. If the mounting tolerance is δh, the recording heads 25, 26, and 28 perform recording. The height h0 with respect to the head 27,
It has a tolerance of ± δh with respect to the attachment of h1 and h2. The recording heads 25, 26,
Since the scans 27 and 28 are performed, the print head 27 becomes the third print head. In the method in which the four helical tracks are grouped, the lower end of the helical track 6 is determined by the overwriting lower end position of the recording head 28 since the lower end of the recording head 27 for recording is the reference. The width is ± δh. On the other hand, the helical track 5 is recorded by the recording head 26, and the upper end is determined by the lower end of the recording head 27. Since the recording head 27 is a reference head, the width of the helical track 5 has a tolerance of ± δh.

As described above, the recording heads 25, 26, 27,
When the mounting of the helical tracks 28 is performed with reference to the lower end of the recording head 27, the helical track width tolerance of the helical tracks 5 and 6 set narrow is ± δh, and the helical tracks 4 and 7 of the wide width are ± δh.
Although it is 2δh, the position of the helical track that is never eroded is ± δh, and the helical tracks at both ends are more resistant to erosion.

This is because the helical trucks 9, 5, 6, 1
The same effect is produced for the recording heads 20, 21, 22, and 23 for recording 0.

Here, in this embodiment, the recording head is at the 180 ° position, but it goes without saying that the recording head may be at any position.

Further, in the embodiment of the present invention, an example has been described in which the helical track group is composed of four.
Needless to say, four or more can be used.

Although the arrangement of the magnetic heads has been described on the basis of 180 ° opposition, it goes without saying that the magnetic heads may be installed at any position.

Furthermore, although the description has been made with the drum rotation being constant, it goes without saying that the rotation number of the drum may be changed.

[0067]

As described above, according to the present invention, a plurality of helical tracks are grouped together and the width of the helical tracks at both ends is widened so that recording can be reliably performed even in a magnetic recording format having a narrow average track pitch. A high-density magnetic recording method can be provided, and its practical effect is very large.

[Brief description of the drawings]

FIG. 1 is a diagram showing a magnetic recording pattern recorded by a magnetic recording method according to a first embodiment of the present invention.

FIG. 2 is a schematic layout diagram of the magnetic head.

FIG. 3 is a schematic diagram of the magnetic recording pattern and a relative position of a magnetic head.

FIG. 4 is a diagram showing a magnetic recording pattern recorded by a magnetic recording method according to a second embodiment of the present invention.

FIG. 5 is a schematic layout diagram of the magnetic head.

FIG. 6 is a schematic diagram of the magnetic recording pattern and a relative position of a magnetic head.

FIG. 7 is a front view of a recording head arrangement according to a third embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a relationship between a magnetic recording pattern recorded by a magnetic recording method according to a fourth embodiment of the present invention and specifications.

FIG. 9 is a diagram illustrating the relationship between the magnetic recording patterns.

FIG. 10 is a schematic magnetic recording pattern diagram in a first conventional example.

FIG. 11 is a schematic magnetic recording pattern diagram in a second conventional example.

FIG. 12 is a diagram showing an example of a magnetic head arrangement for recording and reproducing the magnetic recording pattern;

FIG. 13 is a schematic diagram of insert editing of a rotation erasure method of a magnetic recording pattern in the first conventional example.

FIG. 14 is a schematic diagram of an insert editing of an overwrite type of the magnetic recording pattern.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Magnetic tape 2,3 Helical track group 4,5,6,7,9,10 Helical track 8 Guard 19,24 Rotation erase head 20,21,22,23,25,26,27,28 Recording head 30 Rotation drum 33, 34, 35, 36 playback head

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takanori Tabuchi 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. A group consisting of a plurality of adjacent helical tracks other than at least two, in which two types of helical tracks having two azimuth angles are alternately recorded on a magnetic tape, wherein the helical tracks at both ends of the group of helical tracks are inside. A magnetic recording method characterized in that the width is wider than the helical track width. 2. A plurality of non-at least two adjacent helical tracks each having two types of helical tracks having an azimuth angle alternately recorded on a magnetic tape as a group, and the helical tracks at both ends of the group of helical tracks are placed inside. And a guard band between the helical track groups. 3. A plurality of non-at least two adjacent helical tracks each having two types of helical tracks having an azimuth angle alternately recorded on a magnetic tape as a group, and the helical tracks at both ends of the group of helical tracks are placed inside. A magnetic recording method which is wider than the helical track and the minimum unit of the signal is made coincident with a group of the helical tracks. 4. A magnetic recording pattern 1 for recording a predetermined signal amount per unit time at which recording or reproduction can be performed on a helical track having a uniform width by at least a predetermined head drum device.
And a magnetic recording pattern 2 having a group of four helical tracks having a wide helical track width on both sides for recording a larger amount of signal per unit time than the magnetic recording pattern 1. Wherein one of the helical tracks is equal to the helical track width of the magnetic recording pattern 1. 5. A helical track comprising four adjacent helical tracks each having two kinds of azimuth angle helical tracks alternately recorded on a magnetic tape, wherein the helical tracks at both ends of the group of helical tracks are widened. Are arranged so as to sequentially record from the upstream in the running direction of the magnetic tape, and of the magnetic recording heads, the other magnetic recording heads are based on the third magnetic recording head that starts recording. A rotary drum device characterized by disposing.