JP2915715B2 - Rotating drum - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating drum and a method for recording a video signal, and more particularly to a rotating drum and a video signal recording method suitable for an apparatus for magnetically recording a signal on a magnetic tape using a magnetic head provided on the rotating drum. Regarding the recording method.

[0002]

2. Description of the Related Art Magnetic recording devices such as DAT and VTR
And the like, a rotary drum provided with a magnetic head is provided. FIGS. 5 to 8 show the state of the arrangement of the magnetic heads in a rotary drum of a VTR as an example.

In FIG. 5, a rotary drum 31 is provided with a magnetic head HL for an L channel and a magnetic head HR for an R channel.
It is provided at an angular interval of 180 degrees. As shown in FIG. 6, the magnetic heads HL and HR are provided at the same position in the height direction of the rotary drum 31, so that there is no step between the magnetic heads HL and HR. . Note that, in FIG. 5, an arrow RV indicates the rotation direction of the rotating drum 31.

Tracks are formed on the magnetic tape T by the rotating drum 31 provided with the above-described magnetic heads HL and HR. FIG. 7 shows tracks TR1, TR2, TR3,.
.. Are shown in FIG.
/ 2) Tracks TR1, TR2, T formed at double speed
R3,... Are shown. For example, a video signal of the first field, that is, a video signal of horizontal scanning lines (hereinafter, referred to as H in this specification) 1 to 263 is recorded on the track TR1 shown in FIGS. In addition, 1H
262H are video signals for one horizontal scanning period, and 263H
H is a video signal in a (1/2) horizontal scanning period. Also,
In this specification, using the above-described magnetic heads HL and HR,
Tracks TR1, TR2,... Formed at 1 × speed
The track width of C is C as shown in FIG.

On the track TR2, a video signal of the second field, that is, a video signal of 263 to 525H is recorded. 264H to 525H are video signals in one horizontal scanning period, and 263H is a video signal in (1/2) horizontal scanning period. In FIGS. 7 and 8, DRT indicates the tape running direction.

[0006]

As described above, when the magnetic heads HL and HR are provided so that there is no step, at 1 × speed, the adjacent tracks TR1, TR2, and TR2, as shown in FIG. The video signal is recorded in a state in which the positions of the horizontal synchronizing signals HSY match between TR3,...

However, at (1/2) double speed, H between adjacent tracks TR1, TR2, TR3,...
It is not possible to realize the arrangement, and as shown in FIG. 8, there is a problem that a deviation of 0.25H or 0.75H occurs between the horizontal synchronization signals HSY of the adjacent tracks TR1, TR2, TR3,. Was.

If a video signal is recorded in a state where H arrangement is not performed, a crosstalk from the horizontal synchronizing signal HSY of an adjacent track occurs at the time of reproduction, and this crosstalk causes a beat disturbance on a screen. There was a problem.

[0009] The recording of the video signal in a state where the above-mentioned H arrangement is not performed, and the horizontal synchronizing signal H at the time of reproduction.
The occurrence of crosstalk from the SY to the video signal and the occurrence of beat disturbance occur at the (1/6) double speed in the same manner as at the (1/2) double speed, and improvement has been desired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to realize H arrangement at a specific double speed, crosstalk and beat in a state where H arrangement is not possible. An object of the present invention is to provide a rotating drum and a method of recording a video signal which can prevent occurrence of interference.

[0011]

Means for Solving the Problems] Such a rotary drum according to claim 1 invention is to solve the above problems, has at least a pair of magnetic heads for recording or reproducing a signal to the magnetic tape, the pair of magnetic The head is 0.25H (H
Is the correction required to record the video signal of one horizontal scanning line)
The angle is set at an angle interval of the value obtained by adding the angle to 180 degrees.
A predetermined step is set between the pair of recording magnetic heads , and the step is a, the head width of the reproducing magnetic head is d, and the track width of the magnetic tape at a predetermined speed is c. , D <a + c.

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[Operation] One magnetic head of the pair of magnetic heads is, for a predetermined period, for example, 0.25H (H
Are provided at an angular interval of a value obtained by adding a correction angle corresponding to one horizontal scanning line to 180 degrees. For this reason, after the first track is formed by the first magnetic head, the timing at which the formation of the second track is started by the second magnetic head is one pair of magnetic heads.
It changes by 0.25H as compared with the case where it is provided at an angular interval of 80 degrees. As a result, the deviation of 0.25H or 0.75H that occurs between the horizontal synchronization signals of the adjacent tracks at (1/2) speed or (1/6) speed is eliminated, and H arrangement can be realized.

The pair of magnetic heads are provided in a state having a step set in the range of (bc <a). In the above formula, a is a step, b is the head width of the magnetic head, and c is a guard bandless full track width formed by a magnetic head configured to have no step at a predetermined speed, for example, 1 × speed. . As a result, the position where the second track is formed is formed at a position offset from the position where the first track is formed by a step difference in the direction opposite to the running of the magnetic tape. Therefore, a guard band having the above-mentioned step difference is provided between the first track and the second track.

As described above, since there is a step between the pair of magnetic heads, the track of the second field of the above-mentioned first frame is formed at a position shifted from the original position by a step difference, and thereafter, is formed. The first track of the second frame is formed at the original position. During this time, the magnetic tape is caused to run at a predetermined speed regardless of the presence of the step. Accordingly, the first track of the second frame is formed over a part of the second track of the first frame.
For this reason, the second track of the first frame is a narrow track.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In this embodiment, a method of recording a video signal in a rotating drum of a VTR and a VTR is described as an example. 1 and 2, the rotating drum 1 is provided with a pair of L-channel magnetic heads HL and R-channel magnetic heads HR. The pair of magnetic heads HL and HR are used for recording and reproduction. FIG. 1 is a schematic view of the rotary drum 1 provided with the magnetic heads HL and HR as viewed from above.

The magnetic head HR is provided at an angular interval of (180 + θ) degrees clockwise with respect to the magnetic head HL. Represents a correction angle, and the correction angle θ is a radial line X passing through the center of the rotating drum 1.
In FIG. 1 showing a state in which the magnetic head HL is located on the line XA assuming A, in the clockwise direction from the line XA, the magnetic head HR outputs a video signal of 0.25H by the magnetic head HL. This is set as the rotation angle required for recording.

As shown in FIG. 2, the magnetic heads HL and HR are provided with a step a in the height direction of the rotary drum 1. In FIG. 2, the head width b of the magnetic heads HL and HR is (b <a + c).
In this formula, c is a state where there is no step at a predetermined double speed, for example, 1 × speed, that is, magnetic heads HL and H arranged at a = 0.
R is a guard bandless full track width formed by R. Note that, in FIG. 1, an arrow RV indicates the rotation direction of the rotating drum 1.

Tracks are formed on the magnetic tape T by the rotary drum 1 provided with the above-mentioned magnetic heads HL and HR. In FIG. 3, (1/1 /
2) Tracks TR1, TR2, TR3,... Formed at double speed or (1/6) double speed are shown. On the track TR1 shown in FIG. 3, for example, a first field, that is, a video signal of 1 to 263H is recorded.
1H to 262H are video signals in one horizontal scanning period, and 263H is a video signal in (1/2) horizontal scanning period.

On the track TR2, a video signal of the second field, that is, a video signal of 263 to 525H is recorded. 264H to 525H are video signals in one horizontal scanning period, and 263H is a video signal in (1/2) horizontal scanning period. In FIG. 3, DRT indicates the tape running direction.

The operation will be described below with reference to FIGS. The rotating drum 1 rotates, and on the magnetic tape T,
The tracks TR1, TR2,
.. Are formed. For example, the magnetic head H
L forms a track TR1, and the magnetic head HR
Thus, a track TR2 is formed. Hereinafter, similarly,
The odd-numbered tracks TR are formed by the magnetic head HL, and the even-numbered tracks TR are formed by the magnetic head HR.
Is formed.

The track TR1 is first formed with a track width c by a magnetic head HL having a head width b.
Next, the video signal of the second field is recorded on the track TR2 by the magnetic head HR.
Are provided so as to be deviated by a step a in the height direction of the rotary drum 1 with respect to the magnetic head HL. That is, since the track T is deviated by the step a, the track T
The position where R2 is formed is in a state of being shifted by the step a in the DRT reverse direction corresponding to the step a.

The track TR2 is a track T by a step a.
Since the recording is performed in a state deviated from R1, a guard band GB having a step a is formed between the tracks TR1 and TR2.

Next, a track TR3 is formed. As described above, since the track TR2 is formed so as to be deviated from the track TR1 by the step a, a part of the track TR2 is recorded so as to be deviated to a position where the track TR3 is to be formed. Therefore, the track TR3 is
The track TR2 is formed so as to overwrite the track TR2 by the step a. As a result, the track TR2 becomes the track TR
1, the track is narrower than TR3.

The magnetic head HR is a magnetic head H
L is provided at an angular interval of (180 + θ) degrees clockwise with respect to L, in other words, the magnetic head HR
Is delayed by 0.25H as compared with the state where the correction angle θ is not deviated.

Therefore, at the time of (1/2) or (1/6) double speed, the horizontal synchronizing signals HSY between the adjacent tracks TR2 and TR3 match, and H arrangement can be realized. For example, in FIG. 3, the track TR1 is moved by the magnetic head HL.
0.25H after the recording of the 263H video signal
Is elapsed, recording of the video signal of 263H on the track TR2 is started by the magnetic head HR.

When the reproduction is performed by the magnetic heads HL and HR, the magnetic head HR tracing the track TR2 is applied to the track TR3.
Since the H arrangement is performed between the TRs 3, no crosstalk of the synchronization signal HSY with respect to the video signal occurs and no problem occurs. In addition, the magnetic head HL is connected to the tracks TR1, TR3
When tracing a full track, no problem occurs because the full track is traced. When the head width of the reproducing head is larger than that of the recording head, for example, the area A in FIG.
As shown in R1, the head width d (d> b and d <a
In the case where the track TR1 having the track width c is traced and reproduced by the magnetic head HL2 of (+ c), the magnetic head HL2 can be prevented from covering the track TR2 by the guard band GB between the tracks TR1 and TR2. , H are not arranged, the occurrence of crosstalk is prevented.

In this embodiment, the magnetic heads HR are provided at angular intervals of (180 + θ) degrees clockwise with respect to the magnetic head HL.
Are provided in the height direction of the rotary drum 1 so as to have a step a, and the head width b of the magnetic heads HL and HR is set to (b <a + c).

Therefore, (1/2) double speed or (1/2)
6) The deviation of the horizontal synchronizing signal HSY occurring at the time of double speed can be eliminated without depending on the processing of an electric circuit, and H arrangement can be realized. For this reason, it is possible to prevent crosstalk with respect to the video signal from the horizontal synchronization signal HSY of the adjacent track, and prevent occurrence of beat disturbance on the screen. Also, the tracks TR1, which are not arranged in H,
A guard band GB can be formed between TR2, and even if the magnetic head HL2 used for reproduction is wider than the magnetic heads HR and HL used for recording, the deviation of the horizontal synchronization signal HSY between the adjacent tracks TR1 and TR2. Can be prevented, and beat interference on the screen can be prevented.

In this embodiment, a VTR is described as an example, but the present invention is not limited to this. For example, as a matter of course, the present invention can be applied to a device such as a DAT using a rotating drum having a pair of magnetic heads HL and HR.

[0036]

According to the present invention, a recording magnetic head can be used.
Steps a provided to form guard bands between tracks
it can. In addition, tracks without H arrangement are formed.
However, the head width d of the magnetic head used during reproduction is
Wider than recording magnetic head and wider than track width c
However, the guard magnetic band triggers the reproducing magnetic head.
Horizontal sync signal between adjacent tracks, regardless of rack
Crosstalk caused by misalignment can be prevented.
Can prevent the occurrence of
There is fruit.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of an arrangement state of a magnetic head provided on a rotating drum according to the present invention.

FIG. 2 is an explanatory diagram showing a positional relationship of a magnetic head in a height direction.

FIG. 3 is an explanatory diagram showing a track pattern formed by a magnetic head.

FIG. 4 is a diagram showing a trace of a track during reproduction.

FIG. 5 is an explanatory diagram showing an example of an arrangement state of a magnetic head provided on a conventional rotary drum.

FIG. 6 is an explanatory diagram showing a positional relationship of a conventional magnetic head in a height direction.

FIG. 7 is an explanatory diagram showing a tape pattern at 1 × speed.

FIG. 8 is an explanatory diagram showing a tape pattern at (1/2) speed.

[Explanation of symbols]

 HL, HR Magnetic head T Magnetic tape TR1, TR2, TR3 Track GB Guard band θ Correction angle a Step b Head width

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-46404 (JP, A) JP-A-62-49794 (JP, A) JP-A-49-43517 (JP, A) 109033 (JP, A) JP-A-6-60302 (JP, A) JP-A-61-290403 (JP, A) JP-A-59-189721 (JP, U) JP-A-2-12712 (JP, U) (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 5/53 G11B 5/02

Claims (1)

(57) [Claims] A pair of magnetic heads for recording or reproducing a signal on or from a magnetic tape ;
The magnetic head has a video signal of 0.25H (H is one horizontal scanning line).
The correction angle required to record the signal was added to 180 degrees
A predetermined step is set between the pair of recording magnetic heads , and the step is a, the head width of the reproducing magnetic head is d, and the predetermined Assuming that the track width at the double speed is c, d <a
A rotating drum characterized by having a relationship of + c.