JP3227740B2 - Rotary head device and rotary transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head device and a rotary transformer used in a video signal recording / reproducing apparatus having two modes having different tape speeds.

[0002]

2. Description of the Related Art As a conventional rotary head type VTR,
Mode (SP mode) and the second mode (LP mode)
) Are known. The tape speed in SP mode is twice that of LP mode. These two modes are selected in consideration of the length of video information to be recorded, the recordable time of a cassette tape to be used, the quality of image quality, and the like.

As shown in FIG. 8A, one conventional rotary head device has two heads H1 and H2 having different gap extending directions (referred to as azimuth angles) on a rotary drum 1 very close to each other. Some are provided. The two heads are integrally configured to share a component,
Also called double azimuth head, VX head and the like. As shown in FIG. 8B, these heads H1 and H2
They are mounted on the rotating drum 1 so as to have a step Ds equal to the track pitch in the SP mode. Therefore, the rotary head device of FIG. 8 is dedicated to the SP mode. As in FIG. 8, as shown in FIG.
2 is mounted in close proximity, and the rotary head device whose step Dp is equal to the track pitch of the LP mode is dedicated to the LP mode.

[0004] As shown in FIG. 10A, there is also known a configuration in which two heads H1 and H3 are mounted on the rotating drum 1 so as to face each other by 180 °. These rotary heads H1, H3
Have different azimuth angles, as shown in FIG. 10B. The rotary head device shown in FIG. 10 can be used not only for SP or LP but also for both modes. For this sharing, the LP mode has priority over the SP mode. That is, the track width of the heads H1 and H3 is set to be equal to or larger than the track pitch in the LP mode and equal to or smaller than the track pitch in the SP mode.

[0005]

As described above, FIG.
As a result of selecting the track width of the medium heads H1 and H3, SP
Since a guard band is generated in the mode, erasure is required.
If the SP mode is prioritized over the LP mode, that is, if the track width of the heads H1 and H3 is set to a track width equal to or larger than the track pitch of the SP mode, crosstalk from an adjacent track increases during reproduction in the LP mode.
Error rate increases.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rotary head device that can be used in both the SP mode and the LP mode, does not generate gad bands in the SP mode, and has little crosstalk from adjacent tracks even in the LP mode. .

Another object of the present invention is to provide a rotary transformer capable of improving a coupling coefficient and improving transmission efficiency as a rotary transformer for transmitting and receiving signals to and from a rotary head device commonly used in SP and LP modes. is there.

[0008]

According to the first aspect of the present invention, there is provided the following:
Mode (SP) and the second mode (LP).
In the track pitch mode (SP) (TP) is rotating head device for results in a doubling of video signal recording and reproducing apparatus of the second mode of the track pitch (tp '), to each other
With the opposite azimuth, and on the rotating drum (1),
First and second recording replays mounted close to each other
Raw head (H1, H2), one of the recording and reproducing head of the first and second recording <br/> heads (H1, H2) and 180
° Attach to opposite position , one recording and playback head
And a third recording / reproducing head (H3) having an azimuth opposite to that of the first and second recording / reproducing heads (H1, H2).
2) is that the track pitch of the first mode (SP) is (T
P) have the same step (Ds), and their track width is equal to or greater than the track pitch of the first mode (SP), and
Mode of the track pitch is set to a value of 3 times smaller range <br/> the circumference of (tp '), a third recording and reproducing head (H3)
Is that the track width of the first mode (SP) is equal to the track pitch (TP) of the second mode (LP).
Is set to a value between '), in a first mode (SP)
Corresponds to the first and second recording / reproducing heads (H1, H2).
Therefore, adjacent tracks are simultaneously formed, and the second mode
(LP), one recording / reproducing head and the third recording / reproducing
Adjacent tracks are alternately formed by head (H3)
A rotary head device characterized in that:

A rotary transformer according to a second aspect has a first mode (SP) and a second mode, and the first mode (S)
The rotary transformer track pitch P) (TP) is connected to the rotating head device for results in a doubling of video signal recording and reproducing apparatus of the second mode of the track pitch (tp '), the rotary head apparatus, to each other Have the opposite azimuth
Together with each other on the rotating drum (1)
The first and second read / write heads (H1, H
2) and first and second recording / reproducing heads (H1, H
2) at a position 180 ° facing one of the recording / reproducing heads
Attached, the azimuth opposite to one recording and playback head
Third recording and a reproducing head (H3) of having, first Oyo
And the second recording / reproducing head (H1, H2)
Step (D) equal to the track pitch of the track (SP) (D).
s) and their track widths are in the first mode (S
A track in the second mode which is equal to or more than the track pitch of P)
Set to a value within the range of less than three times the pitch (TP ')
Is, third recording and reproducing head (H3), the track width
Are the track pitch (TP) of the first mode (SP) and the
Set to a value between that of mode 2 (LP) and that of mode (TP ')
The winding angle of the tape is set to 180 ° or less, and the first
In the mode (SP), the first and second recording / reproducing heads are used.
(H1, H2) simultaneously form adjacent tracks
In the second mode (LP), one recording / reproducing head
And the third recording / reproducing head (H3)
A channel corresponding to the first head (H1) and a second head (H2) configured to alternately form racks;
Short ring SL only between the channel corresponding to
Is a rotary transformer characterized by the following.

[0010]

[Function] In the SP mode, the heads H having opposite azimuths are used.
1. A video signal is recorded / reproduced by H2. The steps of the heads H1 and H2 are made equal to the track pitch TP in the SP mode, and two adjacent tracks are formed at the same time. Since the track width of the heads H1 and H2 is slightly larger than TP, no guard band is generated. Therefore, an erasing head can be dispensed with. On the other hand, in the LP mode, the head H1,
A video signal is recorded / reproduced by one of the heads H2 and a head H3 having an interval of 180 ° facing the head H2. The track width of the head H3 is the track pitch LP in the LP mode.
Since it is about 1.5 times that of ', the adjacent track having the same azimuth during reproduction is not reproduced, and crosstalk can be reduced.

The head H1 or H2 and the head H3 do not scan the magnetic tape at the same time. Therefore, the short ring for isolation between the channels is formed by the head H
What is necessary is just to provide between the 1st channel and the channel of the head H2. Therefore, short rings can be united,
A decrease in the area of the rotor and the stator facing each channel can be prevented, and the coupling coefficient does not decrease.

[0012]

An embodiment of the present invention will be described below. In FIG. 1A, H1, H2, and H3 correspond to the rotating drum 1.
The head is attached to. Although not shown, the magnetic tape is wound around the peripheral surface of the rotating drum 1 at a winding angle smaller than about 180 °. On a magnetic tape running at a constant speed, a digital video signal or an analog video signal has two heads (that is, heads H1 and H2 in the SP mode) as oblique tracks.
In the LP mode, recording is performed by one of the heads H1 and H2 and the head H3). Each head is also used for reproduction. The running speed of the magnetic tape in SP mode is
Double that of LP mode. Therefore, the relationship between the track pitch TP in the SP mode and the track pitch TP 'in the LP mode is TP = 2TP'.

The heads H1 and H2 have an integral structure and are provided at positions very close to each other. FIG. 1A
As shown in the figure, the head H3 is the head H1 or H
2, for example, at a position 180 ° opposite to H1.
As shown in FIG. 1B, the heads H1 and H2 have azimuth angles (± θ) opposite to each other, and their height difference Ds is made equal to the track pitch TP in the SP mode. The track width of the heads H1 and H2 is equal to the track pitch TP or larger than the track pitch TP 'in the LP mode. This is necessary in order to prevent a guard band where no signal is recorded from occurring in a recording pattern on the tape formed in the SP mode. However, if the track width is too wide, in LP mode,
Crosstalk from adjacent tracks (tracks recorded by the same head with the same azimuth angle) increases. Therefore,
The track width is smaller than three times the track pitch TP '. In this embodiment, as an example, the head H
1, the track width of H2 is about 1.1 times the track pitch TP.

The head H3 used in the LP mode has the same azimuth angle -θ as the head H2, as shown in FIG. 1C. If the head H2 is used together with the head H3 in the LP mode instead of the head H1, as shown in FIG. 1D, it is necessary to have the same azimuth angle + θ as the head H1. The track width of the head H3 is a value between the track pitches TP and TP ', for example, about 1.5 times the track pitch TP'.

An example of a specific numerical value is (TP = 10 μm)
m, TP ′ = 5 μm), the step between the heads H1 and H2 (Ds = 10 μm), the track width of the heads H1 and H2 is about 11 μm, and the track width of the head H3 is about 7 to 8 μm
It is. Further, of the heads H1 and H2, the preceding head is located below the following head, and the height of the head H3 is the same as that of the head H1 and H2, which is the reverse azimuth.

In the SP mode, recording and reproduction are performed by the heads H1 and H2 having a track width slightly larger than the track pitch TP, so that a recording pattern without a guard band is formed on the magnetic tape 2 as shown in FIG. 2A. In FIG. 2A, Ta indicates a track formed by the head H1, and Tb indicates a track formed by the head H2. Each track records a video signal of one field. In the SP mode, the video signal is delayed by the memory, and the video signals of two fields are simultaneously recorded as tracks Ta and Tb by the heads H1 and H2.

In the LP mode, the heads H1 and H3
Or the head H2 and the head H3 record a video signal, so that a recording pattern as shown in FIG. 2B is obtained. The LP mode recording pattern recorded in this way is reproduced by the same head as at the time of recording. In this case, as shown in FIG. 3, the tracking control is performed so that the center of the head H1 or H2 coincides with the center of the recording pattern. Since the track width of the head H1 or H2 is smaller than three times TP ', adjacent tracks are not reproduced. Further, since there is a loss due to a difference in azimuth angle, crosstalk from an adjacent track is small.

The rotary heads H1, H2, H3 of the embodiment of the present invention shown in FIG. 1 are supplied with a video signal from a recording circuit at the time of recording, and take out a reproduced signal to the reproducing circuit. Is used. As this rotary transformer, a type in which a rotor made of a disk-shaped magnetic material and a stator are opposed to each other is known. Conventionally, a short ring has been inserted between each winding groove in order to reduce crosstalk between channels of the rotary transformer. However, when the diameter of the rotating drum and the diameter of the rotating transformer are reduced with the improvement in recording density, the facing area between the rotor and the stator for each channel is reduced by inserting a short ring. As a result, the coupling coefficient of the rotary transformer becomes small, causing a problem that the transmission effect is deteriorated.

In the rotary head device shown in FIG.
In the P mode, the heads H1 and H2 simultaneously perform recording / reproduction, and in the LP mode, one of the heads H1 and H2 and the head H3 alternately scan the magnetic tape.
Perform recording / reproduction. Therefore, in the SP mode, crosstalk between the two heads and the channels of the rotary transformer corresponding thereto increases. On the other hand, since the tape is wound around the rotary drum at an angle of 180 ° or less, L
In the P mode, two heads do not perform recording / reproduction at the same time, and as a result, crosstalk is small.

This means that a short ring is required between the channel of the head H1 and the channel of the head H2, but the short ring between the channel of the head H1 or H2 and the channel of the head H3 can be removed. It means you can do it. Therefore, the arrangement of the winding groove and the short ring of the rotary transformer shown in FIGS. 4, 5, 6 and 7 is possible. These arrangements are the same for the rotor and the stator of the rotary transformer.

In FIG. 4, the coil L2 of the channel of the head H2, the short ring SL, and the like are arranged in the groove formed concentrically on the disk (rotor or stator) 3 of the rotary transformer in order from the center to the outside. Coil L1 of channel of head H1, Coil L of channel of head H3
3 are arranged.

In FIG. 5, the coil L2 of the channel of the head H2, the short ring SL, and the like are arranged in a groove formed concentrically on the disk (rotor or stator) 3 of the rotary transformer in order from the center side to the outside. Coil L3 of channel of head H3, Coil L of channel of head H1
1 is arranged.

In FIG. 6, the coil L2 of the channel of the head H2 and the channel of the head H3 are arranged in a groove formed concentrically on the disk (rotor or stator) 3 of the rotary transformer in order from the center side to the outside. Coil L3, short ring SL, coil L of channel of head H1
1 is arranged.

In FIG. 7, the coil L3 of the channel of the head H3 and the channel of the head H2 are arranged in a groove formed concentrically on the disk (rotor or stator) 3 of the rotary transformer in order from the center side to the outside. Coil L2, short ring SL, coil L of head H1 channel
1 is arranged. 5, 6, and 7, the coil L
1 and the coil L2 can be interchanged.

[0025]

According to the head structure of the present invention, no guard band is generated even in the SP mode recording, so that a special erasing head is unnecessary. On the other hand, even in the LP mode, reproduction with little adjacent crosstalk can be performed without adjacent crosstalk, and a good error rate can be maintained. ADVANTAGE OF THE INVENTION The rotary transformer of this invention can reduce a short ring without deteriorating the crosstalk between channels, can improve a coupling coefficient, and can improve transmission efficiency.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of an embodiment of the present invention and a diagram showing azimuth of a head.

FIG. 2 is a schematic diagram for explaining a recording operation in an SP mode and an LP mode according to an embodiment of the present invention.

FIG. 3 is a schematic diagram for explaining a reproduction operation in an LP mode according to one embodiment of the present invention;

FIG. 4 is a schematic diagram illustrating an example of a channel arrangement of a rotary transformer to which the present invention is applied.

FIG. 5 is a schematic diagram showing another example of the channel arrangement of the rotary transformer to which the present invention is applied.

FIG. 6 is a schematic diagram showing still another example of the channel arrangement of the rotary transformer to which the present invention is applied.

FIG. 7 is a schematic diagram showing still another example of the channel arrangement of the rotary transformer to which the present invention is applied.

FIG. 8 is a schematic diagram illustrating an example of a conventional rotary head device.

FIG. 9 is a schematic diagram illustrating another example of a conventional rotary head device.

FIG. 10 is a schematic diagram showing still another example of the conventional rotary head device.

[Explanation of symbols]

 H1, H2, H3 Magnetic head 1 Rotary drum 2 Magnetic tape 3 Rotary transformer disk

Claims (2)

(57) [Claims] 1. A rotary head for a video signal recording / reproducing apparatus having a first mode and a second mode, wherein a track pitch of the first mode is twice as large as a track pitch of the second mode. A first and second recording / reproducing head having opposite azimuths and mounted on a rotating drum in close proximity to each other; and one of the first and second recording / reproducing heads
A third recording / reproducing head attached to a position 180 ° opposite to the recording / reproducing head, and having a azimuth opposite to that of the one recording / reproducing head, wherein the first and second recording / reproducing heads are Steps having a step equal to the track pitch of the first mode, and their track width is equal to or greater than the track pitch of the first mode ,
It is set to a value of 3 times smaller range <br/> the circumference of the track pitch of the second mode, the third recording head, a track pitch and above the track width is the first mode first It is set to a value between that of the second mode, in the first mode, the first and second recording reproduction
Adjacent tracks are simultaneously formed by the head, and in the second mode, the one recording / reproducing head and the
The adjacent tracks are switched by the third recording / reproducing head.
A rotary head device characterized in that they are formed mutually . 2. A rotary head for a video signal recording / reproducing apparatus having a first mode and a second mode, wherein a track pitch of the first mode is twice as large as a track pitch of the second mode. In a rotary transformer connected to the device, the rotary head devices have azimuths opposite to each other and are mounted on a rotary drum.
First and second recording and reproduction mounted in close proximity to each other
A head and one of the first and second recording / reproducing heads
Attached at a position 180 ° opposite to the recording / reproduction head
And a second recording / reproducing head with an azimuth
3 recording / reproducing heads, wherein the first and second recording / reproducing heads include the first mode.
Steps equal to the track pitch of the
When the rack width is equal to or greater than the track pitch of the first mode ,
Range smaller than three times the track pitch of the second mode.
The third recording / reproducing head is set to a value within the box .
The track pitch of the first mode and that of the second mode
The winding angle of the tape is set to 180 ° or less, and in the first mode, the first and second recording / reproducing are performed.
Adjacent tracks are simultaneously formed by the head, and in the second mode, the one recording / reproducing head and the
The adjacent tracks are switched by the third recording / reproducing head.
And a channel corresponding to the first head and the second recording head.
A rotary transformer characterized in that a short ring is provided only between a channel corresponding to a recording and reproducing head.