JPH04307413A - Rotating head drum - Google Patents

Abstract

PURPOSE:To enable high density recording with high accuracy by arranging first and second erasing heads corresponding to first and second recording heads so that they can precede in the rotating direction of a rotating drum by the amount of 180 deg. plus alpha deg.. CONSTITUTION:The head is arranged so that it can precede ERASE A, B, C and D corresponding to REC A, B, C and D by the amount of 205 deg. in the rotating direction (the direction of an arrow (a)) of a rotating drum 2, respectively. In this case, at the time of editing a magnetic tape 2, all the channels A, B, C and D are precedingly erased during a single rotation in the arrow (a) direction of the rotary drum 2, and recording tracks RA and RD of the channels A and B and recording tracks RC and RD of the channels C and D are consecutively recorded on the erased tracks EA, EB, EC and ED. Thus, such accident that a part of the recording track RB of the precedingly recorded channel B is erased with the ERASE C of the channel C can be prevented.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a rotary head drum suitable for application to a magnetic recording/reproducing device such as a digital video tape recorder, and in particular to recording video signals on a magnetic tape in a guard bandless manner. and/or a rotating head drum for regeneration.

0002

2. Description of the Related Art Conventionally, there is a rotary head drum shown in FIG. 4 that has been applied to digital video tape recorders and records and/or reproduces video signals on a magnetic tape in a guard bandless manner. In this system, a plurality of two rotating heads called paired heads for recording and/or reproducing video signals are arranged around the outer periphery of a rotating drum 2 on which a magnetic tape 1 is helically wound and run. ing. And these rotating heads are the first and second
A, B, C, D of REC which is the recording head of
and the second erase head ERASE A, B and C.
, D, and A and B of PB, which are the first and second playback heads.
, C, and D.

[0003] Then, REC's A, B, C, D, ERA
SE's A, B, C, and D, and PB's A, B, C, and D are arranged facing each other at 180° on the outer periphery of the rotating drum 2. And ERASE A, B, C, and D are RE
A, B, C, and D of PB are arranged at a position 25 degrees ahead of A, B, C, and D of REC in the rotational direction of the rotary drum 2 (direction of arrow a), and A, B, C, and D of PB are arranged 25 degrees ahead of A, B, C, and D of REC. and C, D
It is arranged at a position delayed by 90° in the direction opposite to the rotational direction of the rotary drum 2 (in the opposite direction of arrow a).

Video signals are recorded and/or recorded on the magnetic tape 1 in a guard bandless manner by a helical scan method in which the rotating drum 2 rotates at high speed in the direction of arrow a.
Or it can be played back.

At this time, FIG. 5 shows the recording pattern when editing the magnetic tape 1, and the arrow a on the rotating drum 2
During one rotation in the direction, erase by A and B of ERASE, R
Recording (writing) by A and B of EC, C of ERASE,
Erasing by D and recording (writing) by C and D of REC are performed in the order of erased track E of channels A and B.
Recording tracks RA and R of channels A and B on A and EB
After recording B in advance, recording tracks RC and RD of channels C and D are recorded on erased tracks EC and ED of channel CD. Note that TR in the figure is a recording track on which a draft is being written.

[0006]

[Problems to be Solved by the Invention] However, in the conventional rotary head drum, REC A and B are recorded in advance of ERASE C and D.
ERA of track width W2 larger than track width W1 of D
When SE A, B, C, and D are used, the recording track RB of channel B is C of ERASE of channel C and has a width W3.
There was a problem in that the image was partially erased along (W3=W2-W1×1/2).

[0007]Furthermore, the installation error of ERASE A, B, C, and D directly led to the above-mentioned negative effects such as over erasing and leaving unnecessary records.

Therefore, in the conventional rotary head drum, unless A, B, C, D of REC and A, B, C, D of ERASE are controlled independently at different timings within one revolution of the rotary drum 2, When editing magnetic tape 1, overwriting occurs at the in and out points,
There is a problem in that recording tracks are unnecessarily erased or unnecessarily left.

The present invention has been made to solve the above problem, and provides a rotating head drum that prevents the erasing head from erasing part of the recording track previously recorded by the recording head. The purpose is to

0010

[Means for Solving the Problems] A rotary head drum of the present invention for achieving the above object includes first and second recording heads disposed around the outer periphery of the rotary drum, and a first recording head corresponding to these recording heads. , a rotary head drum having a second erasing head and first and second reproducing heads, and recording and/or reproducing video signals on a magnetic tape in a guard bandless manner using these heads, the first and second reproducing heads; The second recording head, the first and second erasing heads, and the first and second reproducing heads are each rotated at an angle of 180 degrees around the outer periphery of the rotating drum.
and the first and second erasing heads corresponding to the first and second recording heads are arranged in positions facing each other in the rotational direction of the rotary drum with respect to the first and second recording heads. They are arranged 180°+α° ahead of each other.

[0011]

[Operation] The rotary head drum of the present invention configured as described above has both the first and second erasing heads.
The recording head can be placed in advance of the other recording head.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a rotary head drum of a digital video tape recorder will be described below with reference to FIGS. 1 to 3. Note that the same reference numerals are given to the same structural parts as in FIGS. 4 and 5, and redundant explanation will be omitted.

First, FIG. 1 shows the arrangement of the heads, with E corresponding to A, B, C, and D of REC, respectively.
RASE A, B, C, D, these REC A, B
, C and D, respectively, by 205° in advance in the rotational direction of the rotary drum 2 (direction of arrow a). That is, 205°=180°+α°, α°=25°.

Next, FIG. 3 shows a time chart of ERASE and REC control during editing of the magnetic tape 1. Based on the input of the in point P1 of the insert command signal S1, the erase command signal S2 is ERASE A, B, C, and D are operated by A, B, C, and D. Then, by A and B of the recording command signal S3, the RE
A and B of C are 205 in Figure 1 for A and B of ERASE
After ERASE A and B are operated by erase command signals A and B of the erase command signal S1, REC C and D are operated by recording command signal S3 C and D.
It is operated with the above-mentioned time difference t with respect to C and D of RASE. Then, the out point P2 of the insert command signal S1
Until then, the relationship between ERASE and REC is completely maintained.

Therefore, according to this rotating head drum,
When editing the magnetic tape 1, as shown in FIG.
erase by ERASE, erase by C and D of ERASE, record (write) by A and B of REC, erase by A and B of ERASE, record (write) by C and D of REC. , C, and D in advance, and erase those erased tracks EA, EB, EC, and E.
Recording tracks RA and RD of channels A and B and recording tracks RC and RD of channels C and D are sequentially recorded on D.

Therefore, the previously recorded channel B
A part of recording track RB is ERASE of channel C.
It is never erased by C.

Moreover, as shown in FIG.
A, B, C, D of ERASE within one revolution of REC
Control of the timing of A, B, C, and D is very simple, as only one system is required.

Furthermore, as shown in FIG. 3, when editing the magnetic tape 1, the relationship between ERASE and REC is perfectly maintained from the IN point P1 to the OUT point P2 of the insert command signal S1. High-precision editing can be performed without overwriting at the out point P2, without unnecessary erasure of recorded tracks, or without unnecessary recording tracks.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various effective modifications can be made based on the technical idea of the present invention.

[0020]

[Effects of the Invention] Since the rotary head drum of the present invention is constructed as described above, it has the following effects.

[0021] Since both the first and second erasing heads can be moved in advance of the first and second recording heads, it is possible to erase part of the recording track that was recorded in advance. It is possible to prevent this from happening, and it is possible to perform high-precision, high-density recording.

[0022] Only one system is required to control the timing of the erasing head and recording head within one revolution of the rotating drum.
Its control is very easy.

[0023] The relationship between the erasing head and the recording head is completely maintained from the in point to the out point when editing a magnetic tape, and overwriting can be performed at the in point or out point.
Highly accurate editing can be performed without unnecessary erasure of recording tracks or unnecessary recording tracks.

[0024] In addition to being less susceptible to mounting errors of the erasing head, the track width of the erasing head can have a margin, so manufacturing is very easy.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view showing the arrangement of heads of a rotary head drum according to an embodiment of the present invention.

FIG. 2 is a drawing showing a recording pattern when editing the same magnetic tape as above.

FIG. 3 is a waveform diagram showing a time chart for controlling the erasing head and recording head same as above.

FIG. 4 is a schematic plan view showing the arrangement of heads of a conventional rotary head drum.

FIG. 5 is a drawing showing a recording pattern when editing a conventional magnetic tape.

[Explanation of symbols]

1 Magnetic tape 2 Rotating drum

Claims (1)

[Claims] [Claim 1] First and second parts arranged on the outer periphery of a rotating drum.
It has a recording head, first and second erasing heads, and first and second reproducing heads corresponding to these heads, and these heads record and/or record video signals on a magnetic tape in a guard bandless manner. Alternatively, in a rotary head drum for reproduction, the first and second recording heads, the first and second erasing heads, and the first and second reproducing heads are each opposed to each other at 180° on the outer periphery of the rotary drum. the first recording head corresponding to the first and second recording heads;
and a second erasing head, respectively, by 180 degrees in the rotational direction of the rotary drum with respect to the first and second recording heads.
A rotary head drum characterized by being arranged in advance by °+α°.