JPS6363992B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a helical scanning video tape recorder, and more particularly to a playback monitoring device in a video tape recorder that allows monitoring during recording.

One of the methods of recording television video signals on magnetic tape is to wrap the magnetic tape around a cylinder (drum) containing a rotating head and run it, creating a diagonal record of the video signal on the tape (video track).
There is a helical scanning video tape recorder device that forms a
It is widely used as professional equipment for broadcasting and other purposes.

In such professional helical-scan video tape recorder equipment, recording is performed on a rotating head assembly in order to erase the television signal on the formed video track and to monitor the television signal being recorded. In addition to the head, an erase head and a playback monitor head are provided.

These three heads are arranged on a rotating head assembly at 120° intervals in the rotational direction of the erase head → recording head → playback monitor head, and the erase head is positioned 1/3 of the video track pitch below the recording head. In addition, a reproduction monitor head is provided at an upper position. This allows the playback monitor head to monitor the video track formed by the recording head.

For example, in the case of insert editing, it is very convenient to be able to confirm whether a new program is correctly recorded in an unnecessary program portion. That is, it would be convenient to be able to monitor the television signal on the video track that is being erased by the erase head. However, since the playback monitor head only scans the video track formed by the recording head, it cannot scan the video track before it is erased by the erase head.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to use a video playback monitor head capable of monitoring a recorded television signal by scanning a video track immediately after it has been formed by a recording head. An object of the present invention is to provide a playback monitor device in a video tape recorder device which is capable of scanning a video track.

In the playback monitor device according to the present invention, the video playback monitor head is configured to be able to be displaced in a direction perpendicular to the rotational direction of the rotary head assembly (to the scanning plane), and the video track immediately after recording by the recording head and the video track by the erasing head are recorded. The video track immediately before erasing is switched and scanned.

Next, the present invention will be explained in detail with reference to the drawings.

Referring to the figure, tape 11 is deflected by guide pin 12 on the inlet side, contacts the periphery of rotary head assembly 13, and is further deflected by guide pin 14 on the outlet side to normally Proceed in the direction of the arrow. An erasing head 15, a recording head 16, and a reproduction monitor head 17 are mounted on the rotary head assembly 13. The rotary head assembly 13 rotates in the direction of the arrow, and the erasing head 15, the recording head 16, and the reproduction monitor head 17 are rotated in this order. Scan the tape 11.

After erasing head 15 erases previously recorded unnecessary signals, recording head 16 records the video signal. The playback monitor head 17 is a video playback monitor head that monitors the playback of the video signal.
The head is adapted to be displaceable in a direction perpendicular to the plane of rotation of the rotating head assembly 13, ie, to the recording track. As this displacement means, for example, the head displacement means disclosed in Japanese Unexamined Patent Publication No. 55-63187 can be used. It can also be done by other known means.

Typically, an erase head 15, a record head 16, and a playback monitor head 17 are mounted on the rotating head assembly 13 at 120 degree intervals. Considering the current signal recording state, the erasing head 15 is mounted below the recording head 16 by 1/3 of the track pitch. This is because the position of the recording head on the tape is one track is drawn by one revolution of the rotary monitor head, so the position of the erasing head, which is mounted 1/3 of a turn away, is only 1/3 of the track pitch. This is because it will shift.

Similarly, if the reproduction monitor head 17 is positioned 1/3 above the track pitch, the signal just recorded by the recording head 16 can be correctly reproduced, and it can be used as a monitor head for the recording state. I can do it. At this time, the playback monitor head 17 is moved and the recording head 16 is moved.
If the signal is located two-thirds of the track pitch lower than the original signal, the signal just before being erased by the erasing head 15 can be reproduced.

In the recording state, the tape is always being fed at a steady running speed, so the reproducing head 17 does not need to be dynamically moved and can be placed on the track simply by statically displacing it.

Therefore, the currently recorded signal or the previously recorded signal immediately before erasing can be switched and monitored by displacing the head, if necessary. Particularly in the case of insert editing, it is useful to be able to confirm that a new program is correctly recorded in an unnecessary program portion.

[Brief explanation of drawings]

The figure is a diagram showing the positional relationship between a tape, a rotary head assembly, an erasing head, a recording head, and a reproducing head in one embodiment of the present invention.

Claims (1)

[Claims] 1. In a video tape recorder device that uses a rotating head assembly to record and play back television video signals by scanning the tape diagonally, a video playback monitor head is provided in the rotary head assembly, and the video playback monitor head is used to scan the tape. A playback monitor device for a video tape recorder device, comprising means for displacing in a direction perpendicular to the surface, and capable of selectively playing back a video signal recorded immediately before and a video signal recorded previously. .